Hinkley Point C Development Consent Order Application

Hinkley Point C Development Consent Order Application

Environmental StatementDoc Ref 4.14October 2011

Environmental Statement - Annex 2Construction Method Statement

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CONSTRUCTION METHOD STATEMENT


Construction Method Statement | October 2011 1


CONTENTS 1. INTRODUCTION.............................................................................................................3 1.1 Purpose ...........................................................................................................................3 1.2 Related Documents .........................................................................................................4 2. STRATEGIC CONSTRUCTION PROGRAMME .............................................................5 2.1 Introduction......................................................................................................................5 2.2 HPC Project Construction Programme............................................................................6 3. ENABLING AND PRELIMINARY WORKS ....................................................................11 3.1 Introduction....................................................................................................................11 3.2 Enabling Works .............................................................................................................11 3.3 Preliminary Works .........................................................................................................11 4. CONSTRUCTION OF HPC ...........................................................................................17 4.1 Introduction....................................................................................................................17 4.2 Land Use .......................................................................................................................17 4.3 Temporary Buildings and Structures .............................................................................19 4.4 Construction Programme and Phasing..........................................................................22 4.5 Construction Activities ...................................................................................................25 4.6 Construction Logistics ...................................................................................................39 5. ROLE OF THE ASSOCIATED DEVELOPMENT SITES ...............................................47 5.1 Introduction....................................................................................................................47 5.2 Individual Sites ..............................................................................................................47 6. CONSTRUCTION OF ASSOCIATED DEVELOPMENTS .............................................61 6.1 Introduction....................................................................................................................61 6.2 Temporary Buildings and Structures .............................................................................61 6.3 Individual Sites ..............................................................................................................61 7. HIGHWAY IMPROVEMENTS .......................................................................................75 8. CONSTRUCTION AND ENVIRONMENTAL MANAGEMENT.......................................77 8.1 Introduction....................................................................................................................77 8.2 Construction Management ............................................................................................77 8.3 Environmental Management during Construction..........................................................78 9. EMERGENCY ARRANGEMENTS ................................................................................81 9.1 Introduction....................................................................................................................81 9.2 Emergency Requirements .............................................................................................81 9.3 Access to the Sites ........................................................................................................81 9.4 Impact on Existing Routes.............................................................................................82

TABLES Table 4.1: Proposed Areas of Land Use during the Peak Phase of Construction ......................19 Table 4.2: Construction Related Buildings and Structures: Height Parameters .........................20 Table 4.3: Approximate Distribution of Workers between Shifts.................................................42 Table 4.4: Shift start/finish times Monday to Friday.................................................................42 Table 4.5: Shift start/finish times Saturday Morning ................................................................43


2 Construction Method Statement | October 2011


Table 4.6: Shift start/finish times Alternate working pattern, all days worked..........................43

PLATES Plate 2.1: Hinkley Point C Developments Key Plan .....................................................................7 Plate 2.2: Indicative Phasing Schedule Hinkley Point C and Off-site Associated Development 8 Plate 2.3: Profile of Workforce Numbers Over Time ....................................................................9 Plate 4.1: HPC Accommodation Campus...................................................................................31 Plate 4.2: Workforce Profile........................................................................................................41 Plate 5.1: Bridgwater A Accommodation Campus......................................................................49 Plate 5.2: Bridgwater C Accommodation Campus .....................................................................50 Plate 5.3: Cannington Bypass ....................................................................................................53 Plate 5.4: Cannington Park and Ride Facility .............................................................................54 Plate 5.5: Combwich Wharf Refurbishment and Extension and Combwich Freight Laydown

Facility........................................................................................................................55 Plate 5.6: M5, Junction 23 Park and Ride Facility, Freight Management Facility, Consolidation

Facility for Courier Deliveries and Induction Centre...................................................56 Plate 5.7: M5, Junction 24 Park and Ride Facility, Freight Management Facility, Temporary Consolidation

Facility for Postal/Courier Deliveries, and Temporary Induction Centre ...................................59 Plate 5.8: Williton Park and Ride Facility....................................................................................60

FIGURES Figure 4.1: Hinkley Point C Indicative Construction Activities early 2013 Site Layout Plan

Regulation 5(2)(O) Figure 4.2: Hinkley Point C Indicative Construction Activities 2014 Site Layout Plan Regulation

5(2)(O) Figure 4.3: Hinkley Point C Indicative Construction Activities 2015 Site Layout Plan Regulation



5(2)(O) Figure 4.6: Hinkley Point C Indicative Construction Parameters 2019 Site Layout Plan

Regulation 5(2)(O) Figure 4.7: Hinkley Point C Indicative Construction Activities Sections A-A, B-B, C-C, and D-D

Site Layout Sections Regulation 5(2)(O)

APPENDICES Appendix A1: Site Preparation Works: Project Description Appendix A2: Temporary Jetty Development: Project Description Appendix A3: Construction Lighting Strategy




1. INTRODUCTION

1.1 Purpose

1.1.1 This document, together with its appendices, describes the programme and methodology for constructing Hinkley Point C (HPC), and supports the application to the IPC for Development Consent as well as providing information for the Environmental Impact Assessment. The scope of this document is as follows:

1.1.2 Section 2 describes the strategic construction programme for the HPC Project, including strategic construction assumptions.

1.1.3 Section 3 describes any applications separate to the DCO application for works on-site prior to the main construction phase, including the enabling and preliminary works to facilitate the construction of HPC.

1.1.4 Section 4 sets out the detailed programme and key construction phases for the construction of HPC. A description is provided for the key construction activities including proposed land used, construction machinery and site facilities.

1.1.5 Section 5 describes the need for and role of each of the associated developments during the construction of HPC, including the timing of the introduction of the facilities at these sites.

1.1.6 Section 6 describes the methodology for constructing and decommissioning each of the associated developments associated with HPC, including the accommodation campuses, park and rides, freight management facilities, Cannington bypass and Combwich Wharf.

1.1.7 Section 7 describes the minor highway improvements to be undertaken in support of the development.

1.1.8 Section 8 describes the construction and environmental management arrangements that would be employed to ensure comprehensive control of safety and protection of the environment.

1.1.9 Section 9 describes the emergency arrangements which would apply to the main construction site during construction.

1.1.10 Appendix A1 describes the site preparation works as submitted in the application for planning consent.

1.1.11 Appendix A2 describes the temporary jetty as submitted in the application for a Harbour Empowerment Order.

1.1.12 Appendix A3 is the Construction Lighting Strategy.




1.2 Related Documents

1.2.1 This document makes reference to, and should be read in conjunction with the following documents:

Hinkley Point C Development Site Design and Access Statement. Post Operational Strategy (Appendix to the Planning Statement). Accommodation Strategy. Hinkley Point C Development Site Environmental Management and Monitoring

Plans (Environmental Statement, Annex 3). Off-Site Associated Developments Environmental Management and Monitoring

Plans (Environmental Statement, Annex 4). Waste Management Implementation Strategy (Environmental Statement,

Annexe 5). Community Safety Management Plan (Environmental Statement, Annexe 6). Transport Assessment (Environmental Statement, Annex 7). Freight Management Strategy (Transport Assessment Appendix 1). Framework Travel Plan (Transport Assessment Appendix 2).




2. STRATEGIC CONSTRUCTION PROGRAMME

2.1 Introduction

2.1.1 This Section presents the strategic construction programme for the full HPC Project, including the HPC development site and all of the associated developments.

