Nuclear waste management of the Olkiluoto and Loviisa nuclear … · 2013-10-07 · tinued with SKB. The analyses related to the failure of several canisters and research into the

Nuclear waste management of the Olkiluoto and Loviisa

nuclear power plants

Summary of operations in 2012

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Abstract

This document is a summary of nuclear waste management activities during 2012 for the Olkiluoto and Loviisa pow-er plants. The summary includes a report of the status and actions of nuclear waste management by the power companies in 2012, as prescribed by the Nuclear Energy Act and Decree.

In 2000, the Government made a decision-in-principle regarding Posiva’s application for fi nal disposal of spent nuclear fuel in Olkiluoto, Eurajoki. In 2003, the Ministry of Trade and Industry decided that the construction licence for the encapsulation plant and the disposal facility must be applied for by the end of 2012. Posiva submitted its construc-tion licence application to the Ministry of Employment and the Economy at the end of 2012. The application consisted of documents prescribed in the Nuclear Energy Decree regarding, among other things, the company, the disposal site, the plant complex to be built, the plan-ning and safety principles and safety signifi cance. In addition, the documents required in earlier decisions-in-principle regarding transports, retrievability and environmental impacts were also at-tached to the application. In connection with submitting the application, the Radiation and Nuclear Safety Author-ity (STUK) was provided with the re-ports prescribed in the Nuclear Energy Decree, the Government decree and STUK’s YVL Guides.

In 2012, the preparations for fi nal disposal of spent nuclear fuel progressed in line with the TKS-2009 programme. The TKS-2009 programme contains a description of the planned actions and their preparations during 2010–2012. The YJH-2012 programme was sub-mitted to the ministry in September 2012. It describes the current status of research, development and planning work regarding the final disposal of spent nuclear fuel and more detailed plans for 2013–2015.

The excavation of facilities defi ned for the ONKALO volume was almost totally completed in 2012. The main drawings of ONKALO and the disposal facility were completed in December 2012 and attached to the construction licence application. During the year, the focus of ONKALO construction work was shifted from tunnel excavation to actual construction and automation in-stallations.

The investigation of the Olkiluoto area continued in 2012 and included collection of data from drillholes and investigation trenches. The investigation will provide information on the char-acteristics of the bedrock and ground-water in the area. As in previous years, the geological mapping of ONKALO progressed at the same pace as the ex-cavation work. During the year, various studies took place both in the investiga-tion niches and in the demonstration facilities and other areas of ONKALO.

Modelling of the Olkiluoto area is coordinated by the Olkiluoto Model-ling Task Force, whose work involves interpretation and modelling work of the different research disciplines (geology, geophysics, hydrogeology, hydrogeo-chemistry and rock mechanics), aimed at complementing the understanding of the site. A report integrating and com-piling the site description was published in late 2012.

The changes possibly caused by the construction of ONKALO have been monitored with a programme (OMO) established for the purpose. The scope of the programme includes rock-mechani-cal, hydrological and hydrogeochemical monitoring and monitoring of the sur-face environment and foreign materials. The results of monitoring studies are published separately for each discipline.

In 2012, the design work for the encapsulation plant and the disposal facility concentrated on producing the construction licence application docu-

ments. Plan updates of the different systems of both the encapsulation plant and the disposal facility were completed during the year. The development work for installation and transfer techniques involved commencement of the con-struction of prototypes for the canister transfer and installation and bentonite block transfer and installation vehicles.

Posiva has produced a safeguards control manual that describes the con-trol during the construction phase of ONKALO. In its current form, the manual covers the period during which the construction licence application for the encapsulation plant and the disposal facility is being processed.

The work included in the Under-ground Openings task complex in 2012 involved the implementation of demon-stration facilities together with boring of test deposition holes, grouting and reinforcement, as well as implementa-tion of excavation damage zone (EDZ) investigations.

The disposal canister design docu-mentation was updated during 2012 to correspond to the results of completed research and development work and to the requirements set for the background material of the construction licence ap-plication. The development work for both the canister manufacturing tech-nology and the canister weld inspection techniques continued during 2012 in cooperation with Svensk Kärnbränsle-hantering AB (SKB) of Sweden. De-velopment work on the canister sealing process using the electron beam welding (EBW) method has continued.

Bentonite buffer development work continued in 2012 in the form of vari-ous studies, tests and manufacturing tests. Following the buffer design work undertaken during the last few years, a buffer production line report was pub-lished at the end of 2012 as part of the construction licence application process.

In 2012, the development work for

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backfi ll techniques of deposition tunnels concentrated on updating the deposition tunnel backfi ll design, and the backfi ll production line report was completed. The end plug of the deposition tunnel is also included in the report.

In 2012, one of the key tasks re-lated to producing the safety case was the compilation of the Safety Case report portfolio that was attached to the construction licence application. In conjunction with the research on the performance of release barriers, Posiva cooperated as usual with Finnish and foreign companies during the year and participated in several international projects.

In parallel with the vertical disposal design now constituting Posiva’s refer-ence solution, the development work for the horizontal disposal design has con-tinued with SKB. The analyses related to the failure of several canisters and research into the long-term interaction of titanium were among the activities initiated in 2012. The production of two production line reports also began in 2012.

The well-established practical mea-sures regarding operating waste from Olkiluoto and Loviisa power plants were continued, as were the research projects on this subject. In-service monitoring of the VLJ repository in Olkiluoto contin-

ued in accordance with the VLJ reposi-tory bedrock research and monitoring programme. The in-service studies on the Loviisa operating waste repository also continued in 2012 in line with the monitoring programme.

The decommissioning plan of Olki-luoto NPP was last updated in 2008. The work for re-assessing the extent of dismantling and demolishing work involved in decommissioning the plants in operation and for the decommission-ing of the spent fuel storage were com-pleted in 2012. The work for updating the decommissioning plan of the Loviisa power plant was completed at the end of 2012.

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Table of contents

INTRODUCTION ............................................................................................................................................ 7 Responsibilities and obligations of nuclear waste management ................................................................. 7 Schedules for nuclear waste management ................................................................................................... 8 Present status of the storage of spent fuel ................................................................................................... 8 The YJH-2012 programme .......................................................................................................................... 9 European cooperation .................................................................................................................................. 9

ONKALO ........................................................................................................................................................ 10 Design work .............................................................................................................................................. 10 Construction .............................................................................................................................................. 11

CHARACTERISTICS AND SUITABILITY OF THE REPOSITORY SITE ................................................ 12 Description of the bedrock and surface environment in Olkiluoto ........................................................... 12 Field surveys ........................................................................................................................................ 12 Research conducted in ONKALO ....................................................................................................... 12 Modelling............................................................................................................................................. 15 Bedrock classifi cation .......................................................................................................................... 17 Monitoring programme ............................................................................................................................. 17 Rock mechanics ................................................................................................................................... 17 Hydrology ............................................................................................................................................ 18 Hydrogeochemistry ............................................................................................................................. 19 Surface environment ............................................................................................................................ 20 Foreign materials ................................................................................................................................. 20

PLANT DESIGN ............................................................................................................................................ 21 Encapsulation plant ................................................................................................................................... 21 Disposal facility ......................................................................................................................................... 22 Installation and transfer techniques ........................................................................................................... 22

CONTROL OF NUCLEAR MATERIALS AND NUCLEAR NON-PROLIFERATION (Safeguards) ........ 23

DISPOSAL SYSTEM ..................................................................................................................................... 24 Underground Openings ............................................................................................................................. 24 The canister ............................................................................................................................................... 25 Canister manufacture ........................................................................................................................... 26 Sealing the canister .............................................................................................................................. 26 Canister weld inspections .................................................................................................................... 26 The buffer .................................................................................................................................................. 27 Tunnel backfi lling ...................................................................................................................................... 27 Closure of the facilities ............................................................................................................................. 29

MAIN ITEMS OF THE SAFETY CASE AND THE PRODUCTION PROCESS ....................................... 30 Plan for the production of evidence in support of the Safety Case ........................................................... 30 Performance of release barriers ................................................................................................................. 30 External conditions .............................................................................................................................. 30 Fuel ...................................................................................................................................................... 31 The canister .......................................................................................................................................... 31 The buffer, backfi lling and closure of the repository ........................................................................... 32 Bedrock as a release barrier ................................................................................................................. 32 Biosphere ............................................................................................................................................. 33

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DEVELOPMENT OF THE HORIZONTAL DISPOSAL SOLUTION ......................................................... 34

LICENCING AND OTHER ACTIVITIES .................................................................................................... 36 Construction licence application ............................................................................................................... 36 Other licences, permits and decisions required ......................................................................................... 36 Quality and environment management ..................................................................................................... 37 Occupational safety ................................................................................................................................... 37 Information management .......................................................................................................................... 38

OPERATING WASTE MANAGEMENT ...................................................................................................... 39 The Olkiluoto power plant ........................................................................................................................ 39 Principle of operations ......................................................................................................................... 39 Current status of storage and disposal ................................................................................................. 40 In-service studies regarding the VLJ repository .................................................................................. 41 Research related to operating and decommissioning waste ................................................................ 43 The Loviisa power plant ............................................................................................................................ 46 Principle of operations ......................................................................................................................... 46 Repository ............................................................................................................................................ 47 Studies on solidifi cation methods ........................................................................................................ 47 In-service studies regarding the repository .......................................................................................... 47 Safety reports regarding the disposal of operating waste .................................................................... 48

DECOMMISSIONING PLANNING ............................................................................................................. 49 The Olkiluoto power plant ........................................................................................................................ 49 The Loviisa power plant ............................................................................................................................ 49

PROVISIONS FOR THE COST OF NUCLEAR WASTE MANAGEMENT .............................................. 51

LIST OF REPORTS ........................................................................................................................................ 52

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Introduction

Responsibilities and obli-gations of nuclear waste management

The companies using nuclear energy to generate electricity in Finland, Teollisu-uden Voima Oyj (hereinafter “TVO”) and Fortum Power and Heat Oy (here-inafter “Fortum”) must, pursuant to the Nuclear Energy Act, carry out the actions included in the management of nuclear waste produced by their Olkil-uoto and Loviisa nuclear power plants and bear their costs. According to the Nuclear Energy Act, the Ministry of Employment and the Economy (abbre-viated as TEM in Finnish) decides on the principles to be followed in nuclear

Teollisuuden Voima Oyj has two boiling water reactors in Olkiluoto, Eura-joki. Olkiluoto 1 (OL1) was fi rst connected to the national grid in September 1978, followed by Olkiluoto 2 (OL2) in February 1980. In 2012, the load factor of OL1 was 90.4% while that of OL2 was 96.9%. The operating licences for the OL1 and OL2 power plant units and the low-level waste (MAJ Storage), intermediate-level waste (KAJ Storage) and interim spent fuel storages (KPA Storage) are valid until the end of 2018. The operating licence for the Olkiluoto repository for operating waste (VLJ repository) is valid until the end of 2051. TVO’s third NPP unit, Olkiluoto 3 (OL3), is also under construction, and preparatory work for the next plant project, Olkiluoto 4 (OL4), is progressing in line with the decision-in-principle received in 2010.

In 2012, the most extensive modifi cation work in the history of OL1 was implemented, the most signifi cant part of this work being extensive mod-ernisation. At OL2, similar modifi cations were carried out in 2011, and in 2012, the plant unit was due for a short refuelling outage. The modernisa-tion work allowed increasing the rated output of both OL1 and OL2 from 860 MWe to 880 MWe.

The Loviisa power plant of Fortum Power and Heat Oy has two pressurized water reactors, both with a rated output of 496 MWe. The commercial opera-tion of Loviisa 1 (LO1) began in May 1977, and that of Loviisa 2 (LO2) in January 1981. In 2012, the load factor of LO1 was 83.8% while that of LO2 was 90.9%. In 2012, LO1 had an extensive annual maintenance outage that takes place every eight years. LO2 had a short annual maintenance outage.

The operating licences for the LO1 and LO2 plant units and for their nuclear fuel and nuclear waste management facilities are valid until the end of 2027 for LO1 and until the end of 2030 for LO2. The operating licence for the operating waste repository (VLJ repository) is valid until the end of 2055.

waste management. These principles were presented by the former Ministry of Trade and Industry (Abbreviated as KTM in Finnish; its responsibilities were taken over by TEM) in its decisions dated 19 March 1991, 26 September 1995, 23 October 2003 and most recent-ly in its decision regarding the nuclear waste management of Olkiluoto 3 on 9 December 2011. These decisions form the starting point for both the practical implementation of nuclear waste man-agement and the research and develop-ment work concerning future measures.

Posiva Oy (Posiva) is a company jointly owned by TVO and Fortum. It is in charge of R&D work regarding the fi nal disposal of spent nuclear fuel as

well as the construction and operation of the encapsulation plant and disposal facility. TVO and Fortum will separately take care of all operations related to the handling and fi nal disposal of low- and intermediate-level operating waste and the decommissioning of power plants and interim storages of spent nuclear fuel.

Posiva is responsible for produc-ing, on behalf of its owners, the annual report on nuclear waste management operations at the Olkiluoto and Loviisa nuclear power plants. This is the report on operations in 2012; it contains the report required by the Nuclear Energy Act and Decree on the status of nuclear waste management at the named power companies in 2012.

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Schedules for nuclear waste management

Posiva submitted the construction li-cence application for the encapsulation plant and disposal facility to the Govern-ment at the end of 2012. The goal is to start the fi nal disposal of spent fuel in the early 2020s. Before that, spent fuel will be temporarily stored at the power plant sites in water pools.

In compliance with the Nuclear En-ergy Act and decisions of the ministry, preparations are made for disposing of all spent fuel currently held at the Olkil-uoto and Loviisa plants inside the Finn-ish bedrock. In its decision of 23 Octo-ber 2003, the ministry set the schedule of preparations for the disposal of spent fuel so that the preliminary reports and plans required for the construction li-cence for the encapsulation plant and the disposal facility had to be submitted in 2009. The fi nal reports and plans had to be available by the end of 2012.

In December 2000, the Government made a decision-in-principle regarding Posiva’s application for fi nal disposal of spent fuel in Olkiluoto, Eurajoki. Parlia-ment ratifi ed the decision almost unani-mously in May 2001. The decision-in-

principle is valid until 17 May 2016.A decision-in-principle was made in

2002 regarding the fi fth NPP unit in Fin-land (OL3). At the same time, a further decision-in-principle was made regard-ing the construction of the repository in expanded form so that it would also ac-commodate the spent fuel from the OL3 plant unit currently under construction. The nuclear waste management obliga-tion of the OL3 plant unit only begins when the plant is operational. The same applies to the latest decision-in-principle made in 2010 regarding TVO’s plant unit OL4.

The preparations for fi nal disposal of spent nuclear fuel progressed in 2012 in line with the TKS-2009 programme published in September 2009. Figure 1 shows the overall time schedule for nuclear waste management.

Present status of the storage of spent fuel

The spent fuel from Olkiluoto NPP is temporarily stored in the power plant units and in the interim storage of spent fuel (KPA storage) at the power plant site. The KPA storage can currently ac-commodate the spent fuel of approxi-

mately 30 years’ worth of production at the OL1 and OL2 units.

The expansion project for the in-terim storage began in 2009. The site and construction work is scheduled for 2010–2013 so that the extension could be commissioned in early 2014. Three pools will be constructed in the expan-sion project. A new pool must be in operation for the OL1 and OL2 plant units in 2014, while the OL3 unit is ex-pected to need its fi rst pool in 2020. The expansion project is implemented as a structural alteration project of a nuclear facility. The operating licence of OL1 and OL2 units has ample capacity for storing the fuel from these units. The permission for expanding the capacity and for storing fuel to accommodate the needs of OL3 will be applied for in connection with the operating licence application for OL3.

During the reported year 2012, the 33rd refuelling operation took place at OL1 and the 31st at OL2. At the end of the year, the quantity of spent fuel in storage amounted to a total of 7,886 bundles containing an approximate to-tal of 1,327 tonnes of uranium. Of all the assemblies in storage, 6,556 were placed in the KPA storage, 670 in the

Figure 1. Overall time schedule for nuclear waste management in line with the YJH-2012 programme.

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water pools of OL1 and 660 at OL2. Additionally, 500 assemblies were in use in the OL1 reactor, with another 500 in use in the OL2 reactor. The fi gures are inclusive of fuel placed in fuel rod racks (one per plant) used for the storage of damaged fuel rods (a total of 38 rods at the end of 2012).

Spent nuclear fuel produced in Lo-viisa is also stored at the power plant and in the interim storages of spent fuel. New spent fuel storage pools were last constructed at the Loviisa site in 2000. A decision has been made to equip the cur-rent pools with high-density racks. This will provide additional capacity until the early 2020s when the transportation of spent fuel for disposal is expected to start. The plan is to purchase the next batch of high-density racks in 2013.

At the end of 2012, the quantity of spent fuel stored at the Loviisa power plant amounted to a total of 4,507 assemblies, corresponding to an ap-proximate quantity of 543 tonnes of fresh uranium. Of that number, 174 as-semblies were stored at LO1 and 347 at LO2. Spent fuel storages 1 and 2 held 480 and 3,506 assemblies, respectively. Additionally, 313 assemblies were in use in the LO1 reactor, with another 313 in use in the LO2 reactor.

The YJH-2012 programme

In addition to the annual report on op-erations, Posiva also produces an overall programme for nuclear waste manage-

ment every three years. The YJH-2012 programme prepared by Posiva, outlin-ing the research, development and plan-ning work related to spent nuclear fuel disposal, was submitted to the Ministry of Employment and the Economy at the end of September in keeping with the schedule. The three-year plan re-ferred to in section 74 of the Nuclear Energy Decree used to be entitled the TKS programme. As the focus of work aimed at fi nal disposal changes from R&D to implementation, it was deemed appropriate to change the name of the document into a nuclear waste manage-ment programme, and consequently, this document is entitled YJH-2012 programme.

The YJH-2012 programme describes the current status of fi nal disposal of spent fuel and the plans for 2013–2018. In addition, the report describes the cur-rent status and future plans regarding the storage of spent fuel, the process-ing of operating waste and decommis-sioning for which TVO and Fortum are responsible.

European cooperation

Posiva’s participation in the joint proj-ects studying the subsystems of the fi nal disposal system and the perfor-mance of release barriers under the 7th framework programme of Euratom is guided by the strategic research plan of the technology platform for imple-menting geological disposal (IGD-TP).

The latest programme was produced in 2011, and its implementation plan was published in 2012. The joint projects of the 7th framework programme entitled LUCOEX, FIRST Nuclides, DOPAS and BELBaR were also part of the pan-European implementation of the stra-tegic research programme of IGD-TP, established in 2009. Posiva is a founding member of the technology platform. The implementation of individual projects in 2012 is presented in greater detail in Chapters 6 and 7.

Posiva investigates and develops the fi nal disposal concept in coopera-tion with its Swedish counterpart SKB (Svensk Kärnbränslehantering AB). Posiva and SKB have agreed on co-operation for the purpose of avoiding the duplication of efforts, enhancing the use of resources and promoting the social acceptance of fi nal disposal. The cooperation agreement facilitates implementing joint projects and sharing their costs. The fi rst cooperation agree-ment was signed in 2001, and the term of the agreement was last extended in 2011 by three years, i.e., until the end of 2014. Since 2001, about 160 joint projects have been implemented under the agreement.

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ONKALO

Design work

The main drawings of ONKALO and the disposal facility (Figure 2) appended to the construction licence application were completed in December 2012. At the same time, the fi re plan for ONKA-LO was updated, and the part regarding the preparatory phase of the disposal facility was added to the plan. In paral-lel with the main drawings, a 3D space model of ONKALO and the disposal facility was also produced.

The planning produced updates for the construction, structural, electricity and HPAC work plans for the technical-level construction phase. During 2012, excavation planning produced the more detailed excavation and grouting plans of level -455 m for the inlet air shaft and the personnel shaft from level -290 m to level -437 m. In connection with rock engineering design, plans were pro-duced for the excavation of demonstra-tion tunnels and for implementing test

ONKALO, the Underground Rock Characteriza-tion Facility, provides accurate information for the detailed planning of disposal facility and for assessing the safety and construction engineering solutions. ONKALO allows for the testing and demonstrations of disposal techniques in actual conditions. The construction licence application for ONKALO was submitted to the Municipality of Eurajoki in May 2003, and the construction work began in June 2004.

Two demonstration tunnels have been excavated at the disposal depth (-420 m); the latter of the two was completed in early 2012. The demonstra-tion tunnels are used for investigating and testing the actual disposal operation and its associated procedures. The technical rooms required for fi nal disposal operations will be at level -437 m, and the excavation of these facilities was com-pleted in 2012. Research has been conducted in ONKALO since the beginning of its construction.

deposition holes.As-built drawings were produced for

access tunnel sections TU1–TU4 during 2012. Computer images were produced during 2012 for ONKALO’s safeguards report. Review meetings for systems and plans were organized approximately twice every month.

