definitions of elasticity

8/13/2019 Definitions of Elasticity

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NOT PROTECTIVELY MARKED

CONSTRUCTION METHOD STATEMENT


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CONTENTS

1. INTRODUCTION.............................................................................................................31.1 Purpose ...........................................................................................................................31.2 Related Documents.........................................................................................................42. STRATEGIC CONSTRUCTION PROGRAMME .............................................................52.1 Introduction......................................................................................................................52.2 HPC Project Construction Programme............................................................................63. ENABLING AND PRELIMINARY WORKS....................................................................113.1 Introduction....................................................................................................................113.2 Enabling Works .............................................................................................................113.3 Preliminary Works .........................................................................................................114. CONSTRUCTION OF HPC...........................................................................................174.1 Introduction....................................................................................................................174.2 Land Use .......................................................................................................................174.3

Temporary Buildings and Structures .............................................................................19

4.4 Construction Programme and Phasing..........................................................................224.5 Construction Activities ...................................................................................................254.6 Construction Logistics ...................................................................................................395. ROLE OF THE ASSOCIATED DEVELOPMENT SITES ............................................... 475.1 Introduction....................................................................................................................475.2 Individual Sites ..............................................................................................................476. CONSTRUCTION OF ASSOCIATED DEVELOPMENTS ............................................. 616.1 Introduction....................................................................................................................616.2 Temporary Buildings and Structures .............................................................................616.3 Individual Sites ..............................................................................................................617. HIGHWAY IMPROVEMENTS .......................................................................................758. CONSTRUCTION AND ENVIRONMENTAL MANAGEMENT.......................................778.1 Introduction....................................................................................................................778.2 Construction Management ............................................................................................778.3 Environmental Management during Construction..........................................................789. EMERGENCY ARRANGEMENTS ................................................................................819 1 Introduction 81


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

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

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

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

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

Figure 4.1: Hinkley Point C Indicative Construction Activities early 2013 Site Layout PlanRegulation 5(2)(O)

Figure 4.2: Hinkley Point C Indicative Construction Activities 2014 Site Layout Plan Regulation5(2)(O)

Figure 4.3: Hinkley Point C Indicative Construction Activities 2015 Site Layout Plan Regulation5(2)(O)

Figure 4.4: Hinkley Point C Indicative Construction Activities 2019 Site Layout Plan Regulation

5(2)(O)Figure 4.5: Hinkley Point C Indicative Construction Activities 2020 Site Layout Plan Regulation

5(2)(O)

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

Figure 4 7: Hinkley Point C Indicative Construction Activities Sections A A B B C C and D D


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1. INTRODUCTION

1.1 Purpose

1.1.1 This document, together with its appendices, describes the programme andmethodology for constructing Hinkley Point C (HPC), and supports the application tothe IPC for Development Consent as well as providing information for theEnvironmental 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 preliminaryworks 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 activitiesincluding proposed land used, construction machinery and site facilities.

1.1.5 Section 5describes the need for and role of each of the associated developmentsduring the construction of HPC, including the timing of the introduction of the facilitiesat these sites.

1.1.6 Section 6 describes the methodology for constructing and decommissioning each ofthe associated developments associated with HPC, including the accommodationcampuses, park and rides, freight management facilities, Cannington bypass andCombwich Wharf.

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

1.1.8Section 8

describes the construction and environmental management arrangementsthat would be employed to ensure comprehensive control of safety and protection ofthe environment.

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


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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 MonitoringPlans (Environmental Statement, Annex 3).

Off-Site Associated Developments Environmental Management and MonitoringPlans (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).


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2. STRATEGIC CONSTRUCTION

PROGRAMME2.1 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 balanceof plant, ancillary buildings and structures, the National Grid 400kV substation andEDF 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 areconsidered necessary to facilitate the construction, and in some instances, the

operation of HPC and to mitigate potential environmental impacts associated with theHPC Project. In the absence of the proposed associated developments, the likelytraffic and socio-economic impacts associated with the construction and operation ofHPC would be significantly greater in the local area. The proposed associateddevelopments include:

A d ti i B id t


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Refurbishment of the existing Combwich Wharf facility to accommodate the arrivalof approximately 180 Abnormal Indivisible Loads (AILs) and other constructionrelated 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 insections 5 and 6.

