NUCLEAR WASTE MANAGEMENT OF THE OLKILUOTO AND … · 2 | NUCLEAR WASTE MANAGEMENT OF THE OLKILUOTO AND LOVIISA POWER PLANTS I Summary 2018 This report is the report referred to in

NUCLEAR WASTE MANAGEMENT OF THE OLKILUOTO AND LOVIISA POWER PLANTS

Summary 2018

2 | NUCLEAR WASTE MANAGEMENT OF THE OLKILUOTO AND LOVIISA POWER PLANTS I Summary 2018

This report is the report referred to in the Nuclear Energy Decree presenting the activities that Teollisuuden Voima Oyj (TVO) and Fortum Power and Heat Oy (Fortum) as parties with the nuclear waste management obligation have carried out with respect to nuclear waste management in 2018.

The final disposal of operating waste has been imple-mented at Olkiluoto, Eurajoki and Hästholmen, Loviisa since the 1990s. The measures taken by the organisations responsible for nuclear waste focus on the management of operating waste, preparation for the final disposal of spent nuclear fuel at Olkiluoto and the operations of Posiva Oy (Posiva), which they jointly own. Nuclear waste manage-ment programme YJH-2015 published in the autumn of 2015 described the current state of research, development and planning work related to the final disposal of nuclear waste and the decommissioning of the power plants, as well as plans for 2016–2018 and preliminary plans for 2019–2021. As a rule, preparations for final disposal pro-gressed in 2018 according to the YJH-2015 programme. In the autumn of 2018, the YJH-2018 programme which

describes the plans for the years 2019–2021 and the pre-liminary plans for the years 2022–2024 was submitted to the Ministry of Employment and the Economy.

The events that took place in 2018 in relation to the nu-clear waste management efforts of TVO and Fortum are described briefly in the following paragraphs.

Nuclear waste management and decommissioning at Olkiluoto power plant

During the operating year, master planning for nuclear waste management of low- and intermediate-level waste from all of Olkiluoto island’s nuclear waste facilities was started. On 20 September 2018, the Finnish Government granted operating licences for the Olkiluoto 1 (OL1) and Olkiluoto 2 (OL2) units, the interim storage for low-level waste, the interim storage for intermediate-level waste and the interim storage for spent fuel for the next twenty years, until the end of the year 2038. The granting of the operat-ing licences will make more efficient and safer handling and storage of operating waste possible, as the operating

SUMMARY

Photo: Fortum

NUCLEAR WASTE MANAGEMENT OF THE OLKILUOTO AND LOVIISA POWER PLANTS I Summary 2018 | 3

licence considers the management of operating waste in Olkiluoto as a whole, which will allow the handling of waste to be carried out, if more rational, at another plant unit than the one were the waste was generated. The li-cence specified the maximum amount of operating waste in Olkiluoto as 30 000 m3.

The majority of the objectives defined in the YJH-2015 programme for the year 2018 with regard to waste man-agement at the Olkiluoto power plant were accomplished by the end of the year. The monitoring programme for the operating waste repository (VLJ repository) has been ex-ecuted according to the plan with a more restricted sam-pling scheme after the extensive sampling programme of 2015. The monitoring results for bedrock, hydrology, groundwater chemistry, and air quality in the VLJ re-pository were reported for the year 2017 in 2018 like in previous years. The monitoring results for the year 2018 are to be reported in 2019. The research and monitoring programme for the Olkiluoto VLJ repository for the years 2018–2027 was prepared and put into action in early 2018.

VTT Technical Research Centre has an ongoing test setup in the VLJ repository for studying the microbiologi-cal corrosion of demolition waste, alongside other mate-rial research projects.

The storage for state-owned radioactive waste man-aged by STUK (Finnish Radiation and Nuclear Safety Authority) is placed in Olkiluoto’s VLJ repository under a separate agreement. The disposal of state-owned waste in the VLJ repository began in late 2016, and the disposal campaign was completed in 2017. The state-owned waste storage still has some partially empty concrete waste con-tainers waiting to be filled before their later disposal either into VLJ repository or elsewhere.

Nuclear waste management and decommissioning at Loviisa power plant

The operation of the final disposal facility for low- and intermediate-level waste at the Loviisa power plant con-tinued in 2018 like in the previous years.