The construction and excavation plans of the hoist building were com-pleted during 2012 for the purpose of in-viting contract tenders. The design work for the hoist building was implemented in all design disciplines (architectural, structural, electrical, HPAC and build-ing automation).

Figure 2. Main drawing areas for ONKALO (in red) and the prepara-tory phase of disposal facility (in blue).

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Area planning continued in 2012, and the matters specifi ed in greater de-tail included road arrangements in the ONKALO area and security arrange-ments for the area. Updates of area plans were produced for the years 2012, 2014, 2018 and 2020.

Construction

In 2012, the focus of ONKALO con-struction work was shifted from tunnel excavation to actual construction and building automation installations.

The excavation of facilities defi ned

for the ONKALO volume was almost totally completed in 2012. One of the latest excavated facilities was the pump-ing station loop to the lowest level of ONKALO at -455 m to chainage 4986 (= distance from the mouth of the tunnel in metres, the end point of ONKALO). In addition, the demonstration tunnels were completed for the needs of research and development work. The demonstration tunnels were 105 m (Tunnel 2) and 52 m (Tunnel 1) long.

When the excavation ended in the summer 2012, the construction work for the technical rooms began. It will include

the construction of concrete structures at the technical level -437 m and HPAC installations to the end section of the ac-cess tunnel for a stretch of about one and a half kilometres.

The excavation for the second phase of the hoist building began above ground in late 2012. The hoist building will be located next to the ventilation building completed in 2011.

The investment of resources in the occupational safety of construction work produced the desired result in 2012 when the accident frequency at the ONKALO

site was zero at the end of the year.

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Characteristics and suitability of the repository site

Description of the bed-rock and surface environ-ment in Olkiluoto

FIELD SURVEYSThe drilling investigations in the eastern part of the Olkiluoto survey area still continued in January 2012 with respect to the last few metres of drillhole OL-KR56 and washing of the hole. In addi-tion, hole OL-KR57B (45 m) covering the common tubed section of holes OL-KR56 and -57 was drilled. The purpose of drilling investigations is to supplement the coverage of site survey results also in the eastern area of the Olkiluoto island.

One new investigation trench, OL-TK19, was also excavated in the survey area, exposing and cleaning the bedrock surface in the trench. Geological map-ping was performed for the bedrock surface, and the continuity of the brittle zone modelled for the area was inves-tigated. Samples were also taken from different moraine layers in the trench for mineralogical analyses for the purpose of establishing the abundance of carbon-ates and sulphides in the Olkiluoto soil.

In addition to the investigations com-pliant with the monitoring programme (presented later in this document), the hydrogeological studies concentrated on measuring the fl ow characteristics in the bedrock of the eastern part of the survey area using both Posiva Flow Log (PFL DIFF) and Hydraulic Testing Unit (HTU) equipment. PFL DIFF equip-ment was used for measuring drillholes OL-KR56 and OL-KR57. HTU mea-surements were conducted in drillholes OL-KR54 and OL-KR55. Interference tests were also conducted in the east-ern area. The hydraulic connections between drillholes OL-KR49 and -50 were investigated by lowering the pres-sure level of groundwater in one hole and by measuring the other hole using PFL DIFF equipment. In addition, the

hydraulic connections were investigated by conducting PFL DIFF measurements in the drillholes of the eastern area while groundwater sampling was in progress in drillhole OL-KR56, causing a change in the groundwater level. Transverse fl ow measurements (PFL TRANS) were also carried out in drillholes OL-KR32, -40 and -42.

The results obtained from hydro-geological studies are used in hydro-geological modelling as background data for the hydrogeological structure model and fl ow models and for planning other studies, such as the water sampling programme.

Groundwater sampling was per-formed in line with the monitoring and characterisation programmes. The fo-cus was on the monitoring of potential salinity changes caused by ONKALO and also on the monitoring of sulphide observations made in connection with the characterisation activities. Samples were also taken from deep drillholes OL-KR55 and OL-KR56 which had not been previously characterised. In addition, the earlier sampling network in the northern part of the island was supplemented. In addition to ground-water chemistry samples, gas samples and microbial samples were also taken for analysis.

The three-year field test regard-ing infi ltration of surface water into groundwater (INEX) was completed in 2012. The purpose of the test was to investigate the buffering capacity of the bedrock against acidic and oxygen-containing sinking surface water. Infi l-tration was accelerated by pumping an isolated bedrock fracture belonging to the top section of zone HZ19 in hole OL-KR14 and by monitoring the hy-drology and groundwater composition in nearby shallow bedrock holes and groundwater tubes. The measurement results were assessed with the help of fl ow modelling of the surface hydrol-

ogy and hydrogeochemical reactive migration simulations. They are used for investigating the infi ltration process and the buffering capability of the bedrock to neutralise the groundwater and render it void of oxygen. The report for the in-fi ltration test will be completed in 2013.

Geophysical hole investigations were continued in the area of new drill-holes (OL-KR56, -57 and -57B) using methods selected as the standard, includ-ing, for example, optical and acoustical imaging and resistivity measurements. In addition, an extensive campaign of mise-à-la-masse measurements was implemented for the purpose of extend-ing the survey area concerned and com-bining the new results with the previous ones. The measurements will be contin-ued until early 2013. SAMPO monitor-ing measurements were also conducted in autumn 2012, and the results will be reported during 2013.

New TERO76 hole measurement equipment, developed by Posiva and the Geological Survey of Finland for measuring the thermal properties of bedrock, was put into production use in 2012. The TERO equipment is used for determining the thermal properties of bedrock (thermal conductivity, thermal diffusivity, volume thermal capacity) in drillholes. The TERO measuring equip-ment was used for measurements in drillhole OL-KR46 in the depth range of 103–480 m.

RESEARCH CONDUCTED IN ONKALOGeological mappingsIn 2012, the geological mapping of ONKALO progressed at the same pace as the excavation work. Geological map-ping of the fi rst phase (round mapping) followed in the immediate vicinity of the excavation work, and, as before, it was always conducted from beneath the re-inforced area under the previous round. In addition to measurements on large

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fractures and deformation zones inter-secting the tunnel, the bedrock surfaces were also systematically photographed during the fi rst mapping phase.

Geological mapping of the second phase (systematic mapping) also pro-gressed according to plans, following the progress of the tunnel excavation work. In 2012, the systematic mapping of the second phase included more tunnel floor mapping work than be-fore. Floor mapping work was mainly performed in the technical facilities of ONKALO at level -437 m, but also in the personnel shaft end at level -455 m. Previously, floor mapping has been performed in the research facilities of ONKALO, in the shaft ends and in certain locations with a smaller surface area, such as the bottoms of measure-ment weirs. All excavated surfaces of the two demonstration tunnels were also mapped. The four test deposition holes bored in demonstration tunnel 1 were introduced as a new type of subject for mapping work.

Drilling operationsDuring the year, pilot holes were drilled particularly in the surroundings of the demonstration area. Pilot hole ONK-PH20 (40 m) was drilled in February for the purpose of continuing demonstra-tion tunnel 2, ONK-PH19 (123 m) was drilled in parking hall 2 in May, ONK-PH23 (77 m) was drilled in June in the planned location of vehicle connection 5, and ONK-PH22 (88 m) was drilled in September for the purpose of extend-ing the tests on the RSC methods. Pilot holes ONK-PH26 and ONK-PH27 (23 and 20 m, respectively) were drilled in November in the area of the future dem-onstration tunnels 4 and 5. Of the above, only the tunnel of hole ONK-PH20 has been excavated; the other holes are included in the long-term monitoring regime, and the investigations regarding plug tunnel pilots are still in progress. In addition, six investigation pilot holes (ONK-PP379–384, 7 m and 8 m long) were drilled in demonstration tunnel 2 in November for test deposition holes.

In January, eight vertical holes of 7.5 to 10 m in depth (ONK-PP340–347) were drilled in investigation niche 3

around the last test hole for the instru-mentation of a heating test related to Posiva’s spalling experiment (POSE) phase III. In April and October, 30 short drillholes (ONK-SH22–49, ONK-SH151–152) were drilled in the fi rst section of the investigation niche for the purpose of investigating the excavation damage zone (EDZ) created by the ex-cavation work on the tunnel fl oor. The holes are about 1.5 metres long.

Four 10-metre holes were drilled at level -290 and 12 holes ranging from 5 to 10 metres were drilled at level -437 m for the purpose of expanding the micro-seismic network.

Grouting drillings continued at the inlet air shaft and the personnel shaft from level -290 m downwards, and a total of 33 grouting and control holes were drilled there during the year. In addition, 12 holes were drilled for the purpose of grouting the surface layer of the inlet air shaft.

Studies carried out in research and demonstration facilities and in other facilitiesThe studies related to construction and rock suitability classification (RSC) were continued in the demonstration facilities. Geological mapping was per-formed in the four test deposition holes bored in the fl oor of demonstration tun-nel 1 where the variation of rock types, the presence of fractures and infl ow of groundwater were observed. Leakage was observed in one hole, and a develop-ment work for the measurement method of the total infl ow into a deposition hole was started. Ground penetrating radar measurements and the suitability of the method for observing the continuity of structures was tested in the last hole of the tunnel.

Geological mapping of the first phase was performed in demonstration tunnel 2 as the excavation work pro-gressed. In that conjunction, the exact locations of large fractures and fracture zones cutting across the tunnel profi le were measured using a tachymeter and the rock surface was systematically photographed before netting the tunnel roof. The more detailed second phase of mapping followed a little later after

and for the roof it was done through the reinforcement wire meshes. Once the excavation of demonstration tunnel 2 had reached the length of 85 m, a pilot hole with the approximate length of 40 m was drilled from the end of the tun-nel, and Posiva’s standard investigations were performed in it for the purpose of more detailed characterisation of the rock suitability classifi cation and the planned extension of the tunnel. Once the tunnel had reached its fi nal length (about 105 m), surveys using ground penetrating radar were carried out in the tunnel for observing the continuity of both the excavation damage zone (EDZ) and fractures and fracture zones. The state of stress in the bedrock and the total volume of water leakage observed in the tunnel were also measured. The leakage measurements will continue and become more accurate in 2013. Six vertical pilot investigation boreholes were drilled in demonstration tunnel 2 in the planned locations of test deposition holes, and Posiva’s standard investigations were performed in the holes for the purpose of collecting information on the rock volume beneath the tunnel fl oor for use in rock suitability classifi cation.

Four new investigation pilot holes were drilled in the demonstration fa-cilities area. Two of the holes were drilled on the eastern side of the dem-onstration tunnels as part of the planned demonstration extension related to rock suitability classifi cation; the material obtained from the pilot holes will also be used for extending the detailed-scale model to the area. The other two pilot holes were drilled in late 2012 on the north-eastern side of the current facili-ties for the future demonstration tunnels 4 and 5. The plan is to construct a full-scale tunnel end plug, complete with instrumentation, in these demonstration tunnels as part of the deposition tun-nel plug demonstration (POPLU) to be implemented in the coming years. The holes were drilled in the future locations of the tunnels for the purpose of char-acterising the bedrock volume and for assessing its suitability before starting the excavation. Posiva’s standard pilot hole investigations either have been or will be performed in all four pilot holes.

14

In 2012, the geophysical investiga-tions in ONKALO mainly concentrated in the demonstration area and investi-gation niche 3. Geophysical pilot hole investigations were performed in holes ONK-PH19, ONK-PH20, ONK-PH22 and ONK-PH23 as well as in the six pilot holes of the test deposition holes to be bored in demonstration tunnel 2. Geophysical down-hole imaging was performed in the 16 investigation drillholes of 1.3 metres length associ-ated with the excavation damage zone investigations of investigation niche 3. EDZ measurements using ground pen-etrating radar, electrical resistivity to-mography (ERT) and hydraulic pressure tests were also performed in the same research area for the needs of excava-tion damage investigations. A limited down-hole geophysical measurement campaign was implemented in the four holes associated with the heating test in investigation niche 3 and in the fi ve investigation drillholes of investigation niche 5.

Ground penetrating radar investiga-tions were conducted on the walls and fl oor of demonstration tunnel 2 for the needs of rock suitability classifi cation and excavation damage investigations. EDZ measurements using ground pene-trating radar were performed in the fl oor of the parking hall of technical facilities in support of the excavation damage

investigations. In addition to the above, a trial investigation was also performed using low frequency ground penetrating radar on the walls of test deposition hole EH9 in demonstration tunnel 1.

In 2012, preparations were made in the rock mechanical investigation niche (investigation niche 3) of ONKALO for the continuation of the POSE in situ test associated with rock stress investiga-tions. During phase 3 of the test, a single investigation borehole of 1.5 m in diam-eter is heated until it breaks, and break-ing of the bedrock is monitored using acoustic emission equipment and strain gauges. The globally unique acoustic emission equipment allows detecting and locating, with exceptional accuracy, the breaking of bedrock behind the rock surface during the in situ test. The nature and extent of damage caused during the earlier phases of the POSE test were in-vestigated during 2012. The work for in-terpreting the results is still continuing.

The most signifi cant step taken in 2012 in the development related to rock mechanics was the development of the new LVDT (Linear Variable Differential Transformer) stress state measurement method and verifi cation of the func-tionality of the method in Äspö Hard Rock Laboratory jointly with SKB. Stress state measurements were also conducted in 2012 in several locations in ONKALO’s demonstration tunnels

using the developed method. In addition, an extensive stress state measurement campaign was implemented using an LVDT cell in the exhaust air shaft at levels -315 m, -360 m and -413 m. The measurements were used for investigat-ing the effect of deformation zones on the stress fi eld. It is expected that the measurement results will help form a better picture of the state of stress pres-ent at the disposal depth.

The detailed hydrogeological study (HYDCO) started in 2010 was contin-ued in the hydrogeological investigation niche (investigation niche 4) at chainage 3748. The objective of the study is to obtain information on the small-scale hydrogeological features of bedrock corresponding to the disposal depth, such as the hydraulic connections be-tween transmissive fractures. Investi-gation drillholes ONK-PP262 and -274 in investigation niche 2 were installed with multipackers for the small-scale in-terference test to be conducted in 2013.

In addition, hydrogeological data was collected from ONKALO by conducting fl ow measurements (PFL DIFF) in probe and pilot holes as well as in shaft grouting holes. Water infl ow mapping and measurements were car-ried out at regular intervals as the tunnel progressed. A more detailed description of these investigations is available later in this document in the section entitled Olkiluoto monitoring programme.

As the excavation work of under-ground facilities progresses, probe holes are bored in the tunnel profi le at about 20-metre intervals. Measurements related to water infl ow, water loss and fl ow rates, as well as water sampling are performed in the holes in accordance with separate plans. The probe holes are also measured with manual PFL equip-ment if the inlow exceeds 30 ml/min. All fl ow measurement results obtained from ONKALO are utilised when producing a more detailed hydrogeological model of the Olkiluoto bedrock.

A matrix diffusion test (REPRO) started in 2011 in ONKALO’s inves-tigation niche 5 at the approximate depth of 400 m. REPRO is aimed at establishing the retention properties of the bedrock representing the near-fi eld

Figure 3. Top: Drill core sample from the REPRO test investigation hole ONK-PP318 and its planned division between different studies. Bottom right: An image of micro-fractures in the sample, crested using the PIMA method at the Laboratory of Radiochemistry in the University of Helsinki. Micro-fractures are seen in the image as dark stripes and areas; the highest porosity is found in the darkest spots. The total porosity of the sample is 0.44%. A photograph of the sample is seen on the left. (images: University of Helsinki, Laboratory of Radiochemistry)

15

of the deposition holes. The results of the test will help assess the retention of radionuclides caused by matrix diffusion in a situation where the engineered bar-rier system is assumed to have lost its functional capability. Researchers from different organisations and universi-ties participate in the test. Nine short drillholes were drilled in late 2011 for the test. Drill core samples were taken from them for matrix pore water, per-meability, matrix diffusion porosity and retention studies to be conducted in the laboratory (Figure 3). Migration tests will be conducted in the investi-gation niche where the tracer, carried by both water and gas, is brought into contact with the bedrock. Preliminary testing of the water vapour diffusion test equipment was performed in 2011 at the opening of investigation niche 4. These tests were associated with the REPRO studies.

Tracer tests began in investiga-tion niche 5 in early 2012. This was the fi rst phase of the water phase fl ow test where a short pulse of radioactive tracers (HTO, 125I, 26Cl and 22Na) was fed into contact with the bedrock at a length of about two metres between the drillhole and the fl ow controller. The tracer started to come through about 100 hours after that. The penetration of the tracer was monitored until the end of summer 2012.

The purpose of the sulphate reduc-tion test (SURE) is to study the micro-biological reduction of sulphates into sulphides and the energy sources used by the microbes in the process, particu-larly the utilisation of methane and the microbial strains capable of it. The test series started in 2010 (SURE 1) was continued in 2012 (SURE 2) by connect-ing fl ow/reaction cell arrays to drillhole ONK-KR15 (Figure 4) and by circulat-ing the methane-containing groundwater of the hole in the equipment for about two months and by planting at the same time in the cell array a microbial strain compatible with the conditions. The equipment was sealed and taken to the laboratory facilities of Micans AB where the test was continued by activating the microbial strains with water containing SO

4. The progress of the test was moni-

tored chemically and microbiologically for 106 days. Microbiological analyses were performed for the fi rst time on the test waters and on the biofi lm clinging to the substrate (crushed rock from the drillhole). The report of the SURE 1 test series – which was conducted in groundwater containing SO

4 by feeding

the microbial strains with CH4 and H

2

gases – was completed in 2012, while the SURE 2 test series will be reported during 2013.

MODELLINGOlkiluoto Site Description 2011, a re-port integrating and compiling the site description, was published in late 2012. This is version number four of the Olkil-uoto Site Description. The geo-scientifi c modelling work of the Olkiluoto survey area is coordinated by the Olkiluoto Modelling Task Force (OMTF). The purpose of the modelling work is to produce a geological, hydrogeologi-cal, geochemical and rock-mechanical description of Olkiluoto. In addition, the work in 2012 also concentrated on producing several background reports for the modelling work.

Geological and geophysical modellingThe site description published in late 2012 presented version 2.1 of the geo-logical model. The 3D description of the bedrock was further updated to version 2.3 with respect to brittle fracture zones and rock types. This update was not re-ported separately; instead, it was passed on to further users as a memorandum.

The update of the geological model has primarily consisted of changes made on the basis of new material and inter-pretations. The 3D images of the rock type model and ductile deformation have in the current version been devel-oped to be consistent with the bedrock map using investigation trenches, map-ping operations and drilling operations. The history of ductile deformation and the chemical and mineralogical al-teration processes are now described in greater detail in the site description, and the understanding regarding the history of brittle deformation has become more specifi c as the deformation indicators have been studied. The updated geo-logical discrete fracture network model was reported in the summer as a Posiva report (POSIVA 2012-27).

Figure 4. The equipment used in the SURE test in a research container in ONKALO at the approximate depth of 400 m. The fl ow cell arrays (3 arrays) are connected to ONK-KR15, and microbial strains are planted from the groundwater circulating in the equipment into the crushed rock with which the cells have been fi lled. (photo: Karsten Pedersen)

16

In 2012, the geological modelling work concentrated on detailed-scale modelling carried out in the demonstra-tion facilities of ONKALO mainly for the purposes of Rock Suitability Clas-sifi cation (RSC). Detailed-scale model-ling has concentrated on characteristics signifi cant for rock suitability, such as extensive and transmissive fractures and deformation zones. The model and the suitability assessment of facilities based on it were updated on several occasions as the construction of demonstration facilities and studies progressed. A pre-liminary description of detailed-scale modelling is provided in a RSC report (POSIVA 2012-24). Comprehensive reporting on the modelling methods and results is scheduled for 2013.

Lineament interpretation and reportingThe lineament interpretation forming part of the investigations regarding the bedrock in the Olkiluoto area was supplemented with new geophysical aerial measurement materials produced in 2008 and 2009. The lineament in-terpretation work was performed by visually analysing different geophysi-cal map versions and by picking out the geometry of lineaments from them. In addition, quantitative interpretation work was performed for defi ning the dips of the lineaments and the locations of their contacts. The interpretation results were combined with the earlier lineament model based on geophysical, topographic and sea depth data. The combined interpretation has a total of 200 lineaments which form the basis for the geological model of the Olkiluoto area. The supplemented lineament inter-pretation will be published as a Posiva report in 2013.