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

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

2.2 HPC Project Construction Programme

2.2.1 As illustrated in Plate 2.2, the HPC construction programme is anticipated tocommence with the site preparation works in late 2011, followed by the mainconstruction in early 2013, through the Development Consent Order granted by theIPC. 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 EPRreactor unit operational approximately 18 months later in 2020. However, completionof the spent fuel store would extend some two years beyond initial operation ofUnit 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 andprovide early screening of the construction works for the residents to the south of thedevelopment site. In addition, landscape screening would be provided along thewestern boundary of the development site.

2.2.3 The final landscape restoration works would commence once the construction phaseis complete and HPC is operational. Initially the temporary working areas would becleared, including the on-site accommodation campus, and then the HPC

Development Site would be landscaped which would take up to three years tocomplete.

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


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Construction Method Statement | October 2011 7


Plate 2.1: Hinkley Point C Developments Key Plan


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8 Construction Method Statement | October 2011


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


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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 secondUK EPR reactor unit becoming operational.

2.2.5 This schedule is based on the assumption that the temporary jetty would be grantedconsent and construction would commence mid 2012. The jetty would takeapproximately 14 months to construct, which includes a period for delays in theconstruction programme as a result of any adverse weather conditions (weatherrisk). 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 thisperiod 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 jettyconstruction would be undertaken in parallel with the main construction works.

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

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

Plate 2.3: Profile of Workforce Numbers Over Time


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2.2.9 The Accommodation Strategy addresses the capability of existing localaccommodation to house construction workers and defines the need for and size ofaccommodation 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 describedin Section 5.

2.2.10 The remaining workers would be distributed around the local area and thegeographical distribution is predicted using a gravity model in the TransportAssessment . This assessment has identified the need for park and ride facilities aspart of an integrated approach to worker transport and indicates the requiredcapacities 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 aregiven in the Freight Management Strategy. In conjunction with the TransportAssessment this document indicates the need for and scale of freight managementfacilities required at Junctions 23 and 24 of the M5 and the freight laydown facilityadjacent to Combwich Wharf as described in Section 5.

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


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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 areproposed 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 forthe 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 oftemporary 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 tobe demolished when the site is cleared. There are suspected bat roosts locatedwithin these barns and therefore a new bat barn is to be created to re-house them.

c) New Hinkley Point B Car Park3.2.4 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 isthe subject of a Certificate of Lawful Use or Development from West SomersetCouncil.

d) Trenching Works and Testing

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

3.3 Preliminary Works

3 3 1 T f ilit t th t ti f l t ti t HPC EDF E


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3.3.4 On the advice of the Marine Management Organisation, the proposed HarbourEmpowerment Order that would permit the construction and subsequent operation ofthe 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 tobe 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 worksare also included within the DCO application (as are the site preparation works). TheDCO application also includes for the dismantling and removal of the temporary jettyat the end of its operational lifespan.

3.3.6 If the jetty works application is not granted ahead of DCO, the HPC Project schedulewould 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 thetemporary jetty. Description documents from these stand-alone applications areprovided inAppendices A1 and A2 respectively. If both the site preparation worksand temporary jetty are consented, their work scopes would be integrated as far aspossible (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 andassociated facilities including welfare facilities and offices, layover facilities, carparks, 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, andsite clearance works including the diversion of rights-of-way, demolition of threeexisting barns; archaeological mitigation works and the removal of all of thewoodland 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 6mAOD centred on units 1 and 2 respectively. It is estimated that approximately 2.3million m3 (unbulked) of material would be excavated in total during the sitepreparation works and used for construction of the level platforms or stockpiledon-site for re-use. The proposed stockpile areas and stockpiling methodologiesare determined by the volumes and properties of the materials, requiring the


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creation of screening bunds and landscaped areas, using subsoil, overburdenand 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 ofthe 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 waterinto the existing open Holford Stream watercourse.

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

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

all surface water discharges meet appropriate water quality standards in termsof 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 eventoccurring during the construction period.

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

Dewatering of the working areas around the areas proposed for deeperexcavations during the main construction phase. Water collected from dewateringwould 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 gradelevel (this structure being subsumed by the sea wall within the HPC works).