The repair project for damages detected in the vault of the solidified waste cavern in 2014–2017 progressed ac-cording to plans. The renovation of the vault exterior was completed in 2018.

According to plans, decommissioning waste will be placed in specific waste storages to be excavated in the final disposal facility. The vertical silos planned for the final disposal of pressure vessels cannot be located in the previously planned area due to known horizontal fracture zones. The construction plan for the final disposal facility was updated in 2018 based on the new location.

Development needs related to the solidification plant and processing of liquid waste have been compiled into a long-term development programme (TW/TT programme). The focus in 2018 was mainly on improvements related to the handling of liquid waste, the most significant of these being the development of the Cesium separation system and the improvement of the efficiency of sewage treatment at the power plant.

In-service investigations of the final disposal facil-ity continued in accordance with the monitoring plans in 2018. The volumes of leaking water were measured most-ly in the same way as previously in different areas of the final disposal facility. As in previous years, displacements occurring in the ceilings and walls of the underground openings were very small. Once a year, a visual aggregate inspection is carried out in the final disposal facility as one part of the annual monitoring programme of ageing management. The facility was confirmed to be functional in the 2018 inspection.

The decommissioning plan for the Loviisa NPP was up-dated and submitted for a regulatory assessment in 2018. The updating process of the decommissioning plan in-cluded preparation of several reports and participation in international and national conferences and cooperation. In order to ensure that the decommissioning plans are kept up-to-date and accurate, the radioactivity levels of the

systems and structures at Loviisa NPP are monitored on a continual basis. The comments of the Ministry of Em-ployment and the Economy on the previous updating of the decommissioning plan as well as the company’s own observations for the development of the decommissioning plan were also taken into account in the updating process.

The alternative decommissioning strategies for Loviisa NPP were reassessed in 2018. The feasibility, safety, and costs of the alternative strategies were considered. The de-commissioning organisation and the management system for the decommissioning stage were also updated. The updating process further covered the radiation protection plan for decommissioning which describes the radiation protection methods to be employed during decommission-ing work phases, as well as work amounts, number of ra-diation protection staff and estimates of the accumulated doses of the employees. The activity of the pressure vessel was assessed utilising MCNP modelling. The preliminary characterisation plan for decommissioning waste was completed in 2018.

The safety case of the Loviisa final disposal facility was updated and submitted to the relevant authority for ap-proval in 2018. For the first time, the safety case covered the assessment of the long-term safety of both operating waste and decommissioning waste.

Preparation for final disposal of spent nuclear fuel

Posiva has started preparation for the submission of the operating licence application by setting up a project aim-ing at submitting the operating licence application at the end of 2021. In 2018, Posiva further developed the pro-ject plan for the operating licence project to make it more specific, and submitted the updated version of the plan to STUK for information. A meeting was organised with STUK and the Ministry for presentation of the content of the operating licence project.

Photo: Posiva


Posiva’s management system was updated in 2018 based on the changes that had taken place in the operating environment and external requirements. DNV GL Busi-ness Assurance Finland Oy AB carried out the periodic assessment of the ISO 9001:2015, ISO 14001:2015 and OHSAS 18001:2007 certificates of Posiva Oy and Posiva Solutions Oy in October 2018.

A safety culture survey was conducted during the early part of the year 2018. Compared with the previous sur-vey, the results have improved slightly. The results as well as the corrective actions were presented to Posiva’s per-sonnel in a dedicated event in April. Posiva continued to monitor the safety indices and the progress of the safety culture action plan 2018 regularly in the meetings of the Management Group.

Environmental management at Posiva is implemented by means of the certified environmental management sys-tem which also incorporates an energy efficiency system. The principle of continuous improvement is complied with in operational planning by looking for means to re-duce the potential environmental impact of the company’s operation. Development activities focused in 2018 on the collection of waste and improvement of oil separation ca-pacity, as well as materials for prevention of spills. Pre-ventive and in-service activities related to the actions of the personnel and the maintenance of the equipment were reviewed in order to minimise environmental loading.