2.1.2 The overall programme for the construction of HPC, including the preliminary works, is anticipated to take approximately nine years and includes:

the site preparation works;

construction and subsequent operation of the temporary jetty;

construction of the sea wall;

construction of HPC, including the nuclear island, conventional island, the balance of plant, ancillary buildings and structures, the National Grid 400kV substation and EDF Energy overhead line transmission infrastructure;

construction of the cooling water infrastructure;

construction of interim storage facilities for spent fuel and intermediate level waste

construction of the on-site accommodation campus;

dismantling and removal of the temporary jetty;

removal of the on-site accommodation campus; and

landscape restoration.

2.1.3 EDF Energy has identified a number of associated developments which are considered necessary to facilitate the construction, and in some instances, the operation of HPC and to mitigate potential environmental impacts associated with the HPC Project. In the absence of the proposed associated developments, the likely traffic and socio-economic impacts associated with the construction and operation of HPC would be significantly greater in the local area. The proposed associated developments include:

Accommodation campuses in Bridgwater.

Park and ride facilities close to Junctions 23 and 24 of the M5 motorway, and at Cannington and Williton.

Freight management facilities, courier consolidation facilities and an induction centre close to Junction 23 of the M5 motorway.

Freight management facilities and temporary courier consolidation facilities and induction centre close to Junction 24 of the M5 motorway.

A bypass around the west of Cannington to minimise the amount of construction traffic using the local road network within the village.




Refurbishment of the existing Combwich Wharf facility to accommodate the arrival of approximately 180 Abnormal Indivisible Loads (AILs) and other construction related goods, over a period of approximately six years. A freight laydown facility would also be provided adjacent to Combwich Wharf.

2.1.4 Further details of the associated developments and their construction are provided in sections 5 and 6.

2.1.5 A number of minor highway improvements are proposed as part of the overall development and these are described in section 7.

2.1.6 A plan showing the locations of the various elements of the development is provided as Plate 2.1

2.2 HPC Project Construction Programme

2.2.1 As illustrated in Plate 2.2, the HPC construction programme is anticipated to commence with the site preparation works in late 2011, followed by the main construction in early 2013, through the Development Consent Order granted by the IPC. The overall construction of HPC is anticipated to take approximately nine years, with the first UK EPR reactor unit operational in 2019, and the second UK EPR reactor unit operational approximately 18 months later in 2020. However, completion of the spent fuel store would extend some two years beyond initial operation of Unit 2.

2.2.2 Some landscaping works to the south of the southern construction area would be undertaken early in the construction phase to establish final ground levels and provide early screening of the construction works for the residents to the south of the development site. In addition, landscape screening would be provided along the western boundary of the development site.

2.2.3 The final landscape restoration works would commence once the construction phase is complete and HPC is operational. Initially the temporary working areas would be cleared, including the on-site accommodation campus, and then the HPC Development Site would be landscaped which would take up to three years to complete.

2.2.4 Anticipated key dates for HPC construction are set out below, and are based on securing prior consent for the site preparation works and construction of the temporary jetty.

Commence site preparation works late 2011;

Commence construction of the temporary jetty in the second quarter of 2012;

Construction of HPC commences (subject to the grant of Development Consent) in early 2013;

Jetty completion and commissioning in mid 2013;

Completion and commencement of operation of the first UK EPR reactor unit in 2019;

Completion and commencement of operation of the second UK EPR reactor unit 18 months following the first unit;




Plate 2.1: Hinkley Point C Developments Key Plan




Plate 2.2: Indicative Phasing Schedule Hinkley Point C and Off-site Associated Development




Dismantling and removal of the temporary jetty in 2021;

Completion of the spent fuel store in 2022; and

Restoration of the HPC Development Site within two to three years of the second UK EPR reactor unit becoming operational.

2.2.5 This schedule is based on the assumption that the temporary jetty would be granted consent and construction would commence mid 2012. The jetty would take approximately 14 months to construct, which includes a period for delays in the construction programme as a result of any adverse weather conditions (weather risk). As such, there is expected to be a period of up to six months between the start of the main construction works and completion of the jetty construction; during this period materials would be transported to the site via the road network.

2.2.6 In the event that the jetty works are not consented ahead of DCO, the jetty construction would be undertaken in parallel with the main construction works.

2.2.7 The construction schedule for the main development and each of the associated developments is provided in Plate 2.2. Further details of the associated development construction are provided in Section 6.

2.2.8 This schedule provides the basis on which the profile of workforce numbers over time is estimated. This is illustrated in Plate 2.3 below.

Plate 2.3: Profile of Workforce Numbers Over Time




2.2.9 The Accommodation Strategy addresses the capability of existing local accommodation to house construction workers and defines the need for and size of accommodation campuses for workers, resulting in an on-site campus at Hinkley for 510 persons and two campuses in Bridgwater for 850 and 150 persons, as described in Section 5.

2.2.10 The remaining workers would be distributed around the local area and the geographical distribution is predicted using a gravity model in the Transport Assessment. This assessment has identified the need for park and ride facilities as part of an integrated approach to worker transport and indicates the required capacities for park and ride sites at Williton, Cannington and Junctions 23 and 24 of the M5, as described in Section 5.

2.2.11 Materials usage profiles are also derived from the construction schedule and are given in the Freight Management Strategy. In conjunction with the Transport Assessment this document indicates the need for and scale of freight management facilities required at Junctions 23 and 24 of the M5 and the freight laydown facility adjacent to Combwich Wharf as described in Section 5.

2.2.12 The Transport Assessment has indicated the desirability of a number of road improvements including a new bypass around Cannington and various highway works. The Cannington bypass would be a significant development in its own right and is included as one of the associated developments in Section 5. The highway works are described in Section 7.




3. ENABLING AND PRELIMINARY WORKS

3.1 Introduction

3.1.1 There are a number of works that are in the process of being undertaken, or are proposed to be undertaken, before the start of the main HPC construction activities. The former are termed Enabling Works and the latter Preliminary Works.

3.2 Enabling Works

a) Remediation Project

3.2.1 In January 2011 planning permission was granted by Somerset County Council for the remediation of land in the north-eastern corner of the site.

3.2.2 In addition to these remediation works, the development includes the creation of temporary areas of hard-standing for material segregation and stockpiling, plus temporary offices. It also includes construction of a temporary helipad.

b) Bat Barn Construction

3.2.3 There are a number of derelict barns located within the HPC site which would have to be demolished when the site is cleared. There are suspected bat roosts located within these barns and therefore a new bat barn is to be created to re-house them.

c) New Hinkley Point B Car Park

3.2.4 A new car park has been constructed in the north-eastern corner of the HPC site within existing operational land associated with Hinkley Point B. The new car park is the subject of a Certificate of Lawful Use or Development from West Somerset Council.

d) Trenching Works and Testing

3.2.5 There are two temporary trenches that have been excavated within the north-western part of the HPC site for vibration testing and compression testing.

3.3 Preliminary Works

3.3.1 To facilitate the construction of a new nuclear power station at HPC, EDF Energy submitted two applications to undertake Preliminary Works at the HPC Development Site, comprising site preparation works and the construction and operation of a temporary jetty. These applications were submitted to West Somerset Council

3.3.2 (WSC) and the Marine Management Organisation (MMO) respectively.

3.3.3 The preliminary works are designed to be reversible so that the land could be returned to its previous use in the event that the Development Consent Order for the HPC Project is refused. Reinstatement proposals were included in each application and the impacts associated with any reinstatement works have been assessed.