HydrogeologyIn 2012, surface hydrogeological mod-elling in Olkiluoto concentrated on assessing the impacts of ONKALO, on producing short-term forecasts and particularly on determining the infl ow water limits in connection with model-ling the long-term impacts of infl ow in ONKALO. Salinity was added to the model in 2011, and the informa-

tion was utilised in 2012 in the model-ling work related to determining the limit values. As in previous years, the model was also used for modelling the impacts of a long-term infi ltration test implemented in Olkiluoto. In addition, the work for modelling the surface hydrology included estimation of the hydrological water balance associated with the Korvensuo reservoir and the long-term future developments in the surface hydrology of the Olkiluoto area. The Korvensuo reservoir was built in the 1970s to produce process and tap water for power plant operations. Most of the total volume of water discharged from the Korvensuo reservoir does not infi ltrate very deep into the bedrock but fl ows instead horizontally along shallow routes away from the reservoir area and is discharged into soil layers. In 2012, a leakage was detected in investigation trench OL-TK19 excavated on the west-ern side of the basin. It is one indication of the existence of connections near the ground level predicted by the surface hy-drology model. Water balance measure-ments indicate that the total volume of water discharging from the Korvensuo reservoir to the surrounding environ-ment has during 2010–2011 been around 150–180 litres a minute. According to modelling, the water volume has dur-ing 2010−2011 been about 110–120 litres a minute, dividing roughly as fol-lows: about 30 l/min is a natural value before the construction of ONKALO commenced, the impact of ONKALO infl ow is about 5−10 l/min, while the impact of raising the water level in the reservoir is about 70−80 l/min (the water level was raised permanently by about 1 m in 2007). According to the model, the volume of water infi ltrating from the Korvensuo reservoir deep into the bedrock was about 3 l/min before ONK-ALO and currently about 15−20 l/min (of which about 5−10 l/min is therefore attributable to ONKALO).

Reporting of the update to the bed-rock groundwater model produced in 2011 was fi nalised in early 2012, both as a part of the site model report (PO-SIVA 2011-02) and as a working report of the hydrogeological fracture network model. Hydrogeological modelling also

produced calculation results for devel-oping the rock suitability classifi cation process and for use as initial data for the radionuclide migration modelling work derived from the safety case. The results indicate that the infl ow water quantities in the modelled deposition holes are mi-nor; for example, the infl ow water limit of 0.1 l/min is only exceeded in 1.6% of all deposition holes, and only 12% of the deposition holes exceed the infl ow value of 0.01 l/min. The infl ow water volumes are particularly limited by the sparse structure of the hydraulically connected fracture network. Therefore, the infl ow water quantity also seems to depend on the distance of the deposi-tion hole from major rock fractures. The impact distance was estimated at about 20 metres from rock fractures with a minimum size of 150 m.

Hydro-geochemistryThe hydro-geochemical research ac-tivities included fi nalising the hydro-geochemical modelling part of the Olkiluoto Site Description. The model describes the past hydro-geochemical developments, origin and retention of groundwater types, distribution of sa-linity, chemical buffering capacity of the groundwater system and changes in the groundwater conditions caused by ONKALO. The site description includes the fi rst model describing the geochemical developments in Olkiluoto during a period of millions of years. This paleo-hydro-geochemical model is also used for studying the fl ow behaviour of groundwater as a result of past environ-mental changes. Flow simulations were carried out to support the model. They were used for investigating the diffu-sion between groundwater in bedrock fractures and matrix pore water in rocks and the development of salinity and interaction times, as well as for further specifying the opinion on the structure of matrix porosity. In addition, supple-mentary geochemical model analyses were performed regarding the behaviour of dissolved sulphides in Olkiluoto’s groundwater conditions. The recharge test results have been simulated by means of reactive migration modelling.

17

Rock mechanicsIn 2012, the rock mechanical modelling work concentrated on the pre-modelling of phase 3 of the POSE test, on the basis of which the test to be implemented in 2013 has been planned and equipped. In addition, backward calculations have been performed and results reported re-garding the earlier phases of the POSE test.

The work for compiling the Rock Mechanical Model (RMM) of Olkil-uoto continued in 2012 by adding to the model research data accumulated during earlier years and by developing the usability and visualisation of the model so that it could be more exten-sively deployed. The purpose of this modelling work is to study, among other things, the effect of fracture zones on the orientation or magnitude of stress fi elds. The modelling work will be reported in separate reports.

Surrounding environmentabove groundIn addition to monitoring the surround-ing environment above ground (see the section entitled Monitoring pro-gramme), biosphere research campaigns were implemented in 2012: Samples were collected of the shore and water vegetation and sediments in Olkiluoto and two lakes in Eura and Eurajoki, and the work initiated in 2010 for supple-menting the data on swamps located outside Olkiluoto was continued with supplementary vegetation and peat sur-veys at the Lastensuo swamp in Eura-joki. A pit was dug with an excavator in Olkiluoto as part of the soil studies, and the pit was used for mapping the layered structure of the overburden and for taking laboratory samples in order to determine different parameters in-cluding the grain size distribution and abundance of different elements. Posiva also participated in the nationwide archi-pelago birdlife monitoring programme on small islets and islands far out on the Olkiluoto sea area.

BEDROCK CLASSIFICATIONIn 2012, the meaning of the RSC con-cept was extended to cover, instead of mere Rock Suitability Criteria, the entire

rock suitability classifi cation method, and the new meaning of the abbreviation was defi ned to be Rock Suitability Clas-sifi cation. Small changes were made in 2012 to the suitability criteria approved in late 2011, mainly related to reducing the ambiguity of the wording, and the work for developing the practical appli-cation and verifi cation of the criteria and for developing the process used for rock suitability classifi cation continued as the construction of demonstration facilities advanced. The particular issues raised in connection with the demonstration facilities were related to the water infl ow volume to be allowed for the excavated tunnel. These issues were considered and discussed, for example, in a two-day workshop meeting regarding the backfi lling of deposition tunnels. The deliberations regarding issues related to large fractures were also continued, among other things, by planning an additional analysis for evaluating the susceptibility to deformations related to possible post-glacial earthquakes. The analysis is based on numerical model-ling of the stability of brittle structures in the Olkiluoto bedrock.

As the construction of demonstration facilities progressed, the rock suitability was classifi ed on several occasions. The last rock suitability classifi cation for demonstration tunnel 1 was performed in November when the fi nal suitability of the test deposition holes was deter-mined on the basis of investigations car-ried out in the holes and the subsequent update of the small-scale model; three of the four test deposition holes met all suitability criteria set for the holes and were classifi ed as suitable. The suitabil-ity of demonstration tunnel 2 was classi-fi ed in June following investigations in a pilot hole bored in the end section of the tunnel and in August after investiga-tions following the completion of tunnel excavation work. The locations of the test deposition holes to be placed in the tunnel were determined on the basis of the latter classifi cation, and vertical pilot holes were drilled in these locations in November for the purpose of verifying the suitability of the selected locations. The rock suitability classifi cation work with respect to demonstration tunnel 2

will continue in 2013.A report (POSIVA 2012-24) describ-

ing rock suitability classifi cation was published in late 2012. The report pres-ents, among other things, the approved suitability criteria and the development and testing work leading to them, de-scribes the suitability classification method and its application in connection with the construction of demonstration facilities and presents a summary of the geological properties of Olkiluoto at the disposal depth and of the general suitability of the site for fi nal disposal.

Monitoring programme

The changes possibly caused by the construction of ONKALO have been monitored with a programme (OMO) established for the purpose (Posiva 2012-01). The purpose of this monitor-ing programme is to produce informa-tion on the state of the disposal site and on the environmental impact of Posiva’s operations in Olkiluoto. The programme includes rock-mechanical, hydrological and hydrogeochemical monitoring and monitoring of the surface environment and foreign materials. In addition, moni-toring of the behaviour of the engineered barrier system has been added to the scope of the programme. The results of monitoring studies are published separately for each discipline as part of the series of Posiva’s working reports. Monitoring of the engineered barrier system is still at the development stage, which is why the related development and research results will be reported in connection with other reporting re-lated to the engineered barrier system. An overview of monitoring activities related to the disposal site in 2012 is shown below.

ROCK MECHANICSIn 2012, rock-mechanical monitor-ing continued as in previous years. Micro-seismic data was continuously analysed and monitored. Most of the events detected by the station network are excavation blasts in ONKALO. The other seismic events are typically caused by construction work either above or below ground.

18

GPS measurements in Olkiluoto and its surrounding area were taken in the spring and autumn. Precision levelling of the fi xed points in the bedrock was also performed using the GPS points in the vicinity of ONKALO and the VLJ repository as well as over the Olkil-uodonsalmi straits. The purpose of these measurements was the same as that of the micro-seismic measurements, i.e. to further reinforce the opinion regarding the stability of the Olkiluoto bedrock and to assess the variations in the land uplift rate in Olkiluoto and its neigh-bouring areas. The precision levelling results reported in 2012 indicate that the small movement detected in 2007 in the Olkiluodonsalmi straits has steadied. Expansion and development of the GPS station network began in 2010, and it has been continued by connecting electricity to the existing pillars and by constantly installing measurement antennas. The development work will both expand the observation area and improve the accuracy of observations.

Reading of the two extensom-eters installed in autumn 2011 in the technical facilities area of ONKALO has continued. The extensometers are used for monitoring the deformation

of two pillars located between halls of east-west orientation. The forecast and actual dislocations have been of the order of 1–2 millimetres. In addition, dozens of state of stress measurements were performed in the exhaust air shaft of ONKALO between levels -290 and -437 m as well as in the demonstration facilities during 2012; they produce in-formation on the fi eld of stress for the purpose of monitoring it.

HYDROLOGYHydrological monitoring continued in 2012 mainly following the same programme as in 2011. The biggest change compared to the early stages of ONKALO construction work has been the change of focus from monitoring the fl ow conditions to monitoring hydraulic heads in drillholes.

Groundwater level observations were made in both shallow groundwater tubes and boreholes and in deep open drillholes using manual methods once a month. A few water level reference holes and shallow holes in the infi ltra-tion experiment area have also been monitored using automatic level sen-sors. The monitoring of hydraulic heads took place using an automatic pressure

monitoring network of multi-packered drillholes (GWMS). The online moni-toring of data worked as planned in 2012, and the processing and analysis of data was further developed. At the beginning of 2012, corrections for earth tide and atmospheric pressure effects were introduced in addition to the cor-rection for other natural effects (ground-water and sea level fl uctuation) made to drawdown determinations.

By the end of 2012, a total of 28 deep drillholes had been installed with multi-packers and added to the monitor-ing network. The packers of drillholes OL-KR11 and OL-KR28 were repaired and a new hole OL-KR51 was packed-off in 2012. The major transmissive HZ20 structures were penetrated by the ONKALO access tunnel in late 2008 and at the turn of 2008–2009. During 2009−2012, the same structures have of-ten been penetrated by grouting holes in the shafts. In addition, exhaust air shaft ONK-KU2 was raise bored between the depths -290...-437 in October 2011. As in previous years, the impacts of leak-ages related to the main hydrogeological zones on groundwater pressure were monitored and analysed during 2012.

A quarterly memorandum was com-

Figure 5. Result of water infl ow measurement performed on 18 November 2012, 36 l/min (of which 3.4 l/min is from the exhaust air shaft), up to ONKALO access tunnel chainage 4580 and exhaust air shaft level -437 m.

19

piled during 2012 as planned, discussing the results of groundwater level and hy-draulic head measurements and analys-ing the short-term impacts of other fi eld events and ONKALO construction work on hydraulic heads.

Furthermore, the following param-eters were monitored: fl ow conditions (Posiva Flow Log) in open holes, water conductivity both in deep drillholes (Hy-draulic Testing Unit) and short boreholes and groundwater tubes (SLUG method), the salinity of groundwater (EC), runoff surface water volumes, seawater levels and infl ow in ONKALO. Transverse fl ow measurements were performed in 2012 for the fi rst time offi cially as part of the monitoring programme when re-peat measurements were done in holes OL-KR31, -33, -35 and -36. Of the parameters included in the hydrologi-cal monitoring programme, the runoff surface water volumes, rainfall (includ-ing snow), thickness of ground frost and infi ltration are reported in the annual environmental monitoring report.

The monitoring activities in ONK-ALO continued in 2012 with measure-ments of total inflow approximately once a month. The measurements are taken, as far as possible, for the entire length of the tunnel and from measur-ing weirs, the total number of which in use at the end of 2012 was nine (at chainages 208, 580, 1255, 1970, 3003, 3125, 3356, 3941 and 4580). The mea-suring weirs are used for metering the volumes of accumulated water as well as its chemical properties (pH, conductiv-ity). Water infl ow in the shafts was also separately measured using collection chutes at the bottom of shaft sections. The HZ20 structures are located be-tween measuring weirs 3125 and 3356. The average total infl ow in ONKALO has increased from the 20 litres/min in 2008 to 33 litres/min in 2009. The main reasons for this are the penetration of HZ20 structures with the access tun-nel and the raise boring of three shafts to level -290 m. The infl ow in the ac-cess tunnel has been the same as in the previous year (an average of 34 l/min in 2012 up to chainage 4580), because there were very few transmissive frac-tures or structures in the access tunnel

section excavated during 2010−2012. The measurements taken during the year indicate that the infl ow in the exhaust air shaft raise-bored in October 2011 (level range -290...-437 m) has on average been about 3.5 l/min. The total infl ow of ONKALO has during 2012 been on average about 37 l/min (a representa-tive measurement result obtained on 18 November 2012 is shown in Figure 5). A visual mapping of infl ow points covering the entire length of the tunnel was carried out once in 2012 in order to identify the location of leaking fractures and zones and to monitor any changes taking place in them. In addition, a monitoring fl ow measurement was per-formed in ONKALO in characterisation hole ONK-KR13.

HYDROGEOCHEMISTRYIn 2012, the hydrogeochemical moni-toring programme of Olkiluoto was, in the main, implemented in line with the sampling plans. The main focus of the studies was on monitoring the changes in salinity and phenomena associated with the reduction of sulphates, which were both observed during previous years, particularly in the main fracture zone at the depth of 100–500 metres. Furthermore, the studies also focused on deep (> 500 m) transmissive structures. Comprehensive studies were also car-ried out regarding the monitored objects in ONKALO.

Changes have been observed in the groundwater chemistry in the Olkiluoto region; these include the observation that bicarbonate-containing water from the top layers of bedrock has migrated deeper down to the monitoring points as a result of the hydraulic gradient created by ONKALO. Hydrological structures HZ20A and B are drawing groundwater strongly towards ONKALO, which ei-ther causes dilution or increased salinity depending on whether the monitored drillhole is open or installed with multi-packers. Dilution usually takes place in zone HZ20A, which has a connection to the ground level. Instead, the moni-tored objects in zone HZ20B have been found to become diluted if the drillhole is open and to sometimes increase in salinity if the drillhole is installed with

multi-packers. The cases of increased salinity were found to have steadied in 2012. Furthermore, the failure of the multi-packers in drillhole OL-KR22 in summer 2009 has enhanced the fl ow on bicarbonate-containing water to zone HZ20. This was already detected in the samplings of 2010, and it can still be seen in the results for 2012. A similar chemical phenomenon is also observed as a result of the failure of multi-packers in drillhole OL-KR28 which occurred in 2011. However, the observation has been made in the monitoring objects of the HZ21 structure that the high hydrau-lic gradient caused by ONKALO has not yet had any marked effect on deep saline groundwaters. The most obvious single change in monitoring subjects was ob-served in drillhole OL-KR1 at the depth of 311–336 m where a marked increase in salinity has taken place. This monitor-ing subject is located in the impact area of structure HZ056 which has a connec-tion to ONKALO. This connection may explain the increase in salinity over the survey interval. This is why the changes of salinity in drillhole OL-KR1 will be monitored more closely.

The diluting effect of the Korvensuo basin on groundwater has been observed in particular in shallow groundwater pipes and rock holes in its vicinity. Groundwater samples have been taken in ONKALO according to the pro-gramme, primarily from groundwater stations. Ten groundwater stations were regularly monitored during 2012. Both groundwater chemistry studies and microbiological studies have been conducted in these holes, and the re-sults have corresponded very well with the natural state of groundwater with only a few exceptions. These excep-tions include the increasing sulphate concentration that was already detected during 2011 and now also during 2012 in sampling from a groundwater station (ONK-PVA9) located at the disposal depth as well as in water sampling from the fracture zone now being observed (ONK-RV4385). It has been deemed that ONK-PVA9 and ONK-RV4385 are associated with vertical structure BFZ045. These changes are probably also caused by the hydraulic gradient

20

created by ONKALO. The studies on the immediate im-

pacts of ONKALO construction work continued with water sampling from fractures and fracture zones leaking water and from waters pumped from ONKALO. The construction of ONK-ALO, in particular shotcreting, causes from time to time considerably high pH values (10–12) in waters pumped from ONKALO. However, the values are rap-idly neutralised in the drain ditch, and no harmful effects on the environment have been observed.

SURFACE ENVIRONMENTThe work of monitoring the surface envi-ronment in Olkiluoto continued in 2012, by and large in line with the planned re-search programme. The regular research activities include the monitoring of the state of forests in Olkiluoto, a surface water sampling programme and moni-toring of game stock through interviews with hunters. Laser scanning of the shallow water areas in the southern and northern shores of Olkiluoto island (so-called green lidar) was implemented in September. In addition, Posiva monitors the environmental surveys commissioned by TVO and other parties.

FOREIGN MATERIALSThe monitoring and control of foreign materials is part of Posiva’s monitoring

programme. Foreign materials refer to all those materials and substances used for constructing ONKALO that are not part of the disposal system. In 2012, a total of 63 applications related to foreign materials or proposals for changing their earlier area of application were pro-cessed. The use of each foreign material is described in a separate document that has a safety data sheet and instructions for use of the subject material appended to it. The details have been recorded in the materials manual.

During 2012, the quantities of con-struction materials used were monitored in compliance with the agreed practice. The records submitted by contractors allow calculating the annual usage of cement both for grouting and for shot-creting. The quantities of explosives, paints and different metal bolts used in construction work are also monitored.

The work for analysing explosive residuals left on the rock surfaces of ONKALO after excavation work contin-ued in 2012. The results of the analysis were used for estimating the quantity of explosive residuals present in a 10 cm thick layer of rock. The molar con-centrations of the substances as moles per litre were determined by assuming that all compounds would dissolve in the entire volume of ONKALO. The work for assessing the potential impact of these concentrations on long-term

safety began towards the end of the year. The results from the solubility study

regarding Densiphalt, the paving mate-rial foreseen for ONKALO’s access tunnel, were obtained during 2012. The total concentrations of harmful metals were analysed from the samples using a through-fl ow test compliant with stan-dard CEN/TS 14405 and extraction with aqua regia, while PAH, PCB and min-eral oils were analysed by pyrolysis. The harmful elements and anions listed in legislation as well as dissolved organic carbon, pH and conductivity are deter-mined from the test solutions. The total concentrations and solubility values were compared with the limit values set out in the relevant decree. The solubil-ity values were very low, which would indicate that Densiphalt is suitable for paving the vehicle path. The paving will be removed when the facility is sealed off, but the service life of the paving is about 100 years, which is why it will be investigated in the future whether its use could cause harmful effects on the long-term safety of ONKALO.

The investigations regarding ONK-ALO’s blasted rock storage area and the outlet were enhanced in 2012. The purpose of these investigations is to establish whether any oil from the ma-chines used in ONKALO or explosive residuals have ended up in the blasted rock storage area or the outlet.

21

Plant design

Encapsulation plant

In 2012, the encapsulation plant design work concentrated on the preparation of documentation for the construction licence application. The documentation was completed at the end of the year. The specifi ed requirements of STUK’s Regulatory Guides on nuclear safety (YVL Guides) currently being updated were taken into account in the design work to the extent that they were al-ready known.

In the systems design work for the encapsulation plant, the updates of the preliminary plans regarding the fuel handling cell (Figure 6) were completed;

The nuclear waste facility consists of an encapsulation plant to be constructed at ground level, other auxiliary buildings and structures at ground level and the under-ground disposal facility. The construction work for the encapsulation plant and repository will begin when the construction licence has been granted. The operations of the facility are scheduled to start in the early 2020s after the operating licence has been granted.

The spent nuclear fuel brought from the interim storage is packaged into canisters in the encapsulation plant

and transferred to the disposal facility in a lift. The current plans involve excavation of the repository on one level at -400...-450 m. Access to the underground disposal facility is through the access tunnel and shafts. Deposition holes will be bored in the fl oors of the deposition tunnels for inserting the canisters. The canisters will be completely surrounded by bentonite blocks that will swell considerably when becoming wet. The repository will be expanded as the disposal operations progress by excavation of more disposal and central tunnels.

the most important update concerns the plan for the fuel handling machine. At the same time, the systematic work for determining the requirements concern-ing the handling machine was completed with a view to supporting the detailed design and procurement of the mecha-nism in the future. The intention is to utilize the developed procedure also for determining the requirements of other encapsulation plant systems. In addition, the update of the plan for the remote controlled mover for disposal canister transfer was completed. The mover will be used for transferring the canisters to the canister lift at the encapsulation plant and from the lift

at the disposal depth. The mover will be based on a commercially available application which can be modifi ed so that the special requirements regarding canister transfers can be met.