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

a north south haulage road which would allow for the transfer of excavated


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Construction of site access points to the north-east of the site to provide the mainsite access during the site preparation works, with a second site access gate tothe 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 ofthese would be used for concrete for the preliminary works, the other would not beused for concrete production with the exception of concrete tests until theDevelopment Consent Order is granted.

b) Temporary Jetty3.3.9 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 tofacilitate 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 beinserted using either the drill and drive technique or into pre-drilled sockets

where they would be grouted into place. The onshore and foreshore piles wouldbe inserted using land-based equipment. The offshore piling would use a jack-upbarge;

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

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

Dredging of a berthing pocket alongside the jetty head to allow ships of up to5,000 deadweight tonnes (dwt) to berth;

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


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3.3.11 The project schedule envisages that the site preparation consent would be receivedfirst and the following activities, which are common to both applications, would beimplemented 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 accesscorridor running along the top of the foreshore between here and the jetty sitebeing 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 theeast-west service road between the onshore jetty site and the site entrance, asdescribed 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 terracingduring site preparation. The soil storage areas identified in the jetty application wouldalso not be needed because the soil strip would occur during site preparation and thesoils would be stored in the areas identified in the southern part of the HPCdevelopment 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 duringsite 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 sitepreparation works are also consented, because in this scenario all footpaths crossingthe HPC development site would be diverted onto an alternative route runningaround the perimeter of the site outside of the construction fence. The coast pathwould 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 safelyaccommodate the coast path running beneath it during the operational phase of thejetty.

3.3.15 The Site Preparation Works and Temporary Jetty descriptions (Appendices A1 andA2) include the removal and reinstatement activities to be undertaken in the event


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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 theHPC development site. The site comprises an area of land to the west of the existingHinkley Point A and Hinkley Point B power stations, between the village of Shurton tothe 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 trackwould be retained and protected for most of its length and two crossing points areprovided for construction traffic.

4.2.3 The southern limit for main construction activity has been set as OS grid line144750mN, to provide a buffer zone between the main construction activity and thevillage of Shurton. However, limited works (early landscaping and the construction ofan emergency access road and associated bridge over Bum Brook) would take placewithin 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 managementzone(s) would be integrated into a landscaped western boundary, which serves toreduce 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 importof bulk materials, primarily aggregate, sand and cement for concrete production andother construction materials.

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


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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 WickMoor Drove via a roundabout into the southern part of the site. This southern accessincorporates a waiting area and search lanes for delivery vehicles. Workers wouldmostly be bussed to site and arrive via the northern roundabout and a coach drop-offand parking area on the site of the southern permanent station car park. Workerswould 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 aseries of platforms and excavation of the main site would start. The total excavationand ground terracing works would involve the movement and storage ofapproximately four million m3 of material, of which about 2.3 million m3 would bemoved during the site preparation works. To avoid additional road journeys, all thematerial would be retained on site. This would necessitate the culverting of HolfordStream 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 storageareas for topsoil, re-usable excavated rock, weathered rock and overburden. Theareas for soil storage would be subdivided to segregate the various categories ofmaterial and allow multiple uses of the areas, where practicable. Topsoil storagerequires 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 forsome classes of fill. This rock, which is destined for engineered backfill, needs toremain accessible during storage. Other material, which would not be used forengineered backfill, would be stored in areas to produce level platforms suitable foraccommodating temporary contractors facilities.

4.2.11 Water management zones would be located in the north, east and west of the site tocontrol 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 thesouth of the southern construction area, to deal with run-off from the proposed earlylandscaped area. The northern water management zones would be removed as thepermanent site drainage systems are implemented.

4 2 12 Areas of the site that are not required for permanent plant and buildings would be


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4.2.14 The construction of the National Grid 400kV substation in the south-east corner of thepermanent power station area, along with the diversion of existing overhead lines tofacilitate connections to the National Grid transmission system would be undertaken

by National Grids contractors as a separate activity. A temporary working areawould be provided to the south and east of the substation for the duration of NationalGrids construction works.

4.2.15 Construction of the EDF Energy overhead transmission lines and towers on thepermanent 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 permanentdevelopment site. Within the development site boundary, the layout of the site wouldvary over the construction period but, taking this into account, the anticipatedprincipal uses of the overall land area within the development site at the peak phaseof construction, in 2016, are presented in Table 4.1below.

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 thedifferent stages of development activity. For example, the area allocated to the civilworks contractor would be reduced and the spare land reallocated to the mainmechanical and electrical contractors as the balance of work on the site changes.The changing usage of land is illustrated in Figures 4.1 to4.5.


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4.3.2 Whilst the heights of the permanent buildings at the HPC Development Site aredefined 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 theheight limits for various areas of the site.