3.3.4 On the advice of the Marine Management Organisation, the proposed Harbour Empowerment Order that would permit the construction and subsequent operation of the jetty does not include provision for its subsequent removal. If a DCO for the HPC Project is not granted, EDF would seek all necessary consents to enable the jetty to be dismantled and removed and the land reinstated.

3.3.5 In case consent is not obtained for the jetty works ahead of the DCO, these works are also included within the DCO application (as are the site preparation works). The DCO application also includes for the dismantling and removal of the temporary jetty at the end of its operational lifespan.

3.3.6 If the jetty works application is not granted ahead of DCO, the HPC Project schedule would need to be adjusted to take this into account.

3.3.7 There follows a summary of the proposals for the site preparation works and the temporary jetty. Description documents from these stand-alone applications are provided in Appendices A1 and A2 respectively. If both the site preparation works and temporary jetty are consented, their work scopes would be integrated as far as possible (see Section c below: Integration of Work Programmes for further details).

a) Site Preparation Works

3.3.8 The stand-alone proposals for the site preparation works include:

Site establishment works, including the creation of construction compounds and associated facilities including welfare facilities and offices, layover facilities, car parks, and services upgrades including construction of an 11kV substation and the laying, replacement and/or diversion of services networks across the site;

Erection of construction fencing around the perimeter of the development site, and site clearance works including the diversion of rights-of-way, demolition of three existing barns; archaeological mitigation works and the removal of all of the woodland and the majority of hedgerows within the construction areas;

Earthworks to create the platforms required for the construction of HPC and commence the deep excavations for the power stations (down to 3m AOD and 6m AOD centred on units 1 and 2 respectively. It is estimated that approximately 2.3 million m3 (unbulked) of material would be excavated in total during the site preparation works and used for construction of the level platforms or stockpiled on-site for re-use. The proposed stockpile areas and stockpiling methodologies are determined by the volumes and properties of the materials, requiring the different types of materials to be stored in separate stockpiles and managed accordingly. It is anticipated that on average approximately 200,000m3 (unbulked) of material would be excavated within the application site per month throughout the site preparation works, based on the sequencing of works around the site and the transport of excavated materials. The sequence of the excavations and stockpiling is generally based on the following events:

removal of topsoil to storage areas;

removal of subsoil and overburden to storage areas, dependent upon their individual properties;




creation of screening bunds and landscaped areas, using subsoil, overburden and topsoil as required;

removal of weathered rock to storage areas or to form platforms; and

removal of fresh rock as required to storage areas or to form platforms.

All the material excavated during the earthworks would remain on-site as part of the platforms, stockpiles or landscaping.

Culverting of Holford Stream to allow for creation of a construction platform area. The culvert would be constructed from a point adjacent to the western boundary of the site, across to the eastern boundary of the site, where it would return water into the existing open Holford Stream watercourse.

Construction of a surface water drainage system incorporating water management facilities, outfalling into Bridgwater Bay and Holford Stream ensuring that:

water is discharged at controlled rates (greenfield run-off rates being achieved for discharges into Holford Stream downstream of the site).

all surface water discharges meet appropriate water quality standards in terms of suspended sediments and other possible contaminants (e.g. hydrocarbons);

the drainage is designed using the principles of Sustainable Drainage Systems (SuDS), including re-use wherever possible; and

the design for the drainage strategy is based on a 1 in 30 year storm event occurring during the construction period.

The surface water drainage system would incorporate modular foul treatment facilities to serve the construction workforce. These facilities would be installed during site preparation but would not be used until the HPC works commence.

Dewatering of the working areas around the areas proposed for deeper excavations during the main construction phase. Water collected from dewatering would be discharged to the surface water drainage system described above.

Construction of a temporary retaining structure along part of the northern edge of the main platform to retain the elevated main platform above the natural grade level (this structure being subsumed by the sea wall within the HPC works).

Development of a network of haulage roads to facilitate the movement of vehicles and soil and rock materials around the site, including:

a north-south haulage road which would allow for the transfer of excavated material to the southern part of the site;

a haulage road network in the northern part of the site, which would vary in location and level to suit the ongoing platform development to eventually tie into the site compounds as they are developed;

a service road around the perimeter of the site within the security fence to facilitate the construction of the fence and allow security and maintenance personnel access to inspect and maintain the fence line; and

a foreshore access road from the site at a gap in the cliff. During the site preparation works this foreshore access road would be used only for a limited period to complete the outfall construction works on the foreshore.




Construction of site access points to the north-east of the site to provide the main site access during the site preparation works, with a second site access gate to the south-east of the site to provide access for Heavy Goods Vehicles (HGVs) and deliveries to the site. Two roundabouts would be constructed to the north-east and south-east of the site to serve these access points.

Installation and commissioning of two concrete batching plants; the smaller of these would be used for concrete for the preliminary works, the other would not be used for concrete production with the exception of concrete tests until the Development Consent Order is granted.

b) Temporary Jetty

3.3.9 The stand-alone proposal is for the construction and operation of a temporary jetty extending off the north-west coast of the construction site including:

Erection of construction fencing around the onshore development site;

Construction of haulage roads, including access to and along the foreshore to facilitate construction of the works on the foreshore;

Soil stripping and topsoil, subsoil and overburden storage;

Construction of the onshore development platform for the jetty;

Surface water drainage and treatment infrastructure for the platform;

Piling for the jetty bridge and head, using tubular steel piles. The piles would be inserted using either the drill and drive technique or into pre-drilled sockets where they would be grouted into place. The onshore and foreshore piles would be inserted using land-based equipment. The offshore piling would use a jack-up barge;

Construction of the jetty bridge, incorporating a roadway and conveyors for aggregates, sand and cement;

Construction of the jetty head, incorporating ship mooring provisions, aggregate and cement receipt equipment and facilities for jetty workers;

Dredging of a berthing pocket alongside the jetty head to allow ships of up to 5,000 deadweight tonnes (dwt) to berth;

Construction of onshore storage stockpiles for aggregate (both external and internal within a sand shed) and silos for storage of cement;

Compulsory acquisition of certain land interests required for these works; and

Materials and construction equipment deliveries would be predominantly by sea for the offshore works and by road for the onshore and foreshore works.

c) Integration of Work Programmes

3.3.10 Whereas the applications for the site preparation works and the temporary jetty are capable of being implemented independently, if consent were received for both it is intended that the work scopes would be integrated to the maximum extent practicable in order to avoid duplication of activities wherever possible.




3.3.11 The project schedule envisages that the site preparation consent would be received first and the following activities, which are common to both applications, would be implemented under the site preparation consent and therefore would not need to be implemented under the jetty consent:

Erection of construction fencing around the onshore development site;

Soil stripping and storage for topsoil, subsoil and overburden;

Construction of haulage roads, including access to the foreshore (the access corridor running along the top of the foreshore between here and the jetty site being undertaken only under and in accordance with the jetty application);

Construction of the onshore development platform for the jetty; and

Surface water drainage/treatment infrastructure serving the development platform.

3.3.12 In this scenario there would be no need to develop the rock extraction area or the east-west service road between the onshore jetty site and the site entrance, as described in the jetty application. With the site preparation works consented, the site-wide cut-and-fill balancing would apply making the rock extraction zone redundant, and the haul routes would follow different alignments taking account of the terracing during site preparation. The soil storage areas identified in the jetty application would also not be needed because the soil strip would occur during site preparation and the soils would be stored in the areas identified in the southern part of the HPC development site.