At the engineering stage of Posiva’s nuclear facilities, attention is paid to securing nuclear and radiation safety in the design of the plant and the systems, structures, and components to verify the safe operation of the encapsu-lation plant and the final disposal facility. Posiva has adopted an established practice regarding modification procedures, incorporating an assessment of the nuclear and radiation safety significance of the proposed modifi-cation in the procedures. Assessments carried out in 2018 concerned e.g. modifications related to practices followed

in the controlled area of the final disposal facility, and to ventilation arrangements. The radiation design analyses of wall structures carried out in 2018 as part of the verifica-tion of the structural radiation safety of the encapsulation plant showed that the planned wall structures fulfil the ra-diation safety requirements specified for them.

A total of 3 inspections targeted at Posiva’s nuclear safeguards were carried out in 2018. They included an in-spection of the general description of the plant site, a safe-guards inspection included in the inspection programme of the construction stage (RTO), and an inspection of de-sign data on the final disposal facility.

Posiva uses the safety case approach to the long-term safety of final disposal. In 2018, a safety case programme was set up in Posiva’s organisation as an assembly of pro-jects that produce data for the safety case. Posiva’s safety case plan was updated in 2018 to be consistent with Po-siva’s new organisational structure and strategy.

Posiva developed a more detailed company strategy in 2018 and continued the phase to optimise the concept and the costs. The goal of this phase is the industrialisation of the project to allow safe and cost-effective implementa-tion of final disposal. One of the main themes of the 2018 strategy process was the identification of new industriali-sation activities and good ideas as part of the industrialisa-tion strategy.

Research and development of final disposal of spent nuclear fuel

Development of final disposal concept

In Posiva’s concept, engineered barriers include the copper-cast iron canister, the buffer, the backfill and the plug, and the sealing structures. The bedrock serves as a natural barrier.

Posiva continued in 2018 the definition of operating cases for the fuel data base required for regulatory safe-


guards accounting, and a test data base was installed in Posiva’s IT infra. Radiochemical isotope measurements proceeded in 2018 according to plan, with fuel isotope studies launched both in Sweden for the LO1-2 fuel and in Belgium for the OL1-2 fuel. The analyses related to fuel criticality safety and consequences of criticality pro-gressed according to plan in 2018.

The supplements and corrections that STUK had re-quired in the design-related sections of the construction plans of the copper canister components for the existing plants (OL1-2 and LO1-2) were submitted to STUK in 2018 for approval and STUK’s approval for them was ob-tained during the year. Updated lifting analyses for the fi-nal disposal canister were also submitted in this context, to demonstrate the adequate strength of the canister lid collar for lifting purposes.

The summary report of the ”Canister design analysis” project was published in the Posiva-SKB report series at the end of the year. Two studies related to the behaviour of copper in oxygen-free water were reported in 2018. The studies confirm the results of SKB’s corrosion tests in which no corrosion of copper as claimed was detected. The results were reported in 2018.

Cooperation was continued with SKB in 2018 in the de-velopment of the manufacture of the canister components. In the spring, Posiva had one copper overpack manufac-tured using the pierce and draw method. The overpack was tested against the specified requirements and subjected to comprehensive NDT testing. The overpack fulfilled all of the metallurgic requirements related to mechanical proper-ties and the microstructure. Posiva continued in 2018 with SKB the cooperation project focusing on the development of BWR type canister inserts. The project is designed to cover the manufacture of full-scale BWR type inserts and

the analysis of the structure produced in the casting pro-cess. In 2018, Posiva had one VVER insert manufactured.

The qualification documentation related to the design of the buffer was updated in the spring of 2018 based on STUK’s requirements. A decision to use a segmented buffer as a reference design was made in November 2018. It also means that the manufacturing method of the buffer blocks will change from isostatic compression to a uniax-ial compression. In addition, the engineering design of the buffer was frozen at the end of the year 2018 for purposes of the safety case. The preparation of the Design Analysis report used as background material for the construction plan continued in 2018.

Further studies into the equalisation of density differ-ences in the buffer proceeded in 2018. The studies will produce more detailed information particularly about the development of the densities and mechanical properties as a result of the bentonite blocks and pellets getting wet. A more specific determination of hydrogeochemical condi-tions was carried out from the viewpoint of the erosion process caused by the chemical forces of dilute waters, work was started to acquire the missing input data, and activities were defined for the production of empirical ma-terial for the performance analyses of the buffer and the tunnel backfill.