The updated plans for the ventilation and cooling systems of the encapsula-tion plant were completed, and they were used as the basis for the construc-tion licence application documentation. Principal plans and system descriptions were also produced of the plant’s radia-tion measurement systems.

Preparations also continued for initi-ating the implementation planning phase in the encapsulation plant design work. Main drawings of the encapsulation

22

plant were completed for the construc-tion licence application and for a basis of further design and planning work in-volving other fi elds of technology. The construction engineering dimensioning of the plant was also updated to corre-spond to the current plant design.

Disposal facility

In 2012, the design work for the disposal facility also concentrated on producing the construction licence application documents. Layout plans of the reposi-tory were produced for a fuel quantity of 9,000 tU taking into account the latest bedrock research data and other restric-tions regarding the layout.

The plans for the canister storage facility for completed canisters, forming part of the disposal facility, were supple-mented, and the cooling system of the storage was designed. The canister stor-age is situated in conjunction with the technical rooms of the disposal facility, at the bottom of the canister shaft. The storage has been dimensioned so that the canisters for one deposition tunnel can be prepared ready to wait for dis-posal, thus allowing an optimally quick disposal operation for one of the open deposition tunnels.

The work for verifying the perfor-mance of the shock absorber planned at the bottom of the canister shaft were continued with the planned test where an object with a mass of about 75 kg collides with the dampening material at a speed corresponding to its free fall ve-locity. More material tests were carried out in order to establish the parameters of the material model of Leca® gravel investigated for the dampening mate-rial so that the optimal material could be found. At the same time, an accident scenario was analysed where the canis-ter being installed accidentally falls into a deposition hole lined with bentonite. The assessments of both fall situations indicate that the canister will survive the accident situation intact. The mate-rial investigations regarding the shock absorber to be installed at the bottom of the shaft will be continued with a view to optimizing its dimensions.

In the systems design work for the

Figure 6. Fuel handling cell in the encapsulation plant. The canister docking station is seen in the front, the drying stations on the left, with the transport cask docking station on the right. The fuel handling machine is at the top.

disposal facility, updating of the facil-ity’s electrical system plans was com-pleted. In addition, the fi re simulations and analysis of the performance of ven-tilation system of the disposal facility continued using the earlier developed APROS model.

Installation and transfer techniques

In the development work for installation and transfer techniques, the manufactur-ing of phase 1 of the canister transfer and installation vehicle prototype began. The vehicle will be completed during 2013. In the fi rst phase, the work will concentrate on verifying the functional-ity of canister installation equipment and on demonstrating compliance with the tight installation tolerances with practi-cal installation tests.

The manufacture of the bentonite

block transfer and installation vehicle prototype is also in progress. The challenge with this vehicle is the tight tolerances in the installation of the bentonite buffer, necessary for achiev-ing the straight bentonite-lined instal-lation space required for installing the canister. The device will be completed during 2013.

The design work for the automated backfi ll block installation device began in 2012 with conceptual design work where the operating principles of the device were developed. After the con-ceptual phase, the design work will con-tinue with implementation planning for the prototype. The intention is to use the device for installing the backfi ll blocks and the pellets to be installed between the blocks and the bedrock. The chal-lenges are the required installation ac-curacy of the blocks and the suffi cient

speed of installation.

23

The nuclear non-proliferation control by Posiva is based on fulfi lment of the obligations set out in the legislation and international agreements governing nuclear non-proliferation controls. Po-siva has produced a safeguards control manual that describes the control during the construction phase of ONKALO. In its current form, the manual covers the period during which the construction licence application for the encapsulation plant and the disposal facility is being processed. The manual will be supple-mented as required during the construc-tion phase of the nuclear facilities. For the disposal operations, the manual must be supplemented to cover the nuclear material accounting and reporting as

Control of nuclear materials and nuclear non-proliferation (Safeguards)

well as control of the repository, which will all be Posiva’s responsibility. A safeguards plan of control by Posiva during the construction and disposal operations was submitted as an appendix to the construction licence application.

Posiva’s safeguards manual defi nes the preliminary, actual and monitoring data concerning ONKALO which are reported three times a year to STUK. In addition, STUK carries out inspections, including the inspections of the ONKA-LO rock facilities and periodic inspec-tions of the entire safeguards control system. In 2012, STUK performed four inspections of nuclear non-proliferation control measures, one of them as a joint inspection with IAEA and the European

Commission. No objections concerning the safeguards control of ONKALO were raised in these inspections.

The control and monitoring of ex-cavation work in underground rock facilities is based on the requirement to demonstrate that ONKALO does not include any facilities which are not in-dicated in the design data. The control produces as-built images describing the excavation and construction work carried out in each four-month period. The as-built images are supplemented by laser scanning images showing all of ONKALO’s contours with a high degree of accuracy. Monitoring makes use of the micro-seismic station network built in Olkiluoto; the surveillance data of the network provides up-to-date in-formation about blasting in Olkiluoto and in the nearby area. This system has proven to be a good method for moni-toring the excavation operations from the outside (Figure 7). The network of micro-seismic stations will be expanded as required for improving the position-ing accuracy. In 2012, the station net-work was expanded by installing a local network in the ONKALO shafts area at levels -290 and -437 m.

Figure 7. ONKALO excavation blasts located by the network of micro-seismic stations in 2012. Excavation work has mainly been performed in the demon-stration area, bottom part of the access tunnel and in the shaft junctions at level -455 m. The circles indicating the blast locations are blue for blasts in the fi rst half of the year and red for early sum-mer, after which no excavation work has been done. The ONKALO excava-tion plan is shown in yellow. (picture: Marianne Malm, ÅF Consult Oy)

24

Disposal system

Underground Openings

The work included in the Underground Openings task complex in 2012 in-volved the implementation of demon-stration facilities together with boring of test deposition holes, grouting and reinforcement, as well as implementa-tion of excavation damage zone (EDZ) investigations in investigation niche 3.

The fi rst four test deposition holes were bored in demonstration tunnel 1 using the Sanna boring rig in early 2012 (Figure 8). The boring of test holes and the removal of drilling sludge were suc-cessful from the technical point of view. The dimensions of the holes (such as depth and straightness of the hole) fell a little short of the set targets. The bor-ing instructions will be improved for the next test deposition holes in demonstra-tion tunnel 2.

The design of demonstration facili-ties was implemented as normal design work as part of the design work for the rest of ONKALO. Likewise, the tunnels

The disposal solution foreseen for the spent fuel pro-duced by TVO and Fortum is originally based on the KBS-3 solution developed by Svensk Kärnbränslehan-tering. The spent fuel bundles inserted into copper-cast iron canisters are placed hundreds of metres deep inside the bedrock. Compressed bentonite blocks are placed in the deposition holes between the rock and the canister. When the disposal operations are fi nished, all excavated facilities and access routes to the repository are backfi lled and sealed off.

The canister, bentonite and bedrock form multiple barriers, backing each other up, against the release of radioactive elements. The copper outer of the canister has excellent resistance against groundwater-induced corrosion, and the cast iron exterior ensures mechanical durability. Bentonite restricts the access of groundwater to the canister surface and protects the canister from minor bedrock movements. The conditions surrounding the canister deep inside the bedrock will remain stable for long periods of time. The bedrock also protects the deposited fuel from external interference.

Figure 8. Depo-sition boring rig in demonstration tunnel 1. The tem-porary cover on hole ONK-EH7 is shown at the front.

25

were implemented as part of the normal construction activities.

The actual grouting work performed as part of the silica grouting develop-ment work undertaken in 2011 in dem-onstration tunnel 2 took place in 2011, but the results were analysed and report-ed in 2012. Posiva’s working report on the development work will be completed in 2013. Silica grouting has been further developed at curve ONK-TT-4366. The grouting work is still in progress, and its results will be reported later.

As part of the reinforcement, devel-opment work for bolt grout with a low pH value for use at the disposal depth was undertaken during 2012.

Posiva has been doing EDZ-related research work for years, ever since the start of the excavation of of the ONK-ALO. First phase of the EDZ-related hydrological investigations began in 2012 in investigation niche 3 (Figure 9). In this fi rst phase, holes about 1.5 m deep were drilled in the fl oor for test-ing the geophysical and hydrological measurement methods developed for in-vestigating low groundwater fl owrates. The methods were found functional, and

Figure 9. EDZ investigations in investigation niche 3.

the measurements will be continued in spring 2013 in the same investigation niche. The purpose of the measurements is to determine the hydraulic properties of the EDZ and to use the thus obtained values for long-term safety modelling. The results will be reported later as part of Posiva’s report series.

The canister

The canister design documentation was updated during 2012 to correspond to the results of completed research and development work and to the require-ments set for the background material of the construction licence application, as well as on the basis of comments re-ceived for the documentation during its draft stage. New knowledge was gained of the behaviour of canister materials during manufacture, of the long-term behaviour of materials under strain as well as on the capability of structural materials to withstand material defects under load. New knowledge has been gained of the residual stresses in the cast iron insert and the EB weld in copper, as well as of the fracture toughness of

cast iron and the development of de-formation and creep elongations in the copper overpack and of the relaxation of stresses under the expected temperature and loading conditions of the canister in the long run. The additional information constitutes a signifi cant confi rmation of the earlier opinion that the canister system is capable of meeting the set re-quirements. The results were published as a canister design report.

The continuous development of nuclear fuels used in nuclear power stations towards higher degrees of en-richment and higher burn-up values has caused a continuous need to analyse in canister design work the subcriticality of the canister structure in such rare situ-ations where highly enriched but very little or not at all spent nuclear fuel has to be placed in an individual canister. The canister must remain subcritical with a suffi cient certainty in such cases, even if water penetrates in the canister. The analyses show that the situation is under control even with the new fuel types when suitable screening is implemented when selecting the fuel assemblies to be encapsulated and when exception-

26

ally reactive assemblies are placed in separate canisters.

The main dimensions of the canisters have remained constant for a long time, but the detailed clearances and dimen-sional tolerances have still been fi ne tuned. Posiva also participated in SKB-Posiva cooperation projects during the year for determining the requirements regarding the integrity and handling of canisters.

CANISTER MANUFACTURE The development work regarding can-ister manufacture continued in coopera-tion with SKB in 2012. The studies on the copper canisters manufactured in 2011 using the pierce and draw method were completed in 2012, and the work for optimising the manufacturing pro-cess continued. Three copper billets were cast for use in copper canister manufacturing tests using the pierce and draw method. In addition to veri-fi cation of the qualitative properties of the material, copper canister material was produced for demonstration tests in the pierce and draw manufacturing test, while manufacturing experience was also gained. The copper canister manufacturing tests went according to plan, but the destructive material tests of the canisters are still in progress. The actual NDT inspection was performed using ultrasound and eddy current tech-niques in SKB’s canister laboratory in Oskarshamn. In addition, the tubes were visually inspected using recording cam-era techniques. The inspections revealed a few surface defects but no internal de-fects. One crack in the exterior surface near the bottom was detected in one canister; it is still being investigated. Otherwise, the tubes showed in places mostly variations in attenuation, prob-ably caused by variations in grain size.

The development work for a BWR-type insert intended for spent fuel from OL1 and OL2 continued in Finland. Three BWR inserts were manufactured in 2012 (I69, I70 and I71). The require-ments regarding inserts were met with regard to mechanical properties and micro-structure. The development work regarding the manufacturing process concentrated on meeting the straightness

requirement of the tubes of the steel cas-sette and on the possibility of gauging the steel tubes after casting. At the same time, work also concentrated on opti-mising the steel cassette manufacturing process. The straightness requirement set for the fuel channels of the steel cas-sette was met for insert I70. The insert also met the requirements regarding surface quality, mechanical properties and micro-structure. The inspections of the last cast BWR insert (I71) are still in progress. The NDT inspections of the year’s fi rst insert (I69) have been com-pleted. They revealed various defects: spot defects which are not thought to be signifi cant to the strength of the insert and linear defects between the channel and external surface of the insert near the external surface at the approximate depth of 20–30 mm. The analysis of these defects is still in progress.

A BWR insert manufactured earlier in Finland was subjected to a series of fracture toughness tests. The fracture toughness values obtained from the tests were of a fairly good standard.

The inspections of the third VVER-type insert cast in 2011 (IPV3) were completed, and the fuel channels of the insert met the straightness requirements.

SEALING THE CANISTERDevelopment work on Posiva’s canister sealing process using the electron beam welding (EBW) method has continued. The sealing test performed in late 2011 with a full-side diameter canister hav-ing a short insert went without any problems. The results of this welding operation have been analysed, but the fi nal test results will only be available in early 2013.

New welds were produced in 2012 with the aim of investigating the repeat-ability, reliability and fl awlessness of the welding process. The results will be used, among other things, for choosing the canister sealing method and for as-sessing the performance of the welding process, i.e., in practice its reliability.

One signifi cant open question re-garding the long-term properties of the initial state of the weld is the residual stresses in the weld. The investigations regarding residual stresses continued

using fi nite element methods (FEM) of numerical computer modelling, destruc-tive tests and a particular measurement method termed a deep hole drilling method. The preliminary results indi-cate that the level of residual stresses is lower than that observed earlier, of the order of 40–50 MPa. The results will become more specifi c in 2013 when a summary report is produced of the re-sidual stresses.

Quality assurance of the welding process has been developed by charac-terising the beam of the EBW process and by further specifying the work in-structions. The shape and properties of the beam affect the fl awlessness of the weld. The current welding equipment has a measuring head for beam prop-erties, allowing, among other things, the power distribution of the weld to be measured using different welding parameters and in different conditions. With the help of this measuring head, the settings of the welding equipment can be verifi ed and the beam properties can be stored in electronic form.

Regarding friction stir welding (FSW), the information currently avail-able on the different parts of the welding process were compiled during autumn 2012 into a report which will be used in the comparison of welding processes to be done during 2013. Alternative weld-ing equipment solutions from different equipment manufacturers were investi-gated with the aim of fi nding equivalent sets of equipment in order to gain more operating experience of the commis-sioning and production use of FSW equipment. The work for planning the welding tests to be performed in spring 2013 using FSW equipment in the SKB canister laboratory in Oskarshamn and for defi ning the related requirements began in 2012.

CANISTER WELD INSPECTIONSThe co-operation on inspection activi-ties between SKB and Posiva continued in 2012. The cooperation concentrated on analysing the reliability of inspec-tions, on developing surface inspection methods and on component inspections. The reliability analysis of inspections concentrates on assessing the compo-

27

Figure 10. Classifi cation of lid materials on the ba-sis of the back wall echo.

nent inspection results, on producing the Probability of Detection (POD) graphs and on assessing the infl uence of hu-man factors.

Several EB welds of good quality were inspected in 2012. Furthermore, a signifi cant evaluation of EB welds was performed on the basis of NDT measure-ments of the welds. The reports will be fi nalised by early 2013. The results will also be used when the welding method is selected in 2013.

Eddy current inspections are devel-oped for the surface inspections of cast copper billets. The depths of the liquid penetration test indications detected in three billets were assessed using eddy current techniques. The indications de-tected in the billets were eliminated by grinding if they were deep so that they did not end up in the fi nished tubes.

In all, seven copper lids were in-spected (Figure 10). The inspections revealed that one lid showed clearly stronger attenuation than the others. This was probably due to the large grain size of the base material and its variations. This lid had been manufactured using a different process.

The canister design, manufacture of canister components, their inspec-tions, the canister sealing weld and its inspection, transfer of the canister into the repository and its installation in the deposition hole were all described in the Canister Production Line 2012 report (POSIVA 2012-16) which was published as a subject-specifi c report of the construction licence application.

The buffer

The earlier started buffer wetting study was continued in 2012, and it produced information on the early behaviour of

the buffer in various conditions. The investigations and laboratory tests of fi lling the gap between the buffer and the bedrock with bentonite pellets also continued. Bentonite pellets of differ-ent shapes, sizes and types were made for the tests.

The ⅓-scale buffer test installed in investigation niche 1 of ONKALO at the end of 2011 continued in 2011.

Installation of the buffer blocks in the deposition hole in keeping with its verticality tolerances requires the de-position hole to have an even bottom, impossible to achieve using the depo-sition hole boring rig. That is why the work was started for designing a sepa-rate levelling device for the deposition hole bottom. The work for designing the moisture protection of the buffer during installation continued, and the detailed design of moisture protection compo-nents (bottom plate and the protective lining attached to it) was completed as the result of this work.

The development work regarding buffer block manufacturing techniques was continued by planning the produc-tion of full-scale blocks scheduled to commence in 2013. Manufacturing tests have been conducted by producing a few buffer blocks of ¾-scale. At the same time, larger amounts of small test pieces have been produced at the labo-ratory scale, and they have been used for investigating the impact of various factors on the manufacturing process in closer detail.

The manufacture of pellets of differ-ent types has been tested in manufactur-ing tests conducted in the laboratory, and their suitability for fi lling up the gap between the buffer and the bedrock has been investigated. The investigated properties have been the feasibility of

installation and compacting, as well as the thermal conductivity, erosion sus-ceptibility and swelling properties of the pellets.

Development of the buffer instal-lation techniques has continued in the LUCOEX project under Euratom’s 7th framework programme in cooperation between Posiva, SKB, Andra (France) and Nagra (Switzerland), where Po-siva’s role is to develop the installation and quality control of buffer blocks and the management of problems possibly arising during the installation process. The design work of the installation trol-ley and block transfer device used for installing the buffer blocks was com-pleted, and manufacture of the installa-tion trolley began during the latter half of the year. At the same time, the imple-mentation of installation demonstrations scheduled for 2013 and the tools used for managing any installation problems have been planned.

Following the buffer design work undertaken during the last few years, a buffer production line report (POSIVA 201-17) was published at the end of 2012 as part of the construction licence application process.

Tunnel backfi lling

The development work for backfi lling of deposition tunnels concentrated in 2012 on updating the deposition tunnel backfi ll design. The backfi ll production line report (POSIVA 2012-18) was com-pleted. The end plug of the deposition tunnel is also included in the report. The production line report describes the production process of deposition tunnel backfi ll and end plug from the procure-ment of raw materials to the manufac-ture and installation of components

28

Figure 11. Overview of the production line for deposition tunnel backfi ll.

Figure 12. Prototype of the in-stallation device for deposition tunnel backfi ll material.

(Figure 11). The production line report presents the implementation of different phases of the production chain and the quality control measures deployed at each stage. In, addition, the production line report describes the requirements, initial state and conformity of the initial state of the deposition tunnel backfi ll and the end plug.

The planning of tests investigating the installation and behaviour of the deposition tunnel foundation layer be-gan in 2012. The purpose of the tests is to investigate the effectiveness of dif-ferent compacting techniques and their suitability for installing the foundation layer. The planning and testing of qual-ity control methods for the foundation layer is also a key element of the tests.

As part of the development work for the backfi ll design, the ability of the backfi ll pellets to store the seepage water entering the tunnel during the backfi ll process was investigated in cooperation with SKB. An attempt was made in the tests to distribute the seepage waters entering the tunnel in certain spots to a

wider area in the already installed pel-let front so that the ability of the pellet front to store seepage waters could be better utilised.

The industrial-scale manufacture of backfi ll blocks was tested by manufac-turing small series of blocks with a size of the same order as the fi nal blocks that will be used for backfi lling the deposi-tion tunnels. Samples were taken of the

blocks for analysing their density and moisture properties as well as the suit-ability of the method used. The results were used as the basis for designing a compression mould suitable for in-dustrial production and for preparing a package handling process using a robot, suitable for manufacturing the blocks. The feasibility of the manufacturing method has been tested in compression

29

tests and by numeric modelling of the compression process.

The design work for the tunnel back-fi ll installation device has begun. The concept chosen as the basis for design work is that of an electrically actuated device (Figure 12). The key elements of the device include a backfi ll block conveyor having robots equipped with suction grippers at both ends for ma-nipulating the blocks. Blowing with compressed air is the primary alternative considered for the pellet backfi ll pro-cess. The logistics of backfi ll materials in the immediate vicinity of the device will be analysed at the conceptual level.

A demonstration project (POPLU) was initiated in 2012 for the purpose of implementing a deposition tunnel end plug as a component-specifi c test in the demonstration area of ONKALO in 2014. Since 2010, Posiva has also par-

ticipated in a joint project with SKB for the purpose of constructing a full-scale plug test (DOMPLU) in the Äspö Hard Rock Laboratory in early 2013.

Both Posiva’s POPLU and SKB’s full-scale DOMPLU plug tests are in-cluded in the DOPAS project which was initiated in spring 2012 under Eura-tom’s 7th framework programme and is coordinated by Posiva. A total of 17 companies responsible for nuclear waste management and research institutes are participating in the project. The DOPAS project is primarily concentrating on the development and full-scale testing of plugs and closure structures for the disposal facilities of spent nuclear fuel. In addition to the POPLU project imple-mented in ONKALO, full-scale plugs are also implemented in France, the Czech Republic, Sweden and Germany in underground research facilities locat-

ed in different geological environments.