3.3.13 The water management zone included in the jetty application would not be required as the jetty site would instead be served by the construction drainage installed during site preparation (i.e. the spine drains discharging to Bridgwater Bay).

3.3.14 No on-site footpaths would need to be stopped up to construct the jetty if the site preparation works are also consented, because in this scenario all footpaths crossing the HPC development site would be diverted onto an alternative route running around the perimeter of the site outside of the construction fence. The coast path would be closed when the earthworks start and would re-open once the sea wall is constructed if the DCO is granted. The jetty has been designed to safely accommodate the coast path running beneath it during the operational phase of the jetty.

3.3.15 The Site Preparation Works and Temporary Jetty descriptions (Appendices A1 and A2) include the removal and reinstatement activities to be undertaken in the event that the power station construction does not proceed. In the event that DCO is granted and the power station is constructed, this reinstatement would not take place and the DCO restoration works would be undertaken instead.




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4. CONSTRUCTION OF HPC

4.1 Introduction

4.1.1 This section provides a description of land uses and key construction activities at the HPC development site. The site comprises an area of land to the west of the existing Hinkley Point A and Hinkley Point B power stations, between the village of Shurton to the south and the coast to the north.

4.2 Land Use

4.2.1 This section describes the main land usage throughout the construction works.

4.2.2 The overall construction site area is bisected by a track (Green Lane) running east-west, which has landscape, archaeological and ecological significance. This track would be retained and protected for most of its length and two crossing points are provided for construction traffic.

4.2.3 The southern limit for main construction activity has been set as OS grid line 144750mN, to provide a buffer zone between the main construction activity and the village of Shurton. However, limited works (early landscaping and the construction of an emergency access road and associated bridge over Bum Brook) would take place within this buffer zone.

4.2.4 A number of badger setts have been relocated to the west of the construction site. These badger setts, together with a bat house, earth bunds and water management zone(s) would be integrated into a landscaped western boundary, which serves to reduce the visibility of the works from the west.

4.2.5 A temporary jetty would be located in the north-west of the site to facilitate the import of bulk materials, primarily aggregate, sand and cement for concrete production and other construction materials.

4.2.6 An on-site accommodation campus would be located in the south-east corner of the HPC development site.

4.2.7 Construction of the permanent plant and buildings (the Permanent Development) would mostly take place in the north part of the HPC development site, above Green Lane. In order to support this construction, temporary contractor facilities and storage areas would be required to the west and south of the Permanent Development. These additional areas would include space for:

Topsoil, subsoil and excavated rock storage.

Contractors plant, storage and offices/welfare facilities.

EDF offices and welfare facilities.

Bus and car parking.

Landscaping to mitigate the visual and ecological impact of the construction activity.




Environmental management, such as management of surface water.

Access control and security.

Connecting roads and paths.

4.2.8 Access to the construction site for material deliveries by road would be from Wick Moor Drove via a roundabout into the southern part of the site. This southern access incorporates a waiting area and search lanes for delivery vehicles. Workers would mostly be bussed to site and arrive via the northern roundabout and a coach drop-off and parking area on the site of the southern permanent station car park. Workers would enter the site via turnstiles and a search hall for security control.

4.2.9 During the site preparation works, the construction areas would be levelled into a series of platforms and excavation of the main site would start. The total excavation and ground terracing works would involve the movement and storage of approximately four million m3 of material, of which about 2.3 million m3 would be moved during the site preparation works. To avoid additional road journeys, all the material would be retained on site. This would necessitate the culverting of Holford Stream to provide space for stockpiles and working platforms.

4.2.10 In the south-west corner of the site, north of grid line 144750mN, would be storage areas for topsoil, re-usable excavated rock, weathered rock and overburden. The areas for soil storage would be subdivided to segregate the various categories of material and allow multiple uses of the areas, where practicable. Topsoil storage requires limited storage height in order to avoid damaging the structure of the soil. Some of the rock would be suitable for engineered backfilling of the excavations, although pre-treatment in the form of crushing and grading would be necessary for some classes of fill. This rock, which is destined for engineered backfill, needs to remain accessible during storage. Other material, which would not be used for engineered backfill, would be stored in areas to produce level platforms suitable for accommodating temporary contractors facilities.

4.2.11 Water management zones would be located in the north, east and west of the site to control the discharge of water from run-off and dewatering activities into the sea and local watercourses. An additional water management zone may be required to the south of the southern construction area, to deal with run-off from the proposed early landscaped area. The northern water management zones would be removed as the permanent site drainage systems are implemented.

4.2.12 Areas of the site that are not required for permanent plant and buildings would be used as temporary contractors areas. Allocations would change over time and the contractors would be required to install whatever facilities they need for their workers and construction equipment and materials. Service connections for the contractors use (electricity, water, drainage) would be made available in close proximity of the contractors areas.

4.2.13 Although the construction site plans (Figures 4.1 to 4.5) show some key temporary buildings, the actual provisions and locations would be developed in conjunction with the relevant contractors. In addition, muster points, welfare and medical facilities would be provided. The locations of these facilities would need to be validated with the early contractors and many would be relocated as the work progresses.




4.2.14 The construction of the National Grid 400kV substation in the south-east corner of the permanent power station area, along with the diversion of existing overhead lines to facilitate connections to the National Grid transmission system would be undertaken by National Grids contractors as a separate activity. A temporary working area would be provided to the south and east of the substation for the duration of National Grids construction works.

4.2.15 Construction of the EDF Energy overhead transmission lines and towers on the permanent power station site would be undertaken by EDF Energys contractors.

4.2.16 The working areas for some of the contractors, such as for the marine works and substation, would be located wholly or partly within the footprint of the permanent development site. Within the development site boundary, the layout of the site would vary over the construction period but, taking this into account, the anticipated principal uses of the overall land area within the development site at the peak phase of construction, in 2016, are presented in Table 4.1 below.

Table 4.1: Proposed Areas of Land Use during the Peak Phase of Construction

Land Use Area (ha)

Final permanent power station area 67.5

Construction contractor accommodation, working and storage 28.4

Landscape screening and protected areas/reserves 27.5

Construction site entrance and access roads 20.6

Stockpile of material for re-use 13.3

Topsoil storage 9.7

On-site accommodation campus 3.7

Low-lying land unsuitable for construction use 2.8

Sea wall foreshore construction area 1.7

Total 175.2

4.2.17 The land uses would change throughout the construction phase, reflecting the different stages of development activity. For example, the area allocated to the civil works contractor would be reduced and the spare land reallocated to the main mechanical and electrical contractors as the balance of work on the site changes. The changing usage of land is illustrated in Figures 4.1 to 4.5.

4.2.18 In addition to the main construction activity, associated developments as outlined in Sections 5 and 6 would be required. One of the accommodation campuses for up to 510 workers would be located adjacent to the construction site in the south-east corner of the HPC Development Site. All the other associated development sites would be located remote from the main construction site.

4.3 Temporary Buildings and Structures

4.3.1 A range of buildings, structures, plant, equipment and uses will be required temporarily in connection with, and for the duration of, construction works at the HPC Development Site and the Associated Development sites.




4.3.2 Whilst the heights of the permanent buildings at the HPC Development Site are defined in the Hinkley Point C Development Site Design and Access Statement, the height of the temporary buildings and structures would vary across the site and would change with time. Figures 4.6 and 4.7 show in plan and cross section the height limits for various areas of the site.