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

Table 4.2: Construction Related Buildings and Structures: Height Parameters

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

1

Zone 1: Construction of themain nuclear island,conventional island, balance

of plant and ancillarybuildings.

Working envelope for main buildingconstruction requirements. Structures toinclude:

temporary buildings, construction warehousingand storage buildings; and

tower cranes, mobile cranes and otherspecialised lifting equipment.

140m AOD

Zone 2: Construction of themain nuclear island andconventional island Exceptional Structures

Working envelope for exceptional structuresthat are required for the lifting and installationof reactor domes and other time limitedactivities that require specialised cranes orlifting equipment that go above the heightparameters set out in Construction Zone 1.

Typically these would include large mobilecranes for installation of the dome associatedwith the two reactor units.

175m AOD

Zone 3: Contractor areas tothe north of green lane.

Working envelope for liner fabrication facilities,workshops, storage buildings, offices andmess facilities, concrete batching plants and

associated aggregates stockpiles, coveredstockpiles and cement/pulverised fuel ashsilos.

75m AOD

Zone 4: National Gridsubstation area.

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

80m AOD


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

1

Zone 6: On-siteaccommodation campus Working envelope for the onsiteaccommodation campus. 32m AOD

Zone 6: On-siteaccommodation campus Exceptional Structures

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

55m AOD

4.3.4 Exceptional structures comprise very large cranes and similar equipment whichwould 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 beremoved.

4.3.5 Other buildings and structures include temporary buildings which would be used bythe contractors for fabrication, storage, offices and welfare, as well as long-termcranes such as tower cranes. The height parameters for buildings and structuresalso 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 thewest which would be used by the main construction and erection contractors. Zone 2is within Zone 1 and includes the main nuclear island, conventional island buildingsand the areas immediately to the south and west where liner fabrication may beundertaken. Zone 2 is where very large mobile cranes would be used for installationof 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 cementbrought in by the jetty would be stored and construction/erection contractors wouldsite their storage and prefabrication facilities. Zone 3 also includes the area south ofZone 1 where the platform level is +20m AOD and various ancillary power stationbuildings would be constructed. It also includes an area for the main nuclear steamsupply 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 contractorswould be based. During the early construction works, this area may also be used bythe main civil works contractor for laydown and storage.


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4.3.14 The HPC Development Site would be enclosed by construction hoardings, securityfencing and perimeter enclosure, initially in the form and locations required for sitepreparation. 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 toenable the temporary construction-related development to be erected without theneed 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 thisprogramme. Following the site enabling and preliminary works, as described inSection 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 thesecond reactor unit would generally follow the first unit by 18 months. Temporaryconstruction infrastructure would be required to support each phase.

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

4.4.3 Figures 4.1 to 4.5and the associated descriptions are based on the enabling andpreliminary works described in Section 3 having been commenced on scheduleahead of DCO consent. In the event that any of the necessary permissions are notreceived prior to DCO consent, the respective works would be integrated into themain power station construction schedule as appropriate.



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The landscaping along the western site boundary would be substantiallycomplete.

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 beunder construction.

The main platform areas would have been established in the northern part of thesite 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 ofdrainage and the principal network of construction drains would be in place withan outfall to the sea shore.

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

4.4.5 Figure 4.2shows the indicative layout of the construction site at the start of nuclearisland 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 beenallocated 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 thesouthern 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-siteaccommodation campus area has been levelled and accommodation blocks andfacilities are in the final stages of construction.

The Public Information Centre and some permanent offices and ancillary buildingsd t ti


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the contractors areas would be cleared and temporary services removed;

temporary re-routing of the emergency access road would be established to allowthe 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 finalalignment of the emergency access road and the visitor access road to the southcar park.

4.5 Construction Activities

4.5.1 The construction would be undertaken by a number of contractors. The number ofcontract packages would be limited, which would maximise consistency in themanagement and control of site activities. Construction activities would be controlledby the use of construction method statements which would be prepared by thecontractor 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 andthe marine works and ancillary buildings contractors would mobilise. This would befollowed progressively by the mobilisation of the other site contractors. Mobilisationwould 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 undertakencovering 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 sitepreparation works contractor. Surface water drainage would be via the constructiondrainage systems installed during the site preparation works Service connections for



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would be constructed at the southern and northern site access points during the sitepreparation 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 beoffloaded at the temporary jetty. The jetty could also be used for the import of otherbulk materials to the site, where this is practicable.