Closure of the facilities

Closure of the underground disposal facility is described in the closure pro-duction line report (POSIVA 2012-19), completed at the end of 2012. Regard-ing the closure of investigation holes, the dismantling of the plug in hole OL-KR24 by over coring and investigation of the bentonite located inside the per-forated copper tube has been planned. The dismantling project of the Prototype Repository, a full-scale disposal dem-onstration constructed in the Swedish Äspö Hard Rock Laboratory tunnel at the depth of 460 metres, has continued with analysis of the results. In addition to SKB and Posiva, six other national nuclear waste organisations are partici-

pating in the project.

30

Main items of the safety case and the production process

Plan for the production of evidence in support of the Safety Case

Posiva submitted the construction li-cence application for the encapsulation plant and disposal facility of spent nu-clear fuel in 2012. In the licence applica-tion, the long-term safety of disposal is discussed as the so-called Safety Case. According to an internationally adopted defi nition, “Safety Case” refers to all the technical-scientifi c documentation, analyses, observations, tests and other evidence that are used to substantiate the safety of disposal and the reliability of the assessments thereof. The main reports included in the Safety Case and their foreseen schedule up to 2012 are shown in the Safety Case Plan 2008 (Posiva 2008-05), and this plan has been further updated on the basis of STUK’s comments.

The following reports included in the Safety Case report portfolio were compiled in 2012:

• the Performance Assessment Re- port regarding demonstration of the performance of the disposal system (POSIVA 2012-04),• the Features, Events and Processes (FEP) report (POSIVA 2012-07), presenting a description of signifi cant features, events and processes and the interactions between them.• the Design Basis report (POSIVA 2012-03), presenting the design basis of the KBS-3V disposal solution from the perspective of long-term safety on the basis of Posiva’s requirements management system, • the Formulation of radionuclide release scenarios report (POSIVA 2012-08), presenting the systematically justifi ed selection of scenarios for the disposal site and the repository for the purpose of scenario analyses,• the Assessment of radionuclide re-

lease scenarios for the repository system, a report analysing the scenarios leading to releases of radionuclides (POSIVA 2012-09),• Description of Disposal System (POSIVA 2012-05), a report describing the disposal facility,• the Complementary Considerations report describing anthropogenic and natural analogies, calculations made using simplifi ed methods as well as the observations regarding the geological history of the disposal site and other possible analyses in support of the Safety Case (POSIVA 2012-11),• the Biosphere Description report (POSIVA 2012-06),• the Biosphere Assessment report presenting doses to people, animals and plants (POSIVA 2012-10), and• the Synthesis report presenting a summary of the design basis, meth- odology used for the Safety Case as well as the main results of the performance analysis and the safety analysis regarding the disposal facility to be built in Olkiluoto (POSIVA 2012- 12).

The reports will be published dur-ing 2013. In addition, preliminary plans were made in 2012 regarding the con-tents of the Models and Data and Bio-sphere Data Basis reports. The reports will describe all models and initial data used in the Safety Case. The reports will be published during 2013.

Performance of release barriers

EXTERNAL CONDITIONSIn 2009, Posiva started, in co-operation with SKB and NWMO of Canada, the four-year Greenland Analogy Project (GAP) with the main objective of estab-lishing the effects of the ice sheet on the circulation and chemical properties of groundwater. The results of this project

will be required for assessing the safety of disposal deploying the KBS-3 solu-tion in ice age conditions. The results of this project will also help analyse the degree of realism in the existing ice age models and modelling of groundwater chemistry during an ice age. The year 2012 was exceptional in the research area and the whole of Greenland, be-cause surface thawing was observed in international studies almost throughout the ice sheet. The automatic weather stations such as the one shown in Figure 13 are used for measuring various pa-rameters including the air temperature, amount of thermal radiation from the Sun and surface temperature of the ice sheet in the research area. In 2012, the main objective of the GAP was to es-tablish in greater detail the sub-glacial topography in the research area and to investigate the sub-glacial pressure con-ditions and the geochemistry of liquid water present at the bottom. Attempts were also made to take water samples from the 648-metre deep drillhole bored in front of the glaciers in 2011. However, the sampling was unsuccessful due to technical reasons, which is why a new attempt will be made in 2013. The 2012 fi eld work and results of the GAP will be reported by the end of 2013.

During 2011 and 2012, a reconstruc-tion has been made of the behaviour and paleo-environments of the Lake Dis-trict Ice Stream near the edge of the ice sheet during the last ice age in the Lake Saimaa and the Salpauselkä area. The main subject of the study was the Kylän-niemi area, part of the second Salpaus-selkä ridge, where the deglacialisation phases of the area were studied using geological and geophysical methods. The results of the 2011 studies have al-ready been reported, whereas the 2012 studies will be reported in early 2013.

In 2010–2012, Posiva has updated the climatic scenario for Olkiluoto in cooperation with the Finnish Meteoro-

31

Figure 13. Automatic weather station on the ice sheet in the research area of the Greenland Analogy Project. (photo: Dirk van As)

logical Institute. In 2012, the modelling descriptions were supplemented with a 10,000-year climatic simulation where the UW and UVIC models of the Max Planck Institute were used. These mod-els also allow taking into account the carbon cycle in the simulations, unlike the 100,000-year climatic modelling performed in 2011.The results indicate that the Earth’s climate will warm up by 0.3–8 degrees during the current millen-nium due to the greenhouse gas emis-sions produced by mankind. The amount of warming will depend on the amount of emissions. It would take over 10,000 years for the climate to be restored to its pre-industrial stage. The model simula-tions made using small, relatively large or large emissions predicted that the cli-mate in Olkiluoto would continue to be moderate during the next 10,000 years. There are major uncertainties associated with the future seawater levels. During the next few millennia, the average level

of water in the Baltic sea may rise by 0.3–8 m as a result of the thermal expan-sion of seas, the melting of glaciers on land areas and the changes taking place in the thermohaline circulation of the North Atlantic. The land uplift following the last ice age, in progress at the same time, is expected to be about 8 m dur-ing the next 1,500 years and about 36 m during the next 10,000 years.

The work for modelling perma-frost, biosphere, surface hydrology and groundwater fl ows inside bedrock, based on the climatic scenarios pro-duced in 2010–2012 and the descrip-tions contained in them regarding future warm and cold periods and rainfall was completed in 2012. In 2013, working reports in the English language will be published on the permafrost, surface hydrology and bedrock groundwater fl ow modelling work, while a POSIVA report will be published on biosphere modelling.

FUEL Posiva is participating in the REDUPP (Reducing Uncertainty in Performance Prediction) project included in the 7th framework programme of Euratom. The purpose of the project is to improve the understanding of how representative the results obtained in laboratory conditions are of the phenomena and processes tak-ing place in fi nal disposal conditions. The solubility of uranium oxide into natural waters was tested in 2012. The FIRST Nuclides project of Euratom’s 7th framework programme also began in 2012. Posiva’s part of the project involves investigating the solubility of fuel with a high discharge burn-up value.

THE CANISTERThe investigations spanning many years and related to the corrosion of copper in water continued in 2012. Tests will be conducted in cooperation with SKB, and their objective is to repeat the tests

32

published by Hultquist and Szakálos in 2008.

Modelling simulations were per-formed in 2012 using the data from the copper creep tests initiated in 2006 as input data. The purpose of the simula-tions was to estimate the service life of the copper canister. The results are presented in Posiva’s working report 2012-96. The development work regard-ing different corrosion models of copper also continued in 2012.

THE BUFFER, BACKFILLING AND CLOSURE OF THE REPOSITORYThe studies on buffer, backfi ll and clo-sure behaviour, and processes assumed to be detrimental, will produce estimates of the compliance of technical solu-tions with the requirements, as well as initial data for a safety assessment and development of design requirements. Performance studies regarding these engineered barriers were conducted in 2012. The studies focussed on the buffer and backfi lling of the deposition tunnels. During 2012, the development of min-eralogical and chemical characterisation of bentonite was continued as well as the development of empirical and numerical methods by also including backfi ll ma-terials in the studies. In addition to the above, the most signifi cant individual subjects of study have, like in the previ-ous years, been the following:

• Saturation with water in general,• Erosion of buffer and backfi ll materials possibly associated with the early stage of water saturation,• Erosion of buffer material in dilute waters,• Interaction between saturated bentonite and cement,• Mechanical interaction between the tunnel and backfi ll, and• Mineralogical alteration of the buffer material.

The performance assessment of the different parts of the engineered bar-rier system is presented in connection with the Performance Assessment re-port included in the Safety Case report portfolio.

During 2012, Posiva also partici-pated in international research projects on the behaviour of bentonite, such as

• The FORGE (Fate Of Reposi- tory GasEs) project of Euratom’s 7th framework programme, • The CFM (Colloid Formation and Migration) project of the Grimsel rock laboratory, • The FEBEXe (Collaboration in the Full Scale Engineered Barrier Ex- periment in Crystalline Host Rock) project, and • The BELBaR (Bentonite Erosion: effects on the Long term performance of the engineered Barrier and Radionuclide Transport) project of Euratom’s 7th framework programme.

The FORGE-related work continued to concentrate in 2012 on monitoring, as planned, the Large Scale Gas Injec-tion Test (LASGIT). Field tests were conducted in the CFM for assessing the formation and migration of colloids in dilute waters, while the development of methods for assessing these test results was continued. As in previous years, the FEBEXe project continued the monitor-ing of the long-term test and collection of data from it. The BELBaR project continued the earlier started small-scale tests and computer modelling for esti-mating the erosion of bentonite caused by dilute waters.

As in previous years, Posiva has par-ticipated in SKB-coordinated work in the EBS Task Force for the development of assessment procedures and model-ling tools regarding clay materials. The work for analysing the modelling cases of saturation of bentonite, agreed with the previous working group, was further continued in 2012.

In 2011, Posiva participated in the ABM (Alternative Buffer Materials) and in the LOT (Long term test of buf-fer material at the Äspö HRL) long-term projects where the processes taking place in different bentonite materials are investigated in a large-scale test.

Posiva has participated, in the ca-pacity of an expert, in an international natural analogue study, the purpose of which is to accumulate knowledge on the long-term stability of bentonite un-der high pH conditions. Investigations were conducted in 2012 for further specifying the results reported in 2011.

In 2012, Posiva continued its par-ticipation in the international Enhanced Sealing Project that will run for several years in Canada and is monitoring the performance of the plug used for sealing off the shaft. The other participants in the project are SKB of Sweden, Andra of France and NWMO of Canada. In addition, Posiva continued SKB’s joint project for further development of the plugging of deposition tunnels, initiated at the beginning of 2011.

BEDROCK AS A RELEASE BARRIERThe long-term safety studies continued with Nagra (Switzerland), JAEA (Japan) and NDA (Great Britain) in the LCS (Long-term Cement Studies) project aimed at studying the interactions of grouting cement with bedrock in situ in the Grimsel rock laboratory in Switzer-land. The purpose of the laboratory tests conducted in support of the fi eld tests is to model the dissolving of cement and its interactions with the bedrock. The re-sults of laboratory and fi eld tests are also modelled by utilising the information obtained from natural analogy studies. The fi rst phase of the project continued until the turn of the year 2008/2009, and the results have been reported in Nagra’s report series. The second phase of the LCS project has begun, and it is sched-uled to continue during 2009–2013.

The spent fuel safety assessment will include an estimate of the behav-iour of radionuclides in the geosphere. As part of this estimate, the migration of radionuclides as well as their reten-tion in the rock material and surfaces of bedrock fractures will be analysed. The magnitude of retention of dissolved ra-dionuclides is described by the distribu-tion factor. The value of the distribution factor depends on the conditions, which is why the values best describing the distribution in the analysed chemical and physical environments (types of rock and minerals present in Olkiluoto and the composition of its groundwater) are selected for the migration estimates. The empirical work for updating the values of these parameters for the most important radionuclides began in 2008, and it continued in keeping with the

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planned schedule in 2012. The work for reporting the results is still in progress.

The EU’s CROCK (Crystalline Rock Retention Processes) project investi-gates the uncertainties associated with sorption estimates and the methods for estimating the Kd values in bedrock groundwater conditions for which no direct empirical test results are avail-able. Posiva participates in the project as an end user and by fi nancing part of VTT’s work in work packets. The fi rst packet deals with molecular-level sorp-tion and surface complexation model-ling and the second with applying the modelling to the disposal system’s per-formance analyses. In 2012, the sorption of nickel into biotite, a mineral widely present in Olkiluoto, was investigated. Molecular-level modelling was used to describe the cation exchange of nickel

to the basal surfaces of biotite and its complex formation on the end surfaces. When the sorption model of reactive chemistry was fi rst adapted to the titra-tion results of reference biotite samples obtained from Luumäki, the preliminary results indicated that sorption to the bio-tite present in Olkiluoto is considerably stronger than what could be deducted from the specifi c area based on BET measurements.

Samples have been taken once a year from selected groundwater sta-tions in ONKALO for determining the concentration of colloids or humic acid and fulvic acid in groundwater. So far, the analysed concentrations have been low, but the monitoring will continue.

BIOSPHERE Biosphere-related work was carried

out in 2012 in line with the TKS-2009 programme and the revised Safety Case plan (POSIVA 2008-05), with the main focus on the modelling required for the biosphere assessment of the construc-tion licence phase and its background work that will mainly be reported in early 2013. In addition, the soil sorp-tion tests were continued. As in previous years, samples of water and shore veg-etation were collected from Olkiluoto and a few Satakunta lakes similar to the ones that will in the future be formed in the vicinity of Olkiluoto for use as input data of modelling of element pools and fl uxes in the environment. The com-bined mapping of peat layer and vegeta-tion initiated in 2010 in the Lastensuo swamp was supplemented. Posiva also actively participated in the activities of the international BIOPROTA forum.

34

Development of the horizontal disposal solution

In parallel with the vertical disposal design (KBS-3V) now constituting Po-siva’s reference solution, the develop-ment work for the horizontal disposal design (KBS-3H) has continued with SKB, concentrating on the specifi c char-acteristics of the horizontal design. A joint project entitled “KBS-3H System Design 2011–2016” was established in 2011 for further development work on the horizontal solution. Alongside the joint project, Posiva has also prepared in its plant design work for the space needs and requirements set by the 3H solution.

The main objective of the joint project is to develop the technical en-gineering of the 3H alternative and understanding of its systems to a level where a Preliminary Safety Assessment Report (PSAR) can be produced for the 3H alternative and used for a compari-son between the 3V and 3H alternatives. The comparison of the two alternatives also includes environmental issues, costs and safety issues (long-term, op-erational and occupational safety). The objective regarding long-term safety is to demonstrate that 3H is at least as safe an alternative as 3V.

A full-scale demonstration of the DAWE (Drainage and Artifi cial Water-ing and Air Evacuation) design solution chosen as the reference solution in 2010, entitled the Multipurpose Test (MPT), will be implemented in the Äspö Hard Rock Laboratory. The MPT is part of the four-year international LucoeX project, initiated in 2011 and scheduled to end at the end of 2014. The purpose of the MPT is to test the manufacture, transport and installation of main components, as well as the techniques compliant with the DAWE design solution, such as ar-tifi cial wetting of the clay material. In addition, the joint performance of the components and the behaviour of clay material will be tested; samples will be taken for the latter purpose at the end of the test. The installation work for

the MPT is scheduled to begin in April 2013, and the planned duration of the fi eld phase is 400 days.

The Multipurpose Test will be im-plemented in a horizontal 3H drift ex-cavated earlier in Äspö at level -220 m. The drift is 95 metres long and has an approximate diameter of 1.85 metres. A section of about 20 metres has been separated of this horizontal drift for the test. In 2012, the preparatory measures for the MPT demonstration have mainly been associated with

• preparations of the test area, including its characterisation,• manufacture of the components required for the test (compartment plug, supercontainer, distance blocks and fi lling components (transition block, pellet fi lling and bottom block)), • planning the instrumentation for components,• updating and testing the deposition equipment and software, and• laboratory tests and modelling work aimed at advance modelling of the MPT, such as those related to the extrusion of bentonite through the perforated protective cylinder.

The compartment plugs and backfi ll components will be made of MX80-type bentonite. In addition to the above com-ponents, bentonite is also contained in the supercontainer where it surrounds the canister. The compartment plug is a steel plug, similar to the one that pro-duced good results during the previous phase of the project. At this stage, there are no capabilities in place yet for test-ing a compartment or drift plug made of titanium in compliance with the DAWE design solution.

The deposition niche has been ex-cavated for the KBS-3H demonstration drift planned to be excavated later dur-ing this stage of the project in the Äspö HRL at level -420 m. Drilling/boring a straight pilot hole requires a suffi ciently

accurate set of tools for measuring the horizontal and vertical deviations. A test hole has been constructed at ground lev-el in the Äspö island, and its coordinates have been accurately measured. The test hole has initially been constructed at a length of 60 m, but the plan is to extend it to 300 m at a later stage. It is suitable for testing and calibrating the measuring tools discussed above.

The joint project has also included the detailed design work for the com-partment plugs, artifi cial wetting tubes and the air evacuation pipe, as well as in-vestigations regarding the specifi c char-acteristics related to welding titanium.

The following tests and modelling work aimed at the advance modelling of the Multipurpose Test have been performed:

• Small-scale laboratory test entitled ”Extrusion of bentonite through the holes in the perforated protective cylinder of the supercontainer and its modelling• Modelling of the Big Bertha test (no. 1) performed during an earlier phase of the project for investigating the extrusion of bentonite in a 3H deposition drift.

Preparations have been made for advance modelling of the MPT, but the eventual implementation/ordering of the work, as well as its scope, are linked, among other things, to the results of the above modelling reports and the assess-ment made on their basis of the prereq-uisites for the modelling work. Initiation of the Big Bertha test (no. 2) has been postponed until January 2013. This is an important test for the MPT, because both will investigate, among other things, the extrusion of bentonite through the holes in the perforated protective cylinder in different scales.

The production of two production line reports entitled ”Design, Construc-tion and Initial State of the KBS-3H Underground Openings” and ”Buffer

35

Figure 14. Conceptual illustration of the reloading station associated with the KBS-3H design. The supercontainer is assembled inside the transport shielding tube in vertical position. The supercontainer consists of a perforated protective cylinder (made of titanium) and the buffer bentonite and copper canister installed inside it. The fi gure shows the canister being inserted in the supercontainer. After that, the fi nal bentonite block and the top plate of the supercontainer are installed. Finally, the radiation protection gate of the transport shielding tube is installed. The transport shielding tube is lifted to a horizontal position on the transport support. The transport vehicle takes the transport shielding tube to the disposal area. (picture: Timo Kirkkomäki, Fortum Power and Heat Oy)

bentonite and fi lling components” began in 2012. In addition to these, other pro-duction line reports to be initiated later and describing the specifi c characteris-tics of the 3H design include ”Super-container” and ”Plugs”. In addition to the common part of the 3H design, the production line reports also describe any differences between Posiva and SKB.

Analyses regarding Forsmark site have been initiated in the SKB-Posiva joint project which are related to the can-ister failure modes of several canisters due to the erosion of bentonite caused by dilute glacial water after an ice age and followed by enhanced canister corro-

sion, as well as to canister failures due to shear movements in the bedrock. These are the key areas for investigation identi-fi ed in the preliminary KBS-3H safety analysis in 2008. The work concerning Forsmark will be completed in 2013, after which the corresponding analysis regarding Olkiluoto will be initiated. The work will be performed regarding the chosen DAWE reference solution.

A study on the long-term interaction between buffer bentonite and titanium, the material selected for the protective cylinder, was initiated. It is scheduled to end in 2014. The work is based on earlier research regarding the interaction

between titanium and bentonite. The study focuses on chemical processes which may have a deteriorating effect on the safety performance of the buffer.

A report was produced in 2011 of the layout and stepwise implementation of the KBS-3H concept in the Olkiluoto bedrock. The next update is due in 2013. The design work for the 3H solution has continued in Posiva’s plant design func-tion. Figure 14 is a conceptual descrip-tion, developed in the plant design func-tion, of a facility to be constructed in connection with the reloading station of the 3H design where the supercontainer is assembled ready for fi nal disposal.

36

Licencing and other activities

Construction licence application

The target of Posiva and its owners, TVO and Fortum, is to start the fi nal disposal of spent nuclear fuel in Olki-luoto, Eurajoki, in around 2020. This schedule is supported by the wide consensus of society, also recorded in the decision taken by the Ministry of Trade and Industry in 2003 regarding the time schedules for preparing the fi nal disposal of spent nuclear fuel. The decision of the Ministry of Trade and Industry also required Posiva to submit the licence application regarding the construction of the encapsulation plant and the disposal facility to the ministry by the end of 2012.