4.3.3 Figure 4.6 identifies construction zones of the site within which temporary buildings and structures would be located. Figure 4.7 shows cross-sections through the site and the height limits for the various temporary buildings and structures. Table 4.2 below shows the heights limits applicable to each of the zones identified on Figure 4.6.

Table 4.2: Construction Related Buildings and Structures: Height Parameters

Construction Zone Explanation of Parameter Construction Zone Parameter (Max. Height)1

Zone 1: Construction of the main nuclear island, conventional island, balance of plant and ancillary buildings.

Working envelope for main building construction requirements. Structures to include: temporary buildings, construction warehousing and storage buildings; and tower cranes, mobile cranes and other specialised lifting equipment.

140m AOD

Zone 2: Construction of the main nuclear island and conventional island Exceptional Structures

Working envelope for exceptional structures that are required for the lifting and installation of reactor domes and other time limited activities that require specialised cranes or lifting equipment that go above the height parameters set out in Construction Zone 1. Typically these would include large mobile cranes for installation of the dome associated with the two reactor units.

175m AOD

Zone 3: Contractor areas to the north of green lane.

Working envelope for liner fabrication facilities, workshops, storage buildings, offices and mess facilities, concrete batching plants and associated aggregates stockpiles, covered stockpiles and cement/pulverised fuel ash silos.

75m AOD

Zone 4: National Grid substation area.

Working envelope for substation construction, transmission tower erection, workshops, storage buildings, offices and mess facilities.

80m AOD

Zone 5: Contractor areas to the south of green lane.

Working envelope for workshops, storage buildings, offices, mess facilities and fixed cranes.

55m AOD

Zone 5: Contractor areas to the south of green lane Exceptional Structures

Working envelope for exceptional structures in Zone 5, such as mobile cranes.

75m AOD

1 Figures quoted are height above ordnance datum level




Construction Zone Explanation of Parameter Construction Zone Parameter (Max. Height)1

Zone 6: On-site accommodation campus

Working envelope for the onsite accommodation campus.

32m AOD

Zone 6: On-site accommodation campus Exceptional Structures

Working envelope for exceptional structures in Zone 6, such as mobile cranes.

55m AOD

4.3.4 Exceptional structures comprise very large cranes and similar equipment which would be used for relatively short periods during the construction works for specific activities, such as lifting in the reactor building liner dome roof, and would then be removed.

4.3.5 Other buildings and structures include temporary buildings which would be used by the contractors for fabrication, storage, offices and welfare, as well as long-term cranes such as tower cranes. The height parameters for buildings and structures also apply to any extensions to existing temporary buildings and structures.

4.3.6 Zone 1 is the main power station area of together with the area immediately to the west which would be used by the main construction and erection contractors. Zone 2 is within Zone 1 and includes the main nuclear island, conventional island buildings and the areas immediately to the south and west where liner fabrication may be undertaken. Zone 2 is where very large mobile cranes would be used for installation of the liner roof, polar crane and main exhaust stack.

4.3.7 Zone 3 includes the area to the west of Zone 1 where aggregates, sand and cement brought in by the jetty would be stored and construction/erection contractors would site their storage and prefabrication facilities. Zone 3 also includes the area south of Zone 1 where the platform level is +20m AOD and various ancillary power station buildings would be constructed. It also includes an area for the main nuclear steam supply systems contractor would be based.

4.3.8 Zone 4 is the area of the National Grid substation at +14m AOD and includes the temporary works area for the National Grid contractors.

4.3.9 Zone 5 is the area where the main mechanical and electrical installation contractors would be based. During the early construction works, this area may also be used by the main civil works contractor for laydown and storage.

4.3.10 Zone 6 includes the southern site entrance, the on-site campus and an area for offices and laydown/storage. Maximum heights within this area would be limited in order to minimise the visual impact on the village of Shurton.

4.3.11 Soil and rock stockpiles will be within the heights shown for these areas on Figure 4.6

4.3.12 Construction lighting will be provided in accordance with the Construction Lighting Strategy as described in section 4.5 and attached as Appendix A3.

4.3.13 Internal site roads will be provided in the general locations shown on Figures 4.1 to 4.5 and as described in section 4.5




4.3.14 The HPC Development Site would be enclosed by construction hoardings, security fencing and perimeter enclosure, initially in the form and locations required for site preparation. These would be re-aligned from time to time within the confines of the HPC Development Site to take account of the construction needs at that time.

4.3.15 The above approach is considered to provide sufficient detail within the DCO to enable the temporary construction-related development to be erected without the need for prior approvals from the Local Panning Authority or Commission.

4.4 Construction Programme and Phasing

4.4.1 This Section sets out the construction programme and the key phases within this programme. Following the site enabling and preliminary works, as described in Section 3 above, the principal phases of the main construction are:

excavation for building foundations;

construction of permanent buildings and marine structures;

installation of mechanical and electrical equipment;

commissioning; and

site clearance and landscaping.

However it should be noted that these phases would overlap and construction of the second reactor unit would generally follow the first unit by 18 months. Temporary construction infrastructure would be required to support each phase.

4.4.2 Figures 4.1 to 4.5 are indicative phasing plans for the full construction phase from site preparation through to completion of HPC and land restoration. The series of plans identifies the construction activities at key phases in the construction programme; however it should be noted that these are subject to refinement of the detailed construction sequencing. It should also be noted that within the main construction site areas there would be activities and uses that would remain undefined, including minor temporary facilities and structures.

4.4.3 Figures 4.1 to 4.5 and the associated descriptions are based on the enabling and preliminary works described in Section 3 having been commenced on schedule ahead of DCO consent. In the event that any of the necessary permissions are not received prior to DCO consent, the respective works would be integrated into the main power station construction schedule as appropriate.

4.4.4 In early 2013, shortly after DCO is granted, the site would be generally as shown in Figure 4.1. A number of construction activities would have been completed or be underway as follows:

The site perimeter fence would have been erected.

The temporary jetty would be under construction, utilising a temporary beach access road.

Holford Stream would have been culverted, the north and south access roundabouts and initial haulage roads have been built and the material stockpiles are in use.




The landscaping along the western site boundary would be substantially complete.

A temporary earth retaining structure would have been built at the low-lying land near to the cliff line to enable a level platform to be established behind.

A permanent station car park would have been constructed and others would be under construction.

The main platform areas would have been established in the northern part of the site and excavation of the areas for the main plant buildings would have started.

Contractors working areas would have been established in the northern part of the site and be under construction in the southern part.

Interim security arrangements for personnel and materials deliveries are in place.

Water management zones would have been established for the management of drainage and the principal network of construction drains would be in place with an outfall to the sea shore.

Landscaping of the area south of grid line 144750mN is in progress.

4.4.5 Figure 4.2 shows the indicative layout of the construction site at the start of nuclear island construction in 2014, where:

The temporary jetty has been completed and is in use.

The sea wall in front of the permanent power station site has been constructed.

The permanent station car parks have been built. The south car park is in use for park and ride buses for the workers and part of the south-east car park has been allocated to the National Grid 400kV substation contractor as a working area.

All the principal contractors working areas have been established.

The construction of the National Grid 400kV substation has commenced.

Security access controls have been established for materials deliveries via the southern access roundabout and for workers arriving by bus to the south car park.

Site offices have been built near to the southern access roundabout. The on-site accommodation campus area has been levelled and accommodation blocks and facilities are in the final stages of construction.

The Public Information Centre and some permanent offices and ancillary buildings are under construction.

Many of the tower cranes have been erected on the main power station area.