The qualification documentation related to the design of the backfill was updated in the spring of 2018 based on STUK’s requirements. In addition, the engineering design of the backfill was frozen at the end of the year 2018 for purposes of the safety case. The preparation of the Design Analysis report used as background material for the con-struction plan continued in 2018.

Development of the alternative backfill method (granu-lar backfill) was continued in 2018. The backfill plan was

Photo: Posiva


analysed with respect to the alternative method by updat-ing requirements and descriptions related to implementa-tion, for example. The performance of granular backfill was analysed by means of small-scale model tests. The observations made in the tests will be compared with those of the block-pellet method.

In the design of the end plug, the focus was in 2018 on the development of a plug plan for use in the Full Scale In Situ System Test (FISST).

The Full Scale In Situ System Test (FISST) set up in the rear part of the demonstration tunnel in ONKALO®

comprises two deposition holes with buffers and canisters, about 50 m of tunnel backfill, and the end plug for the deposition tunnel. Underground construction including excavation and test instrumentation were completed in early 2018 making the tunnel ready for the FISST set up.

The components used, excluding the plug, were manu-factured in the development projects focusing on compo-nent manufacturing techniques and the installation of the components was carried out utilising prototype installation equipment manufactured by Posiva. The first component in-stallation phase comprised the installation of the buffer and the canister in the deposition holes. One of the deposition holes was reserved for large buffer blocks produced with the isostatic method, and the other for smaller segmented buffer blocks manufactured using the uniaxial compression method. The installation phase in the deposition test holes was completed in August 2018. It was followed by the in-stallation of the tunnel backfill, carried out using the block backfill installation equipment. The 50 m of tunnel backfill was completed by the end of the year 2018.

Bedrock

The Olkiluoto site and bedrock have been explored for the purposes of final disposal of nuclear waste since the 1980s.

In 2018, information was gathered from new under-ground openings and boreholes for modelling and rock suitability classification. A pilot hole was drilled in the front part of central tunnel 5 in July-August. The drilling operation was delayed from the plan, because the need for pre-grouting was higher than expected in the area of the penetrations of structures OL-BFZ045 and OL-BFZ300. The planned geoscientific studies and measure-ments were carried out in the pilot hole of the central tunnel, and used as the basis for the single-hole interpre-tation which was completed in September. The research material acquired from the hole became available in full in November.

In 2018, rock suitability classifications were conducted in the area were the integrated systems operation test is carried out as well as in the area of the northern deposi-tion panel. The third rock suitability classification of the integrated systems operation test area was carried out in June. It was also possible to continue, at the same time, the

comparison of classifications at different phases as well as the comparison of prediction-outcome in RSC. For the area of the northern deposition panel, rock suitability clas-sification was carried out in the autumn when the material from central tunnel 5 became available.

The long-term safety guidelines for drilling operations were updated in 2018. A total of 31 holes with a total length of 2322 metres were drilled for the purposes of re-search and construction of the repository.

Due to the large amount of underground construction activities in 2018, the management of water inflows re-quired active control and development. New modelling analyses were made regarding the limit values applied in water inflows, and this resulted in the updating of the limit value for pre-grouting in the central tunnels.

In 2018, the LOUHI team was set up, tasked with con-trolling and developing guidelines and methods for the management and measurement of the excavation damaged zone (EDZ) in the bedrock. The team also deals with any deviations related to EDZ.

Work on the characterisation of the bedrock on the final disposal site is primarily carried out in the site descrip-tion projects. In 2018, site description activities focused with respect to the surface environment on reviewing and reporting of material. During the year, work progressed on ecosystem reports which compile and summarise the sur-face environment studies of previous years into separate reports for each ecosystem.

The third version of the discrete fracture network model which covers the entire site (ODFN3) was completed dur-ing the year. It combined in the model, for the first time ever, both geological and hydrogeological properties that describe rock deformation.

Hydrogeological and hydrogeochemical evolution modelling is used to describe the evolution of the hydro-geochemistry of the bedrock groundwater in Olkiluoto, from 8000 years ago to before the start of the construc-tion of the repository for spent nuclear fuel. The definition of input data for modelling and the building of the model (parameterisation) were ongoing in 2018.