The licence application regarding the construction of the encapsulation plant and the disposal facility in Olki-luoto was submitted, with appendices documentation, to the Ministry of Em-ployment and the Economy at the end of 2012. The application consisted of documents prescribed in sections 31 and 32 of the Nuclear Energy Decree (161/1988) regarding, among other things, the company, the disposal site, the plant complex to be built, the plan-ning and safety principles and safety signifi cance. In addition, the reports required in earlier decisions-in-principle regarding transports, retrievability and environmental impacts were also at-tached to the application. The principal conclusion in the application documen-tation is that the encapsulation plant and disposal facility can be constructed in Olkiluoto so that the fi nal disposal of spent nuclear fuel could commence around 2020.

The application documentation submitted to the ministry consisted of nearly fi ve hundred pages in all. The application was drew up in the Finnish language, and its key parts will also be translated into Swedish. The application

is available via Posiva’s website. In connection with submitting the

application, the Radiation and Nuclear Safety Authority (STUK) was provided with the reports prescribed in section 35 of the Nuclear Energy Decree, Gov-ernment Decree 736/2008 and STUK’s Regulatory Guides on nuclear safety (YVL Guides). The application docu-mentation sent to STUK consisted of a total of several hundred separate docu-ments and numerous background reports referred to in the above documents. The application documentation sent to STUK will be supplemented during the fi rst half of 2013 with certain reports, particularly related to demonstrating the long-term safety. In addition, the preliminary reports will be further de-fi ned according to the Nuclear Energy Decree as Posiva’s design work will progress and inspections by STUK has been performed, both before and after the construction licence will be issued. The fi nal documentation on fi nal dis-posal with their justifi cations related to the demonstration of long-term safety will be submitted in connection with the operating licence application in com-pliance with section 36 of the Nuclear Energy Decree.

The main conclusion of the reports submitted to STUK in connection with the construction licence application is that the fi nal disposal of spent nuclear fuel can be safely executed in the man-ner described in the documentation, both from the perspectives of operational safety and long-term safety.

Other licences, permits and decisions required

Land use planningThe primary objective of land use plan-ning is to maintain the land use prerequi-sites at the largest energy production site in Finland and to reserve space for the implementation of fi nal disposal of spent

nuclear fuel so that the requirements set by Finnish legislation and operational safety are fulfi lled. The Olkiluoto par-tial master plan that became legally valid in 2010 and the local plan of the disposal area that became legally valid in 2011 meet Posiva’s needs for the next few decades. Future expansion of the repository to cater for the disposal requirements of new plant units in an ap-propriate manner regarding the bedrock conditions may need the current land use plans to be changed. The suffi ciency and development needs of land use planning were also discussed in the documents appended to the construction licence application submitted to the Ministry of Employment and the Economy.

Environmental impact assessmentPosiva carried out an Environmental Impact Assessment (EIA) procedure regarding the expansion of its reposi-tory last time during 2008–2009. In the statement issued in 1999 by the Ministry of Trade and Industry was stated that the construction licence application must be accompanied by an EIA report and an account of the design principles that the applicant intends to observe in order to avoid environmental damage and to reduce the environmental load. This requirement was taken into account in the construction licence application by updating the EIA report of 2009 to correspond to the latest knowledge of the disposal concept, plant site and surrounding environment as well as the results of safety analyses. The main conclusion of the assessment reports is that the fi nal disposal of spent nuclear fuel in Olkiluoto can be executed in a manner acceptable from the perspective of environmental impact.

Environmental permitIn 2011, Posiva received from the Re-gional State Administration Agency (AVI) for Southern Finland the request-

37

ed report regarding the necessity of ob-taining an environmental permit for the construction or operation of the disposal facility. The report of the AVI says, with the grounds stated, that the construction and operation of the disposal facility do not require any permits referred to in the Environmental Protection Act or the Water Act other than the current envi-ronmental permit related to the deposi-tion of rock material. Nevertheless, the report states that pursuant to section 84 of the Environmental Protection Act, the competent authority in matters related to environmental permits is the Centre for Economic Development, Transport and the Environment, which is why the AVI also sent its report for information to the Centre for Economic Development, Transport and the Environment for Southwest Finland. The interpretation of the Centre for Economic Development, Transport and the Environment regard-ing the necessity of the environmental permit was re-checked in 2012 with the Centre for Economic Development, Transport and the Environment (AVI) for Southwest Finland.

Quality and environment management

Quality management and the operations management systemPosiva’s operations management system consists of manuals providing an over-view of Posiva’s operations, as well as of supplementary process descriptions, codes of practice and instructions. The purpose of the operations management system is to ensure that Posiva’s dis-posal facility meets the relevant safety requirements and that Posiva’s opera-tions are safe, timely and cost effective.

The comprehensiveness and func-tionality of the operations management system was assessed twice in 2012 in management reviews, and the processes of the operations management system were subjected to ten internal audits.

In October, DNV Certifi cation Oy carried out a periodic audit of the oc-cupational health and safety system in compliance with the ISO 9001 quality certifi cate and the OHSAS 18001 stan-dard as well as a re-certifi cation audit of

the ISO 14001 environmental certifi cate.Supplier audits were carried out for

major suppliers; the purpose of these audits is to verify the ability of these suppliers to provide Posiva with services compliant with the requirements.

STUK carried out inspections ac-cording to its plan regarding the con-struction of ONKALO. Regular STUK follow-up meetings were held between STUK and Posiva, and separate site in-spections were performed. The STUK-approved schedule for submitting ONK-ALO design documents and the plan for giving information on construction details were observed in the ONKALO construction project.

Control of environmental impactThe company manages environmental matters in line with the certifi ed opera-tions management system and the annu-al action plan. As part of its construction licence application, Posiva produced an up-to-date report of the environmental impact of its operations. The report in-dicates that the company’s operations do not produce a major environmental impact. The major environmental as-pects in normal operations are related to ONKALO’s construction, waste handling and the use of energy. In case of disturbance in operation, chemical spills is the most signifi cant environ-mental risk.

In 2012, the excavation work in ONKALO produced some 14,000 m3 of rock waste, part of which was used for building works in the area and for tunnel maintenance. A total of some 10,000 m3 of water was used in the tunnel construction work. The average rate of water seepage in ONKALO was approximately 37 l/min. The waters pumped from the tunnel (operational water and seepage waters) were fi rst led to sedimentation and oil separation and then to the sea via an open ditch. As in previous years, the quality of water was regularly monitored.

The action plan describes the mea-sures aimed at reducing any environ-mental hazards caused by the company’s operations. Waste management was de-veloped in 2012, among other things, by closer cooperation with TVO.

Occupational safety

The principles and practical procedures observed in occupational safety man-agement at Posiva are described in its operations management system. The occupational safety risks associated with working underground are in many ways more diffi cult to manage than those as-sociated with work above ground. For example, the occurrences of rocks and boulders falling off the bedrock face after excavation work as a result of relaxing bedrock stresses can only be completely controlled by reinforcing the entire excavated bedrock face. In prin-ciple, such a procedure confl icts with both Posiva’s own research and with offi cial inspections. Following the fatal accident in 2011, the conditions of rock construction work were changed so that working in non-reinforced facilities was virtually banned. In 2012, there were no accidents in ONKALO resulting in a sick leave.

The only signifi cant occurrence from the occupational safety point of view in 2012 was the failure of the clutch of the pressure suction vehicle on 24.5.2012 at ONKALO chainage 3700 (at the ap-proximate depth of 370 metres) and the resulting oil fi re with its associated ex-tensive smoke formation. The driver and co-driver of the vehicle extinguished the fi re, raised the necessary alarms and ini-tiated other actions for limiting the dam-age. A total of 20 persons were working at the end of the tunnel during the inci-dent. They stayed below the location of the fi re for almost four hours, the time it took to ventilate the smoke away. Provisions have been made for such situations by placing safety containers in ONKALO. It would also have been possible to transport the personnel back to ground level using a maintenance and safety cage. The incident did not put the workers at risk, but it showed how seri-ous the risks posed by tunnel fi res are. Following the incident, Posiva ordered an external expert assessment of its fi re safety capabilities, and the assessment was done during the latter half of 2012. The assessment identifi ed several areas for development, and a development plan was drawn up for these.

38

No accidents resulting in sick leave occurred in the construction activities above ground in 2012. This can be assessed to be due to both a smaller amount of work done and the fact that more attention was paid to occupational safety matters following the negative trend observed in 2011.

Information management

Knowledge managementPosiva and its interest groups intend to ensure that basic knowledge is preserved at least over the coming decades and the coming century as employees and generations change.

The threat is the discontinuation of disposal activities if doubts are raised for whatever reason that the long-term safety has fl aws, and the bases of the analyses are no longer recalled and understood.

For the purpose of developing knowledge management, a KMS project was initiated in 2011. Its purpose was to design and implement a search portal for both internal use and external use that will be restricted using existing identifi -cation tool technology. Another purpose was to organise the information content of the reports produced in the research activities to better facilitate searches and to scan and OCR the published reports only available in printed form and then store them in the document management system. In the course of the project, about 2,300 reports from the archives were converted into electronic form. About 3,400 reports published by Posiva and its predecessors during 1979–2012 can now be found with the new search portal. The search portal will also be made available for external organiza-tions during 2013.

Requirements managementThe VAHA requirements management project was established in 2006 for the purpose of planning and implementing a systematic procedure for managing the requirements concerning the dis-posal project.

The goal of the project was to create a data system for collecting all require-ments concerning disposal and their grounds, details of solutions for meeting the requirements, as well as informa-tion on the linkages between different requirements.

The first version of the require-ments database for disposal operations was introduced in the autumn of 2007, and the contents were revised during 2008–2010.

STUK and some other external or-ganisations have remote access to the approved requirement management information.

Documentation managementA project for developing the documenta-tion management was initiated at Posiva in late 2011. Its main purpose was to produce a report of the current state of documentation management and an in-formation management plan to be used as the basis of ensuring that Posiva’s operational documentation is compre-hensive and can be found throughout the entire life span of the information concerned. As a result of the project, an information management plan was created for Posiva, and a document management development team was established to coordinate the planned further actions.

Research data systemsPosiva has a large amount of research data, collected over a few decades in

Olkiluoto and other localities where Posiva has previously conducted studies and surveys. The extensive data mate-rial contains research data of various subjects including the characteristics of bedrock in the area, the behaviour and chemistry of bedrock groundwaters and of environmental studies.

The work on specifying the POTTI system began in 2004 with the speci-fi cation of data to be stored, intended uses of the database, the operating en-vironment and the extent of database usage. Among others things, the POTTI system has interfaces with the REPRO, POSE and BENTO studies in progress in ONKALO, as well as with the auto-matic groundwater measuring system in ONKALO, the HYPERDATA borehole data system and the Surpac bedrock modelling system. Following the im-provements made in the system during 2012, the system now provides steady operation and reliable data searches. The documentation and database descrip-tions of the system were also updated to refl ect the current status. Research data is being recorded in the normal manner.

Posiva’s HYPERDATA system is intended for viewing and visualising Olkiluoto borehole data, and it utilises the research data stored in the POTTI research data system. The images of bore core box contents from Olkiluoto and ONKALO boreholes as well as the images of borehole walls and acoustic images were processed and stored in the POTTI system during 2008–2012. Seismogram and radargram modules were added to the system in 2012. The system also has available tunnel images from ONKALO.

39

Operating waste management

The Olkiluoto repository for operating waste (VLJ reposi-tory) was commissioned in 1992. The repository consists of two rock silos, a hall connecting the two and auxiliary facilities constructed at a depth of 60–100 metres inside the bedrock in the Ulkopää peninsula of Olkiluoto Island. The facilities can be accessed both via the vehicle access tunnel and a shaft. Low-level waste is deposited in the rock silo inside a concrete box, while a silo of steel-reinforced concrete has been constructed for intermediate-level waste in the other rock silo. The silo for low-level waste has a capacity of about 5,000 m3, while the capacity of the intermediate-level waste silo is about 3,500 m3(these volumes apply to waste placed in 200-litre drums). An application process is currently pending where an amend-ment is being sought to the terms and conditions of the current operating licence of the VLJ repository that would allow the disposal of operating waste from OL3 in the VLJ repository.

A preliminary design for the extension of the VLJ reposi-tory has been prepared, aimed at the new repository facili-ties that will be required around the 2030s. The extension will correspond to the increase in the operating life of OL1 and OL2 from the initial 40 years to the current 60 years, and allows for the implementation of the disposal plan for operating and decommissioning waste from the OL3 plant unit now under construction. The needs of the planned new power plant unit (OL4) will also be taken into account when planning the expansion of the repository.

Low-level and intermediate-level operating waste gener-ated at the Loviisa power plant is fi nally disposed of in facilities built in the bedrock of Hästholmen Island. The Loviisa disposal facility consists of a 1,170-metre-long access tunnel and hall facilities built at a depth of about 110 metres and of personnel and ventilation shafts. The facility was built in a number of stages.

Construction work on the repository began in 1993, and its fi rst phase was completed at the end of 1996. The re-pository received its operating licence in 1998 and was put to disposal use in 1999. The fi rst construction stage

involved the excavation of most facilities and access routes. Two deposition tunnels were excavated for maintenance waste, and a repository hall was excavated for solidifi ed waste. The second deposition tunnel and solidifi ed waste hall were completed during the second construction phase that ended in 2007. The construction work for maintenance waste repository facility 3 (HJT3) and the connecting tun-nel began in October 2010. The expansion will improve the facilities for interim storage and sorting of maintenance waste drums. HJT3 will be commissioned for the interim storage of waste drums during 2013.

The Olkiluoto power plant

PRINCIPLE OF OPERATIONSThe majority of operating waste is immediately packed for processing, storage and disposal. The intermediate-level ion exchange resins used for the

purification of circulating water are solidifi ed in bitumen, and the composi-tion is poured into steel drums. A part of the low-level waste (compressible miscellaneous maintenance waste) is compacted in steel drums using a hy-draulic press, while another part (scrap

metal and fi lter rods) is packed, without compaction, in steel and concrete cases and steel drums. The drums containing compressible waste are compressed so that the fi nal height of the drum is ap-proximately one-half of the original, with the diameter of the drum remain-

40

Plants (m3)

VLJ-repository (m3)

Other storage facil it ies (m3)

OL1 OL2 KAJ-Silo MAJ- Others KAJ MAJ Silo

LOW-LEVEL

WASTE

Scrap 0.2 2,784.9 10.6 2,796

Unpacked scrap 51.8 1) 52

Maintenance waste 11.6 6.9 960.1 3.2 2) 18.0 14.9 1,015

Miscellaneous liquids 5.0 5.6 0.6 11

Solifi ed liquids 1.0 0.2 96.8 98

Waste oil 10.8 11

INTERMEDIATE-

LEVEL WASTE

Scrap 26.5 26.3 267.9 321

Resin powders 51.0 62.0 1,263.8 1,377

Resin granules 11.2 8.6 265.6 285

TOTAL 106 110 1,797 3,842 3.2 80 15 11 5,965

Total (m3)

Table 1. Quantities of low-and intermediate-level waste at the Olkiluoto power plant by type of waste in the storage fa-cilities and repositories of the plant site (MAJ and KAJ storage silos) on 31.12.2012.

1) Includes 10.8 m3 (2 pcs) of 342-type heat exchang-ers sent to Studsvik; these are included in the KAJ storage fi gure until the lots are returned2) Tank used for the gas generation test, located in the excavation tunnel of the VLJ repository

ing unchanged. Scrap metal may also be processed before packing to reduce its volume. Scrap chopped up with a metal chopper may be used to fi ll up any empty space in the concrete cases transported to the repository. This improves the packing effi ciency of metal waste.

Miscellaneous liquid waste and slur-ry is solidifi ed by mixing the waste with a binding agent in a drum that forms the packaging of the solidifi ed product. If applicable, the volume of liquids and slurries is reduced through evaporation prior to solidifi cation.

Operating waste is temporarily stored in the storages and fuel pools of the power plant units, the low- and inter-mediate-level waste interim storage fa-cilities (the KAJ and MAJ storages) and, in small quantities, in the KPA storage at the Olkiluoto power plant site. Low and intermediate-level waste generated during the operation of the power plant is disposed of in the current waste silos of the repository for operating waste (the VLJ repository). Waste with very low activity concentration is exempted from control and taken to the landfi ll

area located at the Olkiluoto power plant site or handed over to another party for recycling or other purposes.

Low-level operating waste can also be processed in external processing plants. The reheaters of OL1 and OL2 plant units replaced in 2005 and 2006 were sent in 2010 to Studsvik, Sweden for chopping up and melting. They were returned from there in 2011 and 2012. In the second lot, decommissioned parts from low- and high-pressure turbine and heat exchangers were sent to Studsvik in 2012. Thanks to processing, the waste, its mass and volume now considerably reduced, will be disposed of in the MAJ silo of the VLJ repository in Olkiluoto.

CURRENT STATUS OF STORAGE AND DISPOSALThe status of storage and disposal at the end of 2012 is shown in Table 1. The waste is packed in barrels (200 litres in each, about 100 litres when compacted), to steel crates (1.3 or 1.4 m3 in each) and in concrete crates (5.2 m3 or 3.9 m3 net in each).

The barrels and crates are stored,

when required, in storage facilities of plant units and the KAJ storage before their fi nal disposal in the VLJ repository. Before transferring them to the VLJ re-pository, the barrels and steel crates are placed in large and small concrete crates as follows: 16 barrels, or a combination of seven barrels and two steel crates, are placed in each large concrete crate and 12 barrels are placed in each small concrete crate. The number of barrels accommodated by each concrete box can be doubled by compacting the bar-rels. Dismantling waste from the reactor interior, such as core lattices and steam separators, is included in the waste packed in crates of 1.8 m3 for long-term storage in the fuel pools of plant units.

Large contaminated metal compo-nents are stored in the KAJ storage and in the MAJ storage extension. In addi-tion, unpacked operating waste such as used ventilation fi lters and resins without bitumen, are stored at the plant units, while waste oil is stored at the in-terim spent fuel storage (KPA Storage). Part of the unpacked waste is to be later released from control for recycling use

Spent fuel

interimstorage

41

or dumping on landfi ll sites. The waste buildings at the plant units can accom-modate about 1,000 barrels each. Mostly only very low-level maintenance bags and scrap to be released from control is kept at the MAJ Storage. The KAJ Stor-age can accommodate barrels, crates and large contaminated metal components corresponding to a total volume of some 6,000 barrels.

The capacity of the intermediate-level waste silo in the VLJ repository (expressed in 200-litre barrels) is 17,360 barrels while that of the low-level waste silo is 24,800 barrels of operating waste. This corresponds to the quantity of waste generated by the two plant units now in operation in Olkiluoto during 40–60 years (Figure 15).

The small waste items held by STUK are stored, by separate agreement, in the Olkiluoto VLJ repository. These small waste items mainly consist of radioac-tive elements used in hospitals, research institutes and industrial plants. So far, about 57 m3 of small waste items have been accumulated in the VLJ reposi-

tory. Following the change in operating licence conditions in 2012, this waste can also be fi nally disposed of in the VLJ repository.

Expressed in terms of disposal vol-ume, the fi lters of OL1 and OL2 plant units and waste containers in the waste building have a total volume of 34 m3 (computational fi gure) of resin powders and granules.

IN-SERVICE STUDIES REGARD-ING THE VLJ REPOSITORYThe safety of nuclear waste disposal includes the safety of the repository during its operation and the long-term safety of disposal. For the bedrock, the monitoring of safety during operation involves the monitoring of its stability. Long-term safety is assessed through safety analyses that require a knowledge of the geology, hydro-geochemistry and groundwater chemistry of the bedrock surrounding the repository. The primary purpose of bedrock studies and moni-toring during the operating phase is to investigate how the excavation work

has affected the properties of bedrock in the area and how these properties change during the operating phase. The studies and monitoring measurements also produce valuable information for the future expansion of the VLJ reposi-tory (Figure 15).

The rock-mechanical and hydro-logical monitoring of the VLJ reposi-tory is carried out in accordance with the respective bedrock investigation and monitoring programme drawn up for 2006–2017. The programme should be revised in 2015 to correspond to any changes in the requirements for research results and in order to continue the pro-gramme. The results of rock-mechanical and hydrological monitoring are re-ported annually in the following spring at the latest in separate reports as part of TVO’s series of VLJ reports.

In-service monitoring of the VLJ repository rock facilities continued in 2012 in accordance with the VLJ reposi-tory bedrock research and monitoring programme. 2012 was a normal moni-toring year according to the research and

Figure 15. The Olkiluoto VLJ repository in its ex-tended state, seen from south-west. The two silos seen in the background (KAJ and MAJ-käyttö1) belong to the part of the VLJ repository in use. The expansion plan also has space reserved for the operating waste of the OL3 and OL4 plant units and decommissioning waste of all four plant units.