Excavations for Unit 1 have been completed and the foundations prepared for start of construction of the nuclear island.

Construction of the marine works has started, ready to bore the tunnels for the cooling water.

Landscaping of the area to the south of the main construction area is substantially complete, and the construction of the emergency access road together with its bridge over Bum Brook is under way.




4.4.6 Figure 4.3 shows the indicative layout of the construction site in 2015, where:

The excavations for Unit 2 are complete and ready to start construction of Unit 2 nuclear island.

The offshore cooling water works are partly complete, including tunnels, access shafts and intake structures, with the discharge structures remaining to be installed.

The buildings for Unit 1 and most of the shared (Unit 1 and 2) buildings are under construction and the excavations are being back-filled.

A number of temporary buildings are complete or under construction in the contractors working areas.

The installation of mechanical and electrical equipment is under way.

The Public Information Centre, Simulator Building/Training Centre, permanent site offices and the Outage Access Control Building are complete. Temporary access to the Public Information Centre is established via the south-east permanent station car park.

The on-site accommodation campus is complete.

The National Grid substation is under construction.

4.4.7 Figure 4.4 shows the indicative layout of the construction site in 2019 when Unit 1 is in operation, where:

Unit 1 is complete and is fenced off from the rest of the construction site.

The ancillary buildings for both units are complete.

The National Grid substation is complete and National Grids transmission system connections have been diverted to connect the substation.

Unit 2 buildings are substantially complete and mechanical and electrical equipment installation is nearing completion.

The interim storage buildings for intermediate level waste and spent fuel are under construction.

4.4.8 Figure 4.5 shows the indicative layout of the construction site in 2020 when Unit 2 commences operation where:

both units of the power station are complete and fenced off from the rest of the construction site;

construction of the Intermediate Level Waste Interim Storage Building is complete, although work continues on construction of the Interim Spent Fuel Store; and

some of the contractors temporary facilities are being dismantled and removed.

4.4.9 After the start-up of Unit 2, the following activities would be undertaken:

the temporary jetty would be dismantled and removed;

the on-site accommodation campus would be closed, the buildings dismantled and removed and the area cleared;




the contractors areas would be cleared and temporary services removed;

temporary re-routing of the emergency access road would be established to allow the final landscaping to be undertaken in the southern construction area;

the internal fit-out of the Interim Spent Fuel Store would be completed; and

final landscaping and planting would be undertaken, incorporating the final alignment of the emergency access road and the visitor access road to the south car park.

4.5 Construction Activities

4.5.1 The construction would be undertaken by a number of contractors. The number of contract packages would be limited, which would maximise consistency in the management and control of site activities. Construction activities would be controlled by the use of construction method statements which would be prepared by the contractor and approved by EDF Energy prior to use.

a) Contractor Mobilisation

4.5.2 Following the grant of the DCO, the main civil works would complete mobilisation and the marine works and ancillary buildings contractors would mobilise. This would be followed progressively by the mobilisation of the other site contractors. Mobilisation would include:

induction training for site workers, including security and immigration checks, training in safety awareness and site arrangements, and signing up to the workers code of conduct prior to the issue of a site pass;

preparation and approval of construction environmental management plans;

preparation and approval of method statements for the work to be undertaken covering safety, environmental, quality and regulatory aspects;

installation of the contractors site compound facilities; and

installation and testing of key temporary plant, such as tower cranes.

b) Construction of Contractor Compound Areas

4.5.3 The contractors compound areas would be prepared as level platforms by the site preparation works contractor. Surface water drainage would be via the construction drainage systems installed during the site preparation works. Service connections for water, electricity, sewage and telecommunications would be provided in close proximity to each compound.

4.5.4 Each contractor would provide fencing and lighting for their own compound. They would install facilities for office and welfare use for their workforce, together with workshops and storage facilities as necessary, connecting these to the adjacent services connection points.

c) Site Access

4.5.5 The HPC development site would be arranged as a secure construction site with controls on the people and materials entering and leaving the site. New roundabouts




would be constructed at the southern and northern site access points during the site preparation works.

4.5.6 Most of the materials required for the production of concrete (sand, aggregate, cement and cement substitutes) would be transported to site by sea and would be offloaded at the temporary jetty. The jetty could also be used for the import of other bulk materials to the site, where this is practicable.

4.5.7 Other construction materials would be delivered by road and would enter the site via the southern roundabout. As detailed in the Freight Management Strategy, all road deliveries would be managed using a computerised delivery management system which controls the timing of deliveries. Vehicles arriving via the motorway networks would be required to check-in at one of the freight management facilities at J23 or J24 and would be despatched to site in accordance with a strict timetable. Delivery vehicles would be subject to search in line with the security policy before entry and when leaving the site. Deliveries would normally be made to the respective site contractors compound and the delivery vehicle would then leave the site.

4.5.8 Abnormal Indivisible Loads (AILs) which are subject to road transport restrictions, including major equipment items such as the reactor pressure vessel, would be delivered by sea to Combwich Wharf and would then be transported to site by road. These deliveries would bypass the southern site entrance and would be transported directly to the point of installation via the northern roundabout. All such deliveries would be subject to special controls to minimise the impact on other road users.

4.5.9 Waste and other materials despatched from site would also be subject to controls in accordance with the Waste Management Implementation Strategy. Where practicable, sea transport would be used, but most transport would be by road. The delivery management system would be used to manage the timing of freight vehicles, including empty vehicles, leaving the site to ensure compliance with the transport plan for waste and materials movements.

4.5.10 In accordance with the Framework Travel Plan, nearly all personnel working at the construction site would travel to and from site by bus. Buses would collect workers from off-site campuses, park and ride sites and other identified locations and take them via the northern roundabout to the site personnel entrance adjacent to the south permanent station car park. This car park would be dedicated to buses for the duration of the construction period, although the access route would vary according to the stage of construction works. Workers would enter the site through turnstiles adjacent to the bus drop-off point and would be subject to security controls and searches in line with the security policy. Buses to take workers home would wait within the designated car park and would leave as soon as they are full.

4.5.11 When fuel is delivered to site for Unit 1, the bus access via the northern roundabout would be closed and the worker buses would enter the site via the southern roundabout before travelling north to the south car park and personnel entrance.

4.5.12 Very limited car parking would be available during the construction period. This would be provided outside the construction site fence and no private cars would be allowed within the construction site. 200 car parking spaces would be provided for EDF Energy and construction contractors. EDF Energy and its contractors would each be allocated a small number of parking spaces sufficient to enable them to fulfil




their responsibilities for health and safety and worker welfare. In addition, there would be 100 car parking spaces allocated for visitors, including VIP visitors to the site, disabled visitors to the Public Information Centre (PIC) and coach parking for other PIC visitors. Provision for pedal cyclists would be made at the construction site, but motorcyclists would be required to use the park and ride sites.

4.5.13 Workers resident in the on-site accommodation campus would be able to enter the site via dedicated turnstiles adjacent to the campus. All other persons who do not walk or cycle to site and are not entitled to the use of one of the limited car park spaces would be required to use the bus service to the site, via the park and ride sites if necessary.

d) Internal Haulage Roads

4.5.14 During the site preparation works, a number of haulage roads would be developed on site to facilitate the movement of vehicles carrying excavation and construction materials around the site. These haulage roads are indicated on Figures 4.1 to 4.5 and would vary in location and level according to the construction needs. Where practicable, the haulage roads are aligned with the routes for the permanent roads.