Olkiluoto Site Description was worked on during the year in the meetings of the Olkiluoto Modelling Task Force (OMTF).

Monitoring programme

As a rule, monitoring studies proceeded in 2018 on the schedule presented in the Olkiluoto monitoring pro-gramme and the YJH-2015 programme. Activities were also focused on the development of guidelines and proce-dures for monitoring. In addition, the updating of monitor-ing action limits which was prepared in 2017 was adopted as of the beginning of 2018.

Rock-mechanical monitoring continued mostly as in previous years. Microseismic activity on the site de-


creased in 2018 over the previous year owing to the re-duced amount of excavation work.

Monitoring related to hydrology and hydrogeology continued as in previous years, as a rule, with monitoring focusing on water inflows in the disposal facility, bedrock groundwater pressure, groundwater level in the soil, and interactions between these. Excavations in the disposal facility have not resulted in any considerable decrease in groundwater level, but the previously detected decreas-ing trend of hydraulic head continued in part of the zones which are connected to the underground facilities and con-duct bedrock water.

Monitoring in the field of hydrogeochemistry was pri-marily implemented in accordance with the sampling plans. The focal area of the studies was the monitoring of salinity changes and phenomena related to sulphate reduction. Dilution has continued in the HZ20 zone and groundwater samples have shown increased sulphide lev-els in Olkiluoto indicating mixing of different groundwa-ter types.

The monitoring of the surface environment followed the guidelines of the planned programme. The sampling programme of surface waters, noise measurements, con-tinual monitoring of weather conditions, snow measure-ments, and sampling from bore wells continued in 2018. The monitoring of surface runoff also continued, based on continually operating measuring weirs installed in ditches for automatic measurement of runoff volumes and water quality.

An analysis of the occurrence of sulphate in surface water and shallow groundwater in soil indicated that the interaction between crushed rock and water in oxidising conditions is the obvious cause of the increased sulphate levels found in shallow groundwater. Nitrate levels started to decrease in the sedimentation pool and the ONKALO® drainage ditch during the year 2018. No changes were recorded in the environmental status in the conservation area of the old forests south of the ONKALO® site or in Natura2000 nature conservation areas. Posiva’s operations have not been found to have had any adverse environmen-tal impacts.

The development of the monitoring of engineered bar-riers continued in 2018 both as Posiva’s own R&D efforts and as part of the Modern2020 project funded by EU. Posiva’s Full Scale In Situ System Test (FISST) also in-volved development work related to the monitoring of the barrier components.

Safety case and research to substantiate it

The safety case is in the operating licence application presented as a report portfolio (TURVA-2020) and the reports included in it are to be published at the latest in connection with the submission of the operating licence application. Account has been taken in the plan of YVL

Guides, the Nuclear Energy Act and Decree, and STUK’s requirements. The methodology for the safety case and the content of the reports included in the safety case were presented in the safety case plan published in 2017. The uncertainties of the safety case plan are addressed in the report titled Plan for Uncertainties Assessment published towards the end of 2018.

The preparation of the main reports for the TUR-VA-2020 report portfolio progressed in 2018 according to plans, in most cases. In addition to the reports, three data management systems were developed and put in place for the management of data associated with the safety case.

The definition of the future development of the climate is a key part of the work related to the safety case, as climate conditions determine the input assumptions and boundary conditions for site evolution and thereby for the development of the final disposal repository. The long-term (1 million years) climate forecast was completed in 2018. According to the forecast, Olkiluoto will experience a glaciation cycle 8−9 times during the next one million years.

The verification of the permafrost model based on the measurement results of the ”Greenland analogy” project was finalised in 2018. The water sampling campaign planned for the year 2018 in the ongoing programme of three boreholes in the Saimaa project was implemented. The collection of input data for virtual modelling was also started in the autumn. At the end of the year, the definition of surface boundary conditions was also started for pur-poses of modelling, as well as the testing of the assump-tions by implementing a few different calculation cases.

Studies designed for a survey of the current status of the surface environment were carried out as studies as-sociated with environmental monitoring and included in the Olkiluoto monitoring programme, and also as studies producing input data for the transport modelling required for the safety case. The results of the research carried out in the Olkiluoto monitoring programme are once a year compiled into annual environmental monitoring reports.