42

monitoring programme. The results for 2012 will be published in spring 2013. The previous results for 2011 were reported in spring 2012 (VLJ-2/12, VLJ-3/12).

Rock-mechanical monitoringThe stability of bedrock has been moni-tored from the early stages of excavation work for the VLJ repository with con-tinuous rock dislocation and rock bolt loading measurements as well as with measurements of changes in the span dimensions of excavated facilities utilis-ing convergence measurement bolts. The measurement results for 2011 were reported in spring 2012 (VLJ-2/12).

In rock mechanics, a normal mea-surement programme was implemented in 2012 when convergence measure-ments were excluded from the pro-gramme. Convergence measurements were last carried out in 2010, and they are next scheduled for 2015. The rock-mechanical monitoring measurements carried out in 2012 did not indicate any changes in the rock mechanics of the VLJ repository. The mechanical condi-tion of the rock was still good, and no surprises were encountered regarding the behaviour of the bedrock. The small changes at the measuring points were due to changes in rock temperature. However, the rock temperatures dur-ing the transition behaviour of the rock have stabilised as predicted. Overall, the rock-mechanical measuring instru-ments operated well in 2012. Minor cases of spurious readings have still been observed in certain measurement instruments from time to time. There was no need to replace extensometer heads during 2012.

In spring 1993, ten test bolts were in-stalled in the research tunnel of the Olki-luoto VLJ repository for the purpose of determining the rate of corrosion in rock bolts. The purpose of the study is to pro-duce information on the corrosion resis-tance of zinc-plated rock reinforcement bolts in the conditions prevailing at the Olkiluoto VLJ repository assuming that the cement plaster protecting the bolts has totally lost its protective properties. The fi rst test bolt was bored out in 1996 and the next one in 2004. The results for

the latter bolt were reported in 2006. The results indicate that the rate of corrosion is negligible, which is why the decision was taken to further postpone the next removal boring until 2014.

Hydrological monitoringThe seepage water flow in the VLJ Repository was monitored in 2012 by measuring the discharge pump flow rates. The weir measurements were not included in the 2012 programme. The hydraulic height of groundwater was observed at the automatic measure-ment points. The amount of rainfall was measured at the Ulkopää peninsula, and sea level data were obtained from the Rauma harbour observatory of the Me-teorological Institute of Finland.

The measurement results for 2011 were reported in spring 2012 (VLJ-3/12). In 2012, the average seepage water fl ow in the VLJ Repository was 40.0 litres/min, which is of the same order as in the previous years. The long-term trend of the total fl ow of seepage water still indicates a declining trend, albeit that the total fl ow would seem to have become more constant during the last few years.

The leaking points of the VLJ Re-pository are photographed every fi ve years in accordance with the research and monitoring programme and reported together with hydrological monitoring results. The latest reported set of pho-tographs dates back to November 2010.

Groundwater chemistryNo water samples were taken in 2012 from the groundwater stations in the VLJ repository. The previous exten-sive sampling campaign took place in spring 2011. During the years of more extensive sampling, the samples taken from three groundwater stations are analysed for the chemistry but also for isotope compositions. In addition to the water samples, gas samples are also taken from each groundwater station for analysis of dissolved gases and isotope compositions. The next round of sam-pling from the groundwater stations as part of the larger programme will take place in February 2015.

The changes in analysis results dur-

ing the period 2008–2011 have been small and all water samples have been neutral. Although the latest analysis re-sults for 2011 lead to the conclusion that a more stable phase has been reached in the groundwater conditions of the VLJ Repository bedrock, the groundwater chemistry cannot be assumed to be stable yet. The groundwater chemistry cannot be assumed to be totally stable yet, as some changes have taken place in individual parameters. The long-term analysis results of groundwater chemis-try were compiled in 2012, and they will be published in the VLJ series in 2013.

Air quality in the VLJ repositoryThe air quality in the VLJ Repository is monitored by radon concentration measurements at various measurement points and by exhaust air radioactivity measurements. Radon measurements have been done from the VLJ Reposi-tory air since 1991, and the original measurement method was replaced in 2009 by radon detection containers supplied by STUK. The radon concen-tration measurement points are in the same locations as in previous years. In 2012, the measurement period was two months. The changed method and length of the measurement period have not had any signifi cant effect on the results. The measurement results for 2011 are pre-sented in a report (VLJ-3/12).

The radon concentration in places of regular work must not exceed the limit value prescribed in the Radiation Decree (400 Bq/m3). In 2012, a concen-tration value exceeding this limit value was measured in the VLJ repository in three measurement points: in the storage facilities for STUK’s small waste items (900 Bq/m3), in a measurement point located near the MAJ silo (470 Bq/m3) and in a measurement point located at the bottom of a test well (1,640 Bq/m3). The limit value has also been exceeded in these measurement points in previous years. In 2012, the radon concentrations in all measurement points were of the same order of magnitude as in 2011.

The quality of exhaust air from the VLJ Repository has been monitored since 1999. The presence of any radio-active substances in the exhaust air has

43

been investigated by aerosol sampling. The exhaust air was analysed twice during 2012. As in previous years, no radioactive substances were observed in the exhaust air. The temperature, relative humidity and carbon dioxide concentration of repository air was also monitored. The average temperature and relative humidity in the reposi-tory were in 2012 close to the average values for the entire monitored period (1991–2012). The CO

2 concentrations

of the excavation tunnel were slightly elevated in late 2012 as work was in progress in the tunnel at that time.

Research related to operating and decommis-sioning waste

Gas generation testMicrobiological decay of low-level maintenance waste in repository condi-tions is being studied in a large-scale gas generation test performed with test equipment erected in the VLJ repository excavation tunnel (Figure 16). The study has continued since 1997. The study

serves to specify further the estimate on the amount and generation rate of gas generated from maintenance waste and to improve knowledge of the impact of microbial activity on the whole decay process. The corrosion of steel under conditions which are similar to those after the VLJ repository has also been sealed off. The factors important for the processes in the test are the simulation of conditions and variation of materials in the 20 m3 test tank between waste barrel contents, each barrel with a spe-cifi c content, and the volume of water between them. Due to the heterogeneous conditions, microbes are more likely to have favourable microenvironments, which has already been confi rmed by the test results. In addition to chemical monitoring, the release of activity from the waste barrels into the surrounding water is also monitored.

The objective of the study is to pro-duce an estimate of the gas generation rate for the safety analysis of the VLJ repository that was last updated in 2006. Over a longer period, the gas genera-tion rate has stabilised to 60–90 dm3/

month, which is almost one order of magnitude smaller than the value taken for the initial safety analysis of the VLJ repository. The gas being released is mainly methane generated by the reac-tion of hydrogen and carbon dioxide that already takes place inside the tank. Dur-ing the test, the pH of the water between the waste barrels has decreased from alkaline (> 10) to neutral. The decrease is thought to be caused by microbial metabolism, and it is larger than the ex-pectations of the alkalinity of concrete. The strong corrosion observed in the steel sheet samples from barrels and the high concentration of sulphate-reducing substances analysed in the microbiologi-cal samples also agree with the change in pH values. The conductivity and redox potential of water have steadily increased over the ten-year period, to ap-proximately 1,500 mS/m and -300 mV (Eh), respectively.

An interim assessment of the test results was reported in 2012 for the purpose of establishing the changes in test tank conditions as well as any future development or actions required

Figure 16. Gas generation test equipment in the VLJ repository of Olkiluoto.

44

Figure 17. Investigation niche for investigating the long-term durability of concrete in the VLJ repository

(VLJ-1/12). Water samples were taken from the tank in 2012 for microbiologi-cal analysis. The analysis results were presented in a working report which was used as the basis for planning a more extensive sampling campaign in 2013. A Master’s Thesis work has been initi-ated in 2012 regarding assessment of the status of the gas generation test and the criteria for ending the test.

The gas generation test is permitted to continue until 2017. One of the objec-tives of the Master’s Thesis work is to

create the criteria for ending the test. In addition, an extensive microbiological sampling campaign, including both wa-ter and material samples, will be imple-mented during 2013. The information and analysis reports obtained from these will produce additional information on the state and functioning of the test. Information on the development of pH values during the test can probably also be utilised in the future when the assess-ment of long-term safety of the disposal of operating waste is revised. The plan

regarding the termination of the test is scheduled for completion in 2014. The test modelling work was temporarily discontinued in 2012, but the report of results for 2006–2011 provides a good justifi cation for that.

Long-term dura bility of concreteThe long-term behaviour of concrete structures is investigated in a project initiated in 1997 in cooperation with Fortum. Up to December 2010, the pilot-scale simulated test was in progress in Myyrmäki, in the facilities of former IVO. After the intended use of the fa-cilities changed, the decision was taken to move the test to the research facility of the VLJ repository in Olkiluoto at a level of -60 m. (Figure 17), and the tests were re-started in early 2011.

The results of the study are used for estimating the impact of the long-term behaviour of concrete on the solubility and migration of radionuclides under repository conditions as well as the weathering of concrete under ground-water conditions corresponding to actual

Figure 18. Concrete test pieces in steel sample baskets , taken from actual groundwater condi-tions for sampling.

45

operating conditions. The purpose of the study is to identify concrete formula-tions that are the most durable under the prevailing conditions so that the require-ment of 60 years’ service life set for the VLJ repository can be achieved, and to produce information for the modelling of long-term durability of concrete ma-terials and for developing these models. Another objective is to obtain informa-tion for the modelling of long-term durability of concrete materials and for developing the models.

As part of the project regarding the long-term durability of concrete, an extensive set of concrete samples was made available to a project in the KYT2014 programme in 2011 for more extensive research and modelling and for increasing international cooperation on a subject that can be utilised more widely than just for the VLJ repository. In addition to the pilot test in progress in the investigation niche of the VLJ repository, similar concrete test pieces are being studied under actual ground-water conditions in the Olkiluoto VLJ Repository in boreholes VLJ-KR20 and VLJ-KR21. The test pieces are shown in Figure 18.

This study involves monitoring the behaviour of nine concrete formula-tions with different binding materials and aggregate-to-binding material ratios in nine different solutions simulating groundwater conditions. In addition to determining the chemical composition profi le of concrete, its mineral composi-tion and hydratation will also be anal-ysed. In addition, tests for investigating the microstructure and porosity will be made using optical microscopy and electron microscopy and by establish-ing the capillary suction capacity of the concrete samples.

No samples were taken of the test pieces in the boreholes in 2012, but the water chemistry of boreholes (pH, oxygen content, redox potential and conductivity) was monitored, besides monthly manual pH and conductivity measurements, also by the annual cell array measurement campaign lasting one month. Water samples were also taken for chemical analyses. The pH of water samples taken from boreholes has

remained very constant, at about 8, over a long period.

The research results related to the damage mechanisms of concrete struc-tures will be reported later for different concrete grades in 2011–2014; the fi rst reports were published during 2012. The primary damage mechanisms of concrete structures under the prevailing conditions have been identifi ed. During the operating phase, the properties of concrete will deteriorate as a result of carbonate formation, and the aggres-sive ions contained in groundwater will cause corrosion in the concrete reinforcement steel after the closure of the facility. The penetration of salts into concrete depends of the type of concrete and on the composition and concentration of the saline water. The model to be developed for predicting the penetration requires the detailed determination of penetration profi les of different salt components and simul-taneous mineralogical investigation. A simplifi ed analysis of results was carried out in 2011 on the basis of the measured chloride profi les. The chloride curves were modelled, and the models were used as the basis for determining the diffusion constant of concrete for chlo-rides. The modelling curves can be used for roughly estimating the penetration depth of chlorides as a function of time.

Dissolution of decommissioning waste metalsThe purpose of the decommissioning waste metal dissolution test initiated in 1998 is to study the dissolving of car-bon steel under repository conditions in order to obtain a realistic picture of the corrosion rate of steel under the condi-tions prevailing in the Olkiluoto VLJ repository after its closure. The tests are implemented both under simulated conditions in a laboratory (VTT’s moni-toring study) and in actual groundwater conditions at the Olkiluoto VLJ reposi-tory using carbon steel samples placed in boreholes VLJ-KR19 and VLJ-KR21. Furthermore, samples of zinc plates and zinc-coated steel plates have been in-stalled in borehole VLJ-KR9 since 2002.

Groundwater chemistry in the bore-holes is regularly monitored with pH,

oxygen, redox potential and conduc-tivity measurements. Water samples are also taken every year for chemical analyses. The conductivity of borehole KR19 varies in the range of 2.3–4.4 mS/cm and that of borehole KR9 in the range of 2.4–3.0 mS/cm. Samples were also taken in 2010 of borehole water and test pieces for microbiological analy-ses. Samples were also removed from boreholes for weight loss tests in order to determine the rate of corrosion. The results were reported in January 2011. The corrosion rates calculated on the basis of weight loss measurements of carbon steel samples have been found to vary between boreholes, which is partly due to the differences in total test durations. The corrosion rate also varies from sample to sample, and local corro-sion can considerably exceed the aver-age rate. The research results indicate that both the local water chemistry and microbiological activity in boreholes af-fect the corrosion rate and consequently also the predictability of corrosion and therefore also the estimates on corro-sion rates.

The dissolution of decommissioning waste metals project was on hold during 2012, and no new samples were taken from the boreholes in the VLJ reposi-tory. In the sampling campaign of 2010, microbiological samples were taken from the surface of carbon steel and zinc samples for preliminary microbiologi-cal analyses. Some of the samples were also deep-frozen for DNA analyses. The analysis of these DNA samples was completed in spring 2012, and the used molecular biology methods showed that a very diverse microbial population was present on the surfaces of all analysed carbon steel samples. Deltaproteo bac-teria were dominant in all samples, and they were by far the most signifi cant individual class of bacteria. Most of the sulphate-reducing bacteria, for example, are Deltaproteo species. In addition to the sulphate-reducing bacteria, strains of the Clostridia and Anaerolineae classes were also detected. The observed diver-sity of the bacteria population would seem to indicate that the bacteria found on the surfaces of carbon steel samples also have potential for extensive func-

46

Ta ble 2. Operating waste generated by the Loviisa power plant

Total amont of waste

Used ion exchange resins 534 15,000

Evaporation residues 756 1,170

Solidifi ed evaporation residues 31.1 7

and ion exchange resins

Solvents solidifi ed by absorption, - 65.2 < 1

low-level ion exchange resins and

active carbon

Maintenance waste 382.2 1,771.6 641.6

Activity

At the plant/in storage bui ldings

(m3)

At the repository

(m3) (GBq)

tional diversity. In addition to the reduc-tion of sulphates, microbial species were also detected that are capable of reduc-ing iron or nitrate, as well as species that are capable of oxidising methane. The solubility test results of decommission-ing waste metals obtained in 2011 were made available to the KYT2014 pro-gramme. In the research programme, the test material has been supplemented by tests on stainless steel samples in tests using actual groundwater taken from the VLJ Repository as the test environment.

The Loviisa power plant

PRINCIPLE OF OPERATIONSLow-level and intermediate-level reac-tor waste generated at the Loviisa NPP is processed and stored at the plant. The

used ion exchange resins and evaporator concentrates are stored in tanks in the liquid waste storage. Trial runs of the liquid waste solidifi cation plant based on cementation have been carried out since 2007, and the plant is to be com-missioned in 2013.

In the early 1990s, a method was introduced in Loviisa for separating ra-dioactive caesium from evaporator con-centrate into a very small waste volume. The removal of caesium reduces the activity of the evaporator concentrate to such a low level that it can be discarded using normal drainage procedures. By the end of 2009, a total of more than 1,460 m3 of evaporator concentrate had been purifi ed at the caesium separation plant using 34 ion exchange columns, each with a volume of eight litres. The

most recent purifi cation campaign initi-ated in 2010 was suspended in 2011 due to problems with pumps. The plan is to complete the campaign in 2013.

The dry maintenance waste gener-ated in power plant maintenance and repair work is packed into 200-litre steel drums. Compressible waste is pressed into the drums using a baling press; in this way, one drum may be made to hold fi ve times more waste than without compression. In 2012, a total of 151 m3 of maintenance waste was released from control.

Metal waste generated in the con-trolled area (Figure 19) is released from control in campaigns, as the situation requires, and collected into suitable waste batches. About 98.7 tonnes of metal scrap found clean in the radia-tion measurements were released from control in 2012.

Interim storage of radioactive metal waste takes place in the storage facili-ties of the controlled area. The storage hall for maintenance waste drums to be released from control also holds one ocean-freight container full of contami-nated metal waste.

Trial operation runs of the solidifi ca-tion plant (cementing plant) for liquid/wet active operating waste have been performed using evaporator concentrate since 2007. Trial operation runs on used ion exchange resins began in 2009, and the process of obtaining an operation licence for production use is scheduled to take place in 2013.

The situation regarding storage and fi nal disposal at the end of 2012 is shown

Figure 19. Metal waste processing facilities, semi-automatic saw. (Photo: Ari Haimi)

47

in Table 2. The used ion exchange resins and evaporator concentrates are stored in the liquid waste storage. In addition, 1.7 m3 of resins is kept in solidifi ed form in barrel-shaped waste containers. The waste solidifi ed by absorption is kept in 200-litre drums.

REPOSITORY Low-level and intermediate-level waste generated in the operation of the Loviisa power plant is fi nally disposed of in facilities built in the power plant area bedrock. The disposal facility consists of a 1,170 metre long access tunnel, tun-nel and hall facilities built at a depth of about 110 metres, and of personnel and ventilation shafts.

The construction work for mainte-nance waste facility 3 (HJT3) and the connection tunnel began in 2010; the excavation work (about 16,000 m3) was completed in 2011. The expansion will improve the facilities for interim stor-age and sorting of maintenance waste drums. HJT3 will be commissioned for the interim storage of waste drums dur-ing 2013. Separate research programmes have been compiled for in-service re-search of the VLJ repository concern-ing the access tunnel and hall facilities.

STUDIES ON SOLIDIFICATION METHODS Storage testing of radioactive ion ex-change resin solidified in half-scale disposal containers in 1987 continued in 2012. The waste packages have been stored in groundwater at the Loviisa power plant for 25 years and, as ex-pected, they are still in good condition. No structural damage has been detected in the concrete surface of the containers, and the composition of the storage water has been relatively stable. Radioactivity monitoring of the storage water has not revealed any signs of nuclide release from the solidifi ed product contained in the concrete containers. The test results

were last reported in 2010. In 1980, old inactive ion exchange

resin from the Loviisa power plant was solidifi ed in a full-scale disposal con-tainer. The disposal container was kept in storage until mid-1983, after which it has been kept in slowly fl owing fresh

Figure 20. The new maintenance waste facility, HJT3, was completed at the Loviisa NPP for long-term interim storage of waste in 2011. (Photo: Ari Haimi)

water at the Pyhäkoski power plant. The condition of the disposal container has been monitored after 1, 3, 5, 9, 13, 15, 21 and 27 years of storage. Rusting can be clearly seen on the steel lifting lugs and fastenings but no structural damage has been detected on the container’s concrete surface, and no corrosion has been detected in the concrete reinforce-ments of the container. The test results were last reported in 2010 together with the test results for half-scale disposal vessels.

IN-SERVICE STUDIES REGARD-ING THE REPOSITORY The in-service studies on the repository continued in 2012 in line with the moni-toring programme. The aim of the pro-gramme is to investigate and monitor the characteristics and behaviour of ground-water and the bedrock in the immediate surroundings of the disposal facilities as well as long-term changes in their behaviour. The monitoring programme has included the monthly monitoring of groundwater levels in ground-level research holes. The position of fresh and so-called saline groundwater in the holes was measured on four occasions during the year.

The electrical conductivity and pres-sure of groundwater as well as the seep-age water volumes have been measured at the repository facilities once a month.

Some pressure and seepage water mea-surements have also run continuously. The measurements concentrated on the seepage water pools and on the fi ve purpose-built groundwater stations. The research programme on ground-water chemistry included sampling and analysis of samples from groundwater station LPVA3.

The monitoring of slow bedrock movements has been performed mainly using an automated rock-mechanical measuring system. Visual inspections of the facilities also continued in 2012. The groundwater in the island of Hästholmen is characterised by the fact that its level clearly depends on the seawater level. This is most evident in deep (> 30 m) boreholes where the groundwater level is close to the seawater level. In shallow holes, the level is a few metres higher, depending on the topography. During the construction works, the groundwa-ter level sank locally by a few metres in the areas surrounding the facilities, but the slow rising of the levels has been observed since the facilities were completed. As a whole, no signifi cant changes have taken place in water levels that seem to have stabilised roughly at the 1996 level. The borderline between fresh and saline groundwater has re-mained between levels -30 m and -80 m as in previous years, i.e. clearly above the repository facilities that are located

48

roughly at level -110 m. More extensive construction-induced changes at the in-terface were only observed in one bore-hole during 2011. In 2012, all interfaces remained at the previous year’s level.