4.5.15 In addition, a temporary service road would be constructed around the perimeter of the site within the security fence, to allow security and maintenance personnel access to inspect and maintain the fence line.

4.5.16 The haulage roads would be constructed in accordance with the current relevant British Standards and the Highways Agency Design Manual as required for heavy vehicle usage and estimated traffic volumes. These haulage roads would be surfaced with tarmac or compacted granular material as appropriate, and the surface water drainage would be tied into the construction drainage systems to be installed during the site preparation works.

4.5.17 Lighting would be provided along the haulage roads in line with the Construction Lighting Strategy in Appendix A3.

e) Civil Works

i. Introduction

4.5.18 The civil works would pick up from the site preparation works, completing the deep excavations before starting the building construction.

ii. Platform Development and Deep Excavation

4.5.19 Most of the platform development and ground terracing would have been undertaken during the site preparation works. However, as the deep excavations are undertaken, additional platforms and access routes would be required to facilitate access. The deep excavations would involve mainly fresh rock, although some weathered rock would be encountered. Where practicable, mechanical excavation would be used. However, blasting may be required and this would be strictly controlled, with appropriate warning given to nearby residents. The excavated material would be transported by dump truck to the designated stockpiles in the south of the site, where it would be stored in accordance with the Soil Management Plan and the Materials Management Plan contained within Annex 3 to the ES.




4.5.20 The deep excavations would require dewatering. Dewatering wells would be drilled outside the perimeter of the excavations and water would be pumped out to lower the water table locally and enable the excavation to be carried out in dry conditions. Pumping rates would be adjusted to minimise the drawdown of groundwater levels outside the excavation.

4.5.21 Excavations for Unit 2 would continue after the excavations for Unit 1 are complete and construction of the Unit 1 buildings is underway. Excavations for the interim spent fuel store would take place during the latter stages of Unit 1 construction, once the marine works are substantially complete and the area can be released.

4.5.22 Material from the excavations would be taken to the material storage areas where it would be placed and levelled to produce a temporary working platform to the east and levelled storage areas to the west.

4.5.23 Backfilling of the excavations as the buildings are constructed would be managed in accordance with the engineering performance required. Different material standards are applied depending on the location of the backfill. Where practicable, excavated material would be used for backfill and this would require careful quality control in the segregation of materials going to the stockpiles. To achieve the particle size standards required for backfill, rock crushing plant would be used. Where excavated material is insufficient or unsuitable for backfill, appropriate granular fill material would be imported.

f) Construction of the Sea Wall

4.5.24 The sea wall would be constructed to provide erosion protection for the HPC power station platform. It is located approximately along the line of the existing cliffs in front of the permanent power station site and would incorporate return sections at each end of the wall to prevent erosion from the side. A 30m wide corridor from the cliff line in the upper foreshore area would be required to construct the sea wall.

4.5.25 The West Somerset Coast Path would have been closed for the preliminary works and a new path would be constructed immediately landward of the completed wall, connecting to the existing coastal path. An access ramp down to the foreshore would be provided at the western end of the wall for inspection and maintenance. Access steps would be provided at intervals along the length of the wall to allow safe access and egress from the foreshore level.

4.5.26 The construction methodology for the sea wall would be the responsibility of the chosen contractor, but a likely construction sequence is indicated below.

4.5.27 The construction drainage outfall would be temporarily extended as necessary to allow the sea wall construction to proceed safely.

4.5.28 The existing cliff line would be trimmed as necessary to provide space for the wall construction. Rock armour would be delivered by sea and temporarily placed seaward of the works to provide protection during construction. A haulage road would be built parallel to the cliff to provide access and the foundations of the wall would be excavated.

4.5.29 The excavated rockhead would be prepared and any cracks grouted and the base concrete would be poured into prepared formwork.




4.5.30 The area for the rock armour would be excavated, covered with geotextile and the rock armour placed in position.

4.5.31 The main wall section would be cast within prepared formwork, prior to installation of the drainage works behind the wall and partial backfilling behind the wall. The construction drainage outfall would be integrated into the main wall.

4.5.32 The top section of the wall would likely be formed of pre-cast units which would be installed on top of the main wall section before completion of backfill.

4.5.33 Access ramps and steps would be cast in parallel with the main wall construction and the footpath would be created following completion of backfill behind the wall.

4.5.34 The return walls would be formed by interlocking cast-in-situ concrete piles, extending down into the underlying rock with a concrete capping beam and reinforced concrete cladding on the passive side. Pedestrian access ramps would be formed to carry the footpath over the return walls and link into the existing sections of the West Somerset Coast Path.

4.5.35 Once the construction drainage system has been decommissioned, the associated outfall structure would be removed and the sea wall would be made good.

g) HPC Accommodation Campus

4.5.36 The proposed on-site accommodation campus would provide accommodation for up to 510 workers in accordance with the Accommodation Strategy,

4.5.37 The facilities as illustrated in Plate 4.1, would comprise:

accommodation blocks; amenity buildings; access roads, car parking, cycle facilities and footpaths; external sports pitches (accessible to the public) and associated welfare facilities; security office; access to the main construction site by turnstiles; and drainage, landscaping and ecological features.

4.5.38 The on-site accommodation campus, whilst adjacent to the main construction site, would be treated as a separate construction site with limited interaction with the main site construction activities during the construction of the campus.

Preparatory Works

4.5.39 Prior to the construction works a number of preparatory activities would be undertaken, including:

site clearance, including vegetation removal; levelling of the platform for the construction of the campus; construction of a landscaped earth bund to the south of the campus; and installation of fencing around the area for the campus.




4.5.40 Construction access is proposed via a temporary section of road connected to the southern roundabout on the C182; this access would be retained throughout the duration of the main HPC construction works when the on-site accommodation campus is operational.

4.5.41 Temporary site offices, welfare accommodation, storage and site parking areas would be provided within the site.

Construction Works

4.5.42 The construction works would commence with the preparation of the platform and required excavations for the on-site accommodation campus and associated facilities. Concrete works would then by undertaken to build the foundations.

4.5.43 In parallel, the construction of the internal roads and parking areas would be undertaken. Initially these areas would be constructed up to base course and sub-base level respectively. The final layers for the roads and parking areas would be completed as one of the last works before occupation.

4.5.44 The section of road providing access to the site would be completed under supervision of the highway authority. The permanent entrance into the site, off the C182, would be constructed.

4.5.45 The surface water drainage, as well as foul and surface water connections, would be installed at the same time as the roads, parking areas and building foundations.

4.5.46 It is envisaged that the buildings on-site could be partially or wholly of prefabricated and/or modular construction on concrete foundations. The building elements, if a modular construction is used, would be delivered to the site on flat-bed vehicles, then lifted into position by mobile cranes and connected together. Where on-site steel framed construction is to be utilised, this would be assembled and fitted out with the internal mechanical and electrical services installed. The utility connections would then be made.

4.5.47 Two all weather five a side sports pitches would be constructed to the north of the buildings and the internal landscaping would be implemented.

4.5.48 Security fencing, with associated lighting and CCTV, would be erected around the perimeter of the site.

Operation and Decommissioning

4.5.49 The campus would be operated and decommissioned in accordance with the Accommodation Strategy.

4.5.50 The buildings and associated infrastructure would be removed in accordance with a demolition plan, which would maximise the potential for re-use of building, modules and materials.