Research activities extend beyond Olkiluoto and its im-mediate surroundings, into the reference area, because all the ecosystems which are essential to the safety case, or their different evolutionary stages resulting from land up-lift, are not found in Olkiluoto at present. No new field studies were carried out in 2018; instead, the focus was on reporting research activities carried out in previous years.

Design and implementation of encapsulation plant and final disposal facility

Excavations for the base of the encapsulation plant were completed in 2018 and a review was carried out of readi-ness to move forward to foundation works. The raise bor-ing of the canister shaft and the installation works required in the hoisting equipment building to allow it to be used


Photo: Posiva

for worksite purposes during the construction of the en-capsulation plant were started.

Engineering design of the encapsulation plant con-tinued in 2018. A management contract was selected as the contract form for the construction of the encapsula-tion plant, and the preparatory phase of the construction project was started in the autumn in cooperation with the selected contractor. The design of structural and auxiliary

systems proceeded during the year. The implementation planning phase of the main equipment for the plant was also continued in 2018 (e.g. canister lift, bridge crane for the receiving area, transfer trolleys for the canister and the fuel transport cask).

In 2017, the engineering design of the final disposal facil-ity focused on the optimisation of the various rooms and systems, which made additional and modification design


Photo: Posiva Oy

necessary. Rock engineering for the repository was contin-ued with respect to reinforcement planning of the vehicle access tunnels, the central tunnels, the deposition tunnels as well as personnel and canister shafts. Rock suitability clas-sification progressed to the area of the central tunnels where the first central tunnel pilot was drilled. System design for the disposal facility focused mainly on HVAC, electrical and automation design in order to enable works included in the building contract and building services contract to be started in the technical facilities and vehicle access tunnels.

The rock engineering designs for the central tunnels were submitted to STUK for approval at the end of 2017, and the documentation was supplemented in July 2018. STUK found some shortcomings in the designs and discontinued the review procedure in October 2018. Corrective actions

to revise the designs and their background documents were started in September. The first bundle of updated design documents was resubmitted to STUK in December.

In early 2018, a significant problem was identified in the installation and functionality of the original reinforcement structure of the personnel shaft. Implementation design of an alternative reinforcing solution was commenced, which delayed the start of the reinforcement works.

The raise boring of the canister shaft was started in the spring of 2018. While raise boring was carried out in the upper sections, injection activities were completed in the lower sections. Final completion of raise boring will not take place until early 2019.

The commissioning of Posiva’s nuclear facilities can be considered to comprise three main phases: commis-



sioning tests on component and system level, the inte-grated systems operation test, and nuclear commissioning. Commissioning stage design continued in 2018 with the preparation of the first version of Posiva’s Commissioning Manual which defines the structure of the Commissioning Manual, the documents included in it, and the procedures to be followed in their preparation.

Updated versions of the production plan were produced in 2018 as part of the planning of Posiva’s operational ac-tivities. The most significant change compared with previ-ous versions is the increased level of detail and realism at the production phases.

Work instructions and installation report templates were drawn up for installation activities related to FISST. In addition, experiments related to the use of work orders

for work management as well as the production of qual-ity control documents were conducted during FISST. The same basis was utilised to prepare the first versions for rock suitability classification and rock construction as well as work instructions related to the encapsulation plant.

Investigations were continued in 2018 into the utilisa-tion of TVO’s existing waste management systems for the sorting of low- and intermediate-level operating wastes from the encapsulation plant and their final disposal in TVO’s VLJ repository. The possession, handling, and storage of operating waste from Posiva using the systems of the OL1 and OL2 units has been taken into account in the operating licenses granted to TVO in 2018 for these units. The operating licence application for OL3 which is currently under review also takes this matter into account.

Cov

er p

hoto

: Po

siva

Oy

Posiva OyOlkiluoto, FI-27160 Eurajoki

Finlandtel. +358 2 8372 31

www.posiva.fi

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NUCLEAR WASTE MANAGEMENT OF THE OLKILUOTO AND … · 2 | NUCLEAR WASTE MANAGEMENT OF THE OLKILUOTO AND LOVIISA POWER PLANTS I Summary 2018 This report is the report referred to in