The amount of seepage water was measured, as usual, at seven different points around the disposal facilities. After excavation work was completed in 1996, the total seepage was about 300 l/min at its highest, from which it has fairly constantly fallen to about 60 l/min in late 2012. About half of the seepage water amount comes from the access tunnel and the other half from other facilities. The electrical conductivity measured in conjunction with seepage water measurements varies from one part of the facilities to another, as in previous years, in the approximate range of 400–1,300 mS/m. These values repre-sent both the intermediate zone and the saline zone. The electrical conductivity increases with increasing depth (and sa-linity) and reaches its maximum value at station LPVA5 (level -110 m). The con-ductivity of seepage water pumped into the sea (a mixture of all seepage waters) has been about 930 mS/m on average.

The analysis results of samples taken from groundwater station LPVA3 have not signifi cantly changed from previous years. The pH at the groundwater station has varied slightly during the history of measurements, but has remained between 7.3 and 7.7 in recent years. In 2012, the electrical conductivity and TDS values of groundwater were 1,100 mS/m and 6,200 mg/l. The groundwater at LPVA3 is of the Na-CaCl type, and its TDS classifi cation is that of brack-ish water.

The bedrock temperature near the fa-cilities at a depth of 110 m is about 9–13

degrees. The results of rock-mechanical measurements show that the stability of the facilities has remained good and that, for example, the construction of the disposal facility for solidifi ed waste has not diminished the stability of rock in the immediate surroundings either. Dur-ing the construction work in 2005–2006 and 2010–2011, more variations were observed in bedrock movements, mainly as a result of the higher temperature in the hall, but now the movements have returned to their pre-construction level. The temperature has been on the rise in several measurement points during 2011–2012. However, this has not had any signifi cant effect on the movements.

Excavation of the HJT3 and the new connecting tunnel began in autumn 2010. Generally speaking, extensometer measurements indicate that the disloca-tions taking place at the ceilings and walls of rock facilities have been of the same order as in previous years, below 0.1 mm. The results of convergence measurements carried out in 2012 were generally at the same level as when the measurements were fi rst started. How-ever, the excavation work for the HJT3 and the connecting tunnel carried out in autumn 2010 was clearly evident in the measurement sections near the ex-cavation work. The situation seems to have settled down during 2011–2012. Usually the measurement intervals de-crease in these sections. At the end of the year, the decrease compared to the reference level was 1.15–2.00 mm. The measurement intervals near the HJT3 had grown by less than 1 mm. Elonga-tion of the measurement intervals was mainly observed in the sections of the new connecting tunnel immediately af-ter excavation work. At the end of 2012,

the change compared to the reference level was less than 2 mm.

Visual inspection of the facilities indicates that their overall stability is good. The concealed drains operate as planned, albeit the precipitation of iron contained in the groundwater requires that they are periodically cleaned in the vehicle access tunnel. Saline seep-age water causes localized corrosion of metal structures and also gives rise to occasional maintenance and repairs.

SAFETY REPORTS REGARDING THE DISPOSAL OF OPERATING WASTE The work of updating the Safety Case for the repository began in spring 2004 and was completed in spring 2006. The safety case deals with phenomena, events and processes which affect long-term safety, such as groundwater fl ows, the release of radionuclides from waste, their travel in the bedrock and biosphere, and many other specifi c issues. Accord-ing to the safety analysis, the radiation doses emanating from disposal are be-low dose limits, and the doses coming via waterways (lake, sea) are only a fraction of natural background radiation doses. Similarly, the deposited waste causes only a limited increase in total activity concentrations of radioactive elements in the environment. Accord-ing to the Safety Case, it is not even possible to identify any fairly probable chains of events which could deteriorate the long-term safety of disposal to an inadequate level.

During the year being reported, in-ternational developments regarding the Safety Case for operating waste disposal were monitored through conference vis-its and trade publications.

49

Decommissioning planning

The Olkiluoto power plant

The decommissioning studies are aimed at the technical and economic develop-ment of the dismantling plan and at specifying the initial data for the safety analysis. The decommissioning plan of Olkiluoto NPP was last updated in 2008. The update also included an update of the long-term safety analysis of the dis-posal of decommissioning waste. Most of the plan only applies to the plant units currently in operation, but the decom-missioning waste from four plant units were taken into account in the long term safety analysis. Furthermore, in 2008 a preliminary plan was completed for an extension to the disposal facilities for reactor and decommissioning waste; here, too, the waste from the two new plant units was taken into account in ad-dition to the units currently in operation. The next decommissioning plan for the Olkiluoto NPP will be presented in 2014 at the latest. That plan will include a compilation report of the results of new investigations presented below and their possible impacts on the cost estimate of decommissioning.

A report was produced during 2009 regarding the decommissioning costs of the OL3 plant unit. The results will be presented in the decommissioning plan that will accompany the application for the OL3 operating licence, and they will

According to the Nuclear Energy Act, the NPP licence holder is also re-sponsible for decommissioning the plant. In order to fulfi ll this obligation, the party responsible for waste management must produce a plan on the decommissioning methods and schedule as well as on the storage and fi nal disposal of decommissioning waste. The power companies have presented their updated decommissioning plans at fi ve-year intervals until 2008 when the statutory requirement for the frequency of submitting updated decom-missioning plans was changed to every six years. The most recent updated plan was completed late in 2008 for the Olkiluoto nuclear facility. The decommissioning plan for the Loviisa power plant was updated in 2012.

be taken into account when determin-ing the nuclear waste management fund contributions. The fi rst decommissioning plan for the Olkiluoto 3 plant unit will be presented as a separate document.

A report was produced in 2010 for the purpose of further specifying the decommissioning costs of the plant units currently in operation. It analysed the decommissioning costs in a case where the plant units are decommissioned be-fore the service life of 60 years foreseen for the OL1 and OL2 plant units had expired. The results were used in esti-mating the nuclear waste management fund contributions for 2011 and 2012. A revised estimate was produced during 2010 regarding the cost of demolishing the non-active plant parts and buildings. The result will not affect the fund contri-butions, but the information is required for IFRS-compliant accounting.

The report regarding re-assessment of the extent of dismantling and demol-ishing work involved in decommission-ing the plants currently in operation was completed during 2012 (VLJ-4/12). The starting point of this work was the fact that the offi cial instructions now have more stringent activity limits for release from control. According to the report, the amount of low-level waste may increase, but the disposal capacity planned for decommissioning waste will suffi ce. There will also be cost implica-

tions, but the provision for extending the scope of dismantling included in the current decommissioning cost estimate will be suffi cient to cover the estimated costs. As a disposal alternative for very low-level waste, a separate report made a preliminary assessment of the possibil-ity of fi nal disposal into soil (VLJ-6/12) instead of disposing of such waste in the VLJ repository. It was found that fi nal disposal into soil would be feasible both technically and with regard to its cost implications. In addition, a report re-garding the decommissioning of TVO’s interim storage for spent fuel (KPA-5/12) was also completed in 2012. The report updated the quantity and activity values of the dismantling waste coming from the interim storage for spent fuel.

The Loviisa power plant

Part of the low-level and intermediate-level nuclear waste generated during the operation of the Loviisa power plant will only be deposited in connection with decommissioning. This waste includes, for example, used protective elements, absorbers, neutron fl ux detectors, con-nector rods of control rods and fi ssion chambers. At the end of 2012, there were 218 used protective elements, 220 absorbers, 282 neutron fl ux detec-tors, 142 connector rods and 28 fi ssion chambers at the Loviisa power plant. Of these, the protective elements are in the spent fuel storage pools of the plant. The absorbers and fi ssion chambers are kept in purpose-built channels at spent fuel store 1. The neutron fl ux sensors and connector rods are stored in similar channels in the reactor hall.

The most recent update for the decommissioning plan for the Loviisa power plant (TJATE-G12-45) was completed at the end of 2012. The fol-lowing matters were investigated during 2009–2012 for the update: adherence to the ALARA principle during de-

50

commissioning work, licencing of the decommissioning operation, impact of decontamination of the primary circuit on the doses accumulated in the work, risk management in decommissioning work and the corrosion behaviour of steel and weathering of concrete under fi nal disposal conditions. The decom-missioning project of VVER reactors in Greiswald, Germany was also studied

in 2012.The decommissioning plan for the

Loviisa NPPs is based on the idea of dis-mantling immediately after 50 years’ of operation those radioactive parts which are not necessary for continuing the nuclear functions remaining at Hästhol-men (spent fuel storing, liquid waste solidifi cation and disposal of low- and intermediate-level waste). A decision on

decommissioning or continued opera-tion will only be made towards the end of the planned operating life. Similarly, the decision on whether the plant will be dismantled immediately or according to a delayed schedule will be made to-wards the end of operation before start-ing decommissioning. The next update of the decommissioning plan is due by the end of 2018.

51

The funds required for nuclear waste management are collected in the gov-ernmental nuclear waste management fund. The target for accumulating funds is determined on the basis of the total liabilities of nuclear waste manage-ment, confi rmed separately each year. The total liabilities of nuclear waste management include the future costs of all operations required for managing the

Provisions for the cost of nuclear waste management

quantity of nuclear waste accumulated by the end of the respective year.

TVO’s funding target for nuclear waste management in 2012 was EUR 1,179.1 million, while that of Fortum was EUR 940.6 million.

The Ministry of Employment and the Economy confi rmed EUR 1,242.3 million as TVO’s total liabilities for nu-clear waste management in 2012. TVO’s

funding target for 2013 was equal to the previous year’s liabilities, EUR 1,242.3 million. The Ministry of Employment and the Economy confi rmed EUR 996.2 million as Fortum’s total liabilities for nuclear waste management at the end of 2012. Fortum’s funding target for 2013 was also equal to the previous year’s liabilities, EUR 996.2 million.

52

List of reports

POSIVA 2012-01 Monitoring at Olkiluoto – a Programme for the Period before Repository Operation Posiva Oy ISBN 978-951-652-182-7

POSIVA 2012-02 Microstructure, Porosity and Mineralogy around Fractures in Olkiluoto Bedrock Jukka Kuva (ed.), Markko Myllys, Jussi Timonen, University of Jyväskylä Maarit Kelokaski, Marja Siitari-Kauppi, Jussi Ikonen, University of Helsinki Antero Lindberg, Geological Survey of Finland Ismo Aaltonen, Posiva Oy ISBN 978-951-652-183-4

POSIVA 2012-03 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Design Basis 2012 ISBN 978-951-652-184-1

POSIVA 2012-04 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Performance Assessment 2012 ISBN 978-951-652-185-8

POSIVA 2012-05 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Description of the Disposal System 2012 ISBN 978-951-652-186-5

POSIVA 2012-06 Olkiluoto Biosphere Description 2012 ISBN 978-951-652-187-2

POSIVA 2012-07 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Features, Events and Processes 2012 ISBN 978-951-652-188-9

POSIVA 2012-08 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Formulation of Radionuclide Release Scenarios 2012 ISBN 978-951-652-189-6

POSIVA 2012-09 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Assessment of Radionuclide Release Scenarios for the Repository System 2012 ISBN 978-951-652-190-2

POSIVA 2012-10 Safety case for the Spent Nuclear Fuel Disposal at Olkiluoto - Biosphere Assessment BSA-2012 ISBN 978-951-652-191-9 (in preparation)

POSIVA 2012-11 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Complementary Considerations 2012 Posiva Oy ISBN 978-951-652-192-6

POSIVA 2012-12 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Synthesis 2012 ISBN 978-951-652-193-3

POSIVA 2012-13 Canister Design 2012 Heikki Raiko, VTT ISBN 978-951-652-194-0

POSIVA 2012-14 Buffer Design 2012 Markku Juvankoski ISBN 978-951-652-195-7 (in preparation)

53

POSIVA 2012-15 Backfi ll Design 2012 ISBN 978-951-652-196-4

POSIVA 2012-16 Canister Production Line 2012 – Design, Production and Initial State of the Canister Heikki Raiko (ed.), VTT Barbara Pastina, Saanio & Riekkola Oy Tiina Jalonen, Leena Nolvi, Jorma Pitkänen & Timo Salonen, Posiva Oy ISBN 978-951-652-197-1

POSIVA 2012-17 Buffer Production Line 2012 – Design, Production, and Initial State of the Buffer Markku Juvankoski, Kari Ikonen, VTT Tiina Jalonen, Posiva Oy ISBN 978-951-652-198-8

POSIVA 2012-18 Backfi ll Production Line 2012 - Design, Production and Initial State of the Deposition Tunnel Backfi ll and Plug ISBN 978-951-652-199-5

POSIVA 2012-19 Closure Production Line 2012 - Design, Production and Initial State of Underground Disposal Facility Closure ISBN 978-951-652-200-8

POSIVA 2012-20 Representing Solute Transport through the Multi-Barrier Disposal System by Simplifi ed Concepts Antti Poteri, Henrik Nordman, Veli-Matti Pulkkanen, VTT Aimo Hautojärvi, Posiva Oy Pekka Kekäläinen, University of Jyväskylä, Deparment of Physics ISBN 978-951-652-201-5

POSIVA 2012-21 Layout Determining Features, their Infl uence Zones and Respect Distances at the Olkiluoto Site Tuomas Pere (ed.), Susanna Aro, Jussi Mattila, Posiva Oy Henry Ahokas, Tiina Vaittinen, Pöyry Finland Oy Liisa Wikström, Svensk Kärnbränslehantering AB ISBN 978-951-652-202-2

POSIVA 2012-22 Underground Openings Production Line 2012- Design, Production and Initial State of the Underground Openings ISBN 978-951-652-203-9 (in preparation)

POSIVA 2012-23 Site Engineering Report ISBN 978-951-652-204-6 (in preparation)

POSIVA 2012-24 Rock Suitability Classifi cation, RSC-2012 ISBN 978-951-652-205-3

POSIVA 2012-25 2D and 3D Finite Element Analysis of Buffer-Backfi ll Interaction Martino Leoni, Wesi Geotecnica Srl ISBN 978-951-652-206-0 (in preparation)

POSIVA 2012-26 Climate and Sea Level Scenarios for Olkiluoto for the Next 10,000 Years Natalia Pimenoff, Ari Venäläinen, Heikki Järvinen, Ilmatieteen laitos ISBN 978-951-652-207-7

POSIVA 2012-27 Geological Discrete Fracture Network Model for the Olkiluoto Site, Eurajoki, Finland: version 2.0 Aaron Fox, Kim Forchhammer, Anders Pettersson, Golder Associates AB Paul La Pointe, Doo-Hyun Lim, Golder Associates Inc. ISBN 978-951-652-208-4

POSIVA 2012-28 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Data Basis for the Biosphere Assessment BSA-2012 ISBN 978-951-652-209-1 (in preparation)

54

POSIVA 2012-29 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Terrain and Ecosystems Development Modelling in the Biosphere Assessment BSA-2012 ISBN 978-951-652-210-7 (in preparation

POSIVA 2012-30 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Surface and Near-surface Hydrological Modelling in the Biosphere Assessment BSA-2012 ISBN 978-951-652-211-4 (in preparation)

POSIVA 2012-31 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Radionuclide Transport and Dose Assessment for Humans in the Biosphere Assessment BSA-2012 ISBN 978-951-652-212-1 (in preparation)

POSIVA 2012-32 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto - Dose Assessment for the Plants and Animals in the Biosphere Assessment BSA-2012 ISBN 978-951-652-213-8 (in preparation)

POSIVA 2012-33 Underground Openings Line Demonstrations Stage 1, 2012 ISBN 978-951-652-214-5 (in preparation)

POSIVA 2012-34 Seismic Activity Parameters of the Olkiluoto Site Jouni Saari, ÅF-Consult Oy ISBN 978-951-652-215-2

POSIVA 2012-35 Inspection of Disposal Canisters Components Jorma Pitkänen, Posiva Oy ISBN 978-951-652-216-9 (in preparation)

POSIVA 2012-36 Analyses of Disposal Canister Falling Accidents Juha Kuutti, Ilkka Hakola, Stephania Fortino, VTT ISBN 978-951-652-217-6

POSIVA 2012-37 Long-Term Safety of the Maintenance and Decommissioning Waste of the Encapsulation Plant Olli Nummi, Jarkko Kyllönen, Tapani Eurajoki, Fortum Power and Heat ISBN 978-951-652-224-4

POSIVA 2012-38 Human Factors in NDT of the EB-Weld ISBN 978-951-652-225-1 (in preparation)

POSIVA 2012-39 Safety case for the disposal of spent nuclear fuel at Olkiluoto: Radionuclide solubility limits and migration parameters for the canister and the buffer Wersin, P., Kiczka, M., Rosch, D. ISBN 978-951-652-219-0 (in preparation)

POSIVA 2012-40 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto: Radio nuclide Solubility Limits and Migration Parameters for the Backfi ll Wersin, P., Kiczka, M., Rosch, D., Ochs, M., Trudel, D. ISBN 978-951-652-220-6 (in preparation)

POSIVA 2012-41 Safety Case for the Disposal of Spent Nuclear Fuel at Olkiluoto: Radionuclide Migration Parameters for the Geosphere Martti Hakanen, Heini Ervanne, Esa Puukko ISBN 978-951-652-221-3 (in preparation)

POSIVA 2012-42 Microbiology of Olkiluoto and ONKALO Groundwater 2012, Summary Report Karsten Pedersen, Malin Bomberg, Merja Itävaara ISBN 978-951-652-222-0 (in preparation)

POSIVA 2012-43 In Situ Stress Measurement with LVDT-cell – Method Description and Verifi cation Hakala, M., Siren, T., Kemppainen, K., Christiansson, R., Martin, D. ISBN 978-951-652-223-7 (in preparation)

55

POSIVA 2012-44 Clay erosion in dilute waters Schatz, T., Olin, M., Seppälä, A., Kanerva, N., Sane, P., Koskinen, K. ISBN 978-951-652-226-8 (in preparation)

POSIVA 2012-45 Current status of mechanical erosion studies of bentonite buffer Sane, P., Laurila, T., Olin, M., Koskinen, K. ISBN 978-951-652-227-5 (in preparation)

POSIVA 2012-46 2D and 3D fi nite element analysis of buffer-backfi ll interaction Leoni, M. ISBN 978-951-652-228-2 (in preparation)

POSIVA 2012-47 Thermo-Hydro-Mechanical Modelling of Buffer, Synthesis Report Olivella, S., Toprak, E., Mokni, E., Pintado, X. ISBN 978-951-652-229-9 (in preparation)

POSIVA 2012-48 Thermo-Hydraulic Modelling of Buffer and Backfi ll Pintado, X., Rautioaho, E. ISBN 978-951-652-230-5 (in preparation)

POSIVA 2012-49 Thermo-Hydro-Mechanical Tests of Buffer Material Pintado, X., Hassan, Md. M., Martikainen, J. ISBN 978-951-652-231-2 (in preparation)

POSIVA 2012-50 Description of KBS-3H Design Variant Antti Öhberg et al., Saanio & Riekkola Oy ISBN 978-951-652-232-9 (in preparation)

TJATE-G12-145 Decommissioning of the Loviisa Nuclear Power Plant. Edition 2012 Matti Kaisanlahti, Tapani Eurajoki, Elias Mayer, Tommi Rämä, Olli Nummi, Fortum Power and heat Ltd. December 2012

VLJ-1/12 Large scale gas generation experiment, reporting period 2006–2011 (in Finnish) Nykyri, M., Safram Oy TVO Working report February 2012

VLJ-2/12 Rock mechanics monitoring in the Olkiluoto VLJ repository for operating waste in 2011 (in Finnish) Johansson, E., Saanio & Riekkola Oy TVO Working report March 2012

VLJ-3/12 Hydrological monitoring in the Olkiluoto VLJ repository for operational waste in 2011 (in Finnish) Lehtonen, A., Saanio & Riekkola Oy TVO Working report April 2012

VLJ-4/12 Assessment of the extent of Olkiluoto 1 and 2 decommissioning (in Finnish) Kaisanlahti, M., Fortum Power and Heat Oy TVO Working report October 2012

VLJ-6/12 Near-surface disposal in Olkiluoto (in Finnish) Saanio, A., Kaisanlahti, M., Fortum Power and Heat Oy TVO Working report October 2012

KPA-5/12 Decommissioning plan of TVO´s interim storage of spent nuclear fuel (in Finnish) Kaisanlahti, M., Fortum Power and Heat Oy TVO Working report October 2012

56

Teollisuuden Voima OyjOlkiluoto

27160 EURAJOKItel. +358 (0)2 83 811

Fortum Power and Heat OyPL 100

00048 FORTUMtel. +358 (0)10 4511

Posiva Oy, Olkiluoto, 27160 Eurajokitel. +358 (0)2 83 7231, fax +358 (0)2 8372 3809

www.posiva.fi

Documents

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