4.5.51 Once the campus is removed, the area would be landscaped in accordance with the approved landscape plan.




Plate 4.1: HPC Accommodation Campus




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h) Construction of Buildings and Infrastructure

i. Nuclear Island

4.5.52 The nuclear island buildings are constructed of reinforced concrete. The concrete would be mixed on site using a batching plant and would use sand, aggregate and cement imported via the temporary jetty. In some cases, cement substitutes, such as pulverised fuel ash would be used to secure specific concrete properties. The reinforcement would be with steel reinforcing bars, fabricated into cages appropriate to the building geometry and strength requirements. Some reinforcement would be prefabricated into assemblies which can be lifted into place. Such pre-fabrication would normally take place close to the workface to minimise handling issues. Where plant or equipment has subsequently to be attached to the concrete structure, embedded attachment plates are provided and fixed to the reinforcement cage in such a way that they are able to transmit the loads of the attached equipment into the concrete.

4.5.53 Temporary formwork either of steel and/or wood would be used to create a mould around the reinforcement, into which the concrete is pumped. A small number of key concrete pours would need to be completed as a continuous activity spanning several shifts. Local residents would be given prior warning of these activities which would involve 24-hour working.

4.5.54 The reactor building incorporates a steel liner which forms the inner shell of the building. Sections of the liner would be pre-fabricated on-site inside a purpose-built temporary building and then transported to the reactor building where they would be craned into position before being welded to the other liner sections.

4.5.55 The reactor building is pre-stressed using steel tendons to improve its strength. During construction, tendon ducts are incorporated within the concrete walls of the building and the tendons are then threaded through the ducts and tensioned in a controlled manner before being anchored. The tendon ducts are then filled with grout.

4.5.56 As the buildings are constructed, the surrounding excavations are backfilled until a level is reached just below the final ground level. The final surfacing would be undertaken at the end of construction as part of the on-site landscaping.

ii. Conventional Island

4.5.57 The conventional island contains a combination of reinforced concrete and steel-framed buildings. The concrete buildings would be constructed using similar methods to the nuclear island buildings. The steel-framed buildings would be erected using pre-fabricated steel sections lifted into place using mobile cranes. Secondary steel sections would be attached to the main frame to allow cladding to be attached to make the building weather-tight. Most of the steel sections would be fabricated off-site and bolted or welded together in-situ, although some pre-fabrication may be carried out on-site.

iii. Cooling Water Infrastructure

4.5.58 The cooling water system draws water from the Bridgwater Bay and passes it through the turbine condensers and plant coolers before returning it to the bay. The




water intake structures are positioned approximately 3.3 km offshore and the outfall approximately 1.8 km offshore. The intake and outfall are connected to the power station cooling water pumphouse by tunnels which are lined with concrete and the connections from the cooling water pumphouse to the turbine condensers are by means of buried composite steel/concrete pipes.

4.5.59 The cooling water tunnels would be bored from deep onshore excavations using tunnel boring machines. The tunnels would be lined with pre-cast concrete sections as they are bored. The excavated material would be transported back to the tunnel entrance where any bentonite used in the tunnel boring process is recovered for re-use before the rock is transported to the appropriate stockpile for use in the final land re-profiling and landscaping. Tunnelling is likely to take place as a continuous activity for several days and nights at a time. Whilst excavated material would be transported to the stockpile during the day and night, distribution and grading of the material would be restricted to the daytime in order to keep night-time noise levels within acceptable limits.

4.5.60 Connections to the intake and outfall structures are made via lined vertical shafts which are bored from the seabed down to the tunnels. The shafts would be bored using wet drilling techniques, and would be undertaken from a jack-up rig. The intake and outfall structures would be prefabricated and floated into position over the connecting shafts before being lowered into position.

4.5.61 The fish return tunnel for the Fish Recovery and Return (FRR) system would be tunnelled under the foreshore using a directional drilling technique.

iv. Ancillary Buildings

4.5.62 The proposed ancillary buildings would be predominantly steel-framed although some reinforced concrete is used. Construction activities for the ancillary buildings would generally be similar to the conventional island buildings.

v. Construction of the National Grid 400kV Substation

4.5.63 Construction of the National Grid substation would be a separate activity, undertaken by National Grid and its contractors. In addition to the substation, National Grid would divert some of the existing overhead lines in the vicinity of the site to serve the new substation. They would also provide a new overhead line connection to the existing Hinkley Point B 400kV substation.

4.5.64 The substation compound includes a building which would house the gas insulated switchgear, an amenity building, workshop buildings and a diesel generator building. In addition, there would be three single phase series inductor tanks, which would be brought by sea to Combwich Wharf and then by road to site.

vi. Construction of the Emergency Access Road and the Bridge Over Bum Brook

4.5.65 The emergency access road provides an access route to the site for emergency vehicles, which is independent of the main site access. It would run from a junction with the road running through Shurton to the power station outage access gate, via the road connecting Wick Moor Drove to the southern power station car park.




4.5.66 The emergency access road would not normally be used and there would be a locked gate at the junction in Shurton. The road would be single-track with passing places and incorporate a bridge over Bum Brook. The bridge would be single lane and designed to keep the road above the maximum flood level of Bum Brook whilst minimising the restriction to floodwater flows. It would also incorporate a footway to provide pedestrian access to the landscaped areas at the south of the site.

4.5.67 The emergency access road junction in Shurton would be designed to incorporate provision for adequate visibility splays and turning circles for emergency service vehicles. This would necessitate the removal of a length of existing hedge in order to achieve acceptable sight lines. New hedges would be planted as part of the landscaping scheme and a pedestrian gate would be provided alongside the locked vehicle gate to facilitate pedestrian access.

4.5.68 Construction of the road to the south of the bridge and the southern part of the bridge would be undertaken using access from Shurton, as access from the north would be limited by the existing bridge capacity. Construction access for the northern part of the bridge and the remainder of the access road would be from the north.

4.5.69 The detailed design of the bridge would take account of the flood risk assessment findings. It would probably incorporate pre-cast concrete sections and may require piling for the foundations. It is envisaged that the piling would utilise cast-in-situ piles using pre-drilled holes to minimise noise and disturbance.

4.5.70 The southern part of the emergency access road, including the junction in Shurton and the bridge over Bum Brook, would be constructed shortly after the DCO is granted as part of the early landscaping of the area south of grid line 144750mN. The northern part of the road would initially be temporary and connect to the construction road network, although it would only be used as an alternative access for emergency vehicles. Once construction of HPC is complete and the accommodation campus buildings have been removed, a revised temporary route would be established through the site of the campus so that the final landscaping can be implemented and the final road alignment can be established across the landscaped area.

vii. Landscaping of the Southern Area

4.5.71 The land south of grid line 144750mN would not be used as part of the main construction site, although it would accommodate the emergency access road and its bridge over Bum Brook. The final landscaping proposals for this area involve raising the ground levels in the northern part of the area and new planting.

4.5.72 Planting along the southern part of this area would provide early screening of the main construction works. The areas that would not be remodelled as part of the final landscaping have been planted ahead of the start of the preliminary works, to provide initial screening.

4.5.73 In order to bring forward the final planting and increase the height of the screening of the construction works from the south, it is proposed to undertake the final re-modelling and landscaping of most of the area south of grid line 144750mN immediately following grant of DCO. This work is expected to take up to six months and would involve bringing material from the main site and stockpiles to increase the




height of the land. Construction of the southern part of the emergency access road and the bridge over Bum Brook would take place at the same time. Final landscaping and planting of this area would have time to develop and mature during the construction works.

viii. Utilities Infrastructure

4.5.74 During the site preparation works phase, new networks