4.5.7 Other construction materials would be delivered by road and would enter the site viathe southern roundabout. As detailed in the Freight Management Strategy, all roaddeliveries would be managed using a computerised delivery management system

which controls the timing of deliveries. Vehicles arriving via the motorway networkswould be required to check-in at one of the freight management facilities at J23 orJ24 and would be despatched to site in accordance with a strict timetable. Deliveryvehicles would be subject to search in line with the security policy before entry andwhen leaving the site. Deliveries would normally be made to the respective sitecontractors 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 bedelivered 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 transporteddirectly to the point of installation via the northern roundabout. All such deliverieswould 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 inaccordance with the Waste Management Implementation Strategy. Wherepracticable, sea transport would be used, but most transport would be by road. Thedelivery management system would be used to manage the timing of freight vehicles,including empty vehicles, leaving the site to ensure compliance with the transportplan for waste and materials movements.

4.5.10 In accordance with the Framework Travel Plan, nearly all personnel working at theconstruction 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 takethem via the northern roundabout to the site personnel entrance adjacent to thesouth permanent station car park. This car park would be dedicated to buses for theduration of the construction period, although the access route would vary accordingto the stage of construction works. Workers would enter the site through turnstilesadjacent to the bus drop-off point and would be subject to security controls and



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their responsibilities for health and safety and worker welfare. In addition, therewould be 100 car parking spaces allocated for visitors, including VIP visitors to thesite, disabled visitors to the Public Information Centre (PIC) and coach parking for

other PIC visitors. Provision for pedal cyclists would be made at the constructionsite, 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 thesite via dedicated turnstiles adjacent to the campus. All other persons who do notwalk or cycle to site and are not entitled to the use of one of the limited car parkspaces would be required to use the bus service to the site, via the park and ridesites if necessary.

d) Internal Haulage Roads

4.5.14 During the site preparation works, a number of haulage roads would be developed onsite to facilitate the movement of vehicles carrying excavation and constructionmaterials around the site. These haulage roads are indicated on Figures 4.1 to 4.5and would vary in location and level according to the construction needs. Wherepracticable, 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 ofthe site within the security fence, to allow security and maintenance personnelaccess to inspect and maintain the fence line.

4.5.16 The haulage roads would be constructed in accordance with the current relevantBritish Standards and the Highways Agency Design Manual as required for heavyvehicle usage and estimated traffic volumes. These haulage roads would be

surfaced with tarmac or compacted granular material as appropriate, and the surfacewater drainage would be tied into the construction drainage systems to be installedduring the site preparation works.

4.5.17 Lighting would be provided along the haulage roads in line with the ConstructionLighting StrategyinAppendix A3.

e) Civil Works

i. Introduction

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



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

4.5.21 Excavations for Unit 2 would continue after the excavations for Unit 1 are completeand construction of the Unit 1 buildings is underway. Excavations for the interimspent fuel store would take place during the latter stages of Unit 1 construction, oncethe 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 itwould be placed and levelled to produce a temporary working platform to the eastand levelled storage areas to the west.

4.5.23 Backfilling of the excavations as the buildings are constructed would be managed inaccordance with the engineering performance required. Different material standardsare applied depending on the location of the backfill. Where practicable, excavatedmaterial 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 sizestandards required for backfill, rock crushing plant would be used. Where excavatedmaterial is insufficient or unsuitable for backfill, appropriate granular fill materialwould be imported.

f) Construct ion 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 frontof the permanent power station site and would incorporate return sections at eachend of the wall to prevent erosion from the side. A 30m wide corridor from the cliffline 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 worksand 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. Accesssteps would be provided at intervals along the length of the wall to allow safe accessand egress from the foreshore level.

4.5.26 The construction methodology for the sea wall would be the responsibility of the



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

4.5.31 The main wall section would be cast within prepared formwork, prior to installation ofthe drainage works behind the wall and partial backfilling behind the wall. Theconstruction 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 beinstalled 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 andreinforced concrete cladding on the passive side. Pedestrian access ramps would beformed to carry the footpath over the return walls and link into the existing sections ofthe West Somerset Coast Path.

4.5.35 Once the construction drainage system has been decommissioned, the associatedoutfall 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 upto 510 workers in accordance with theAccommodation 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



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

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

Construction Works

4.5.42 The construction works would commence with the preparation of the platform andrequired 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 beundertaken. 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 becompleted as one of the last works before occupation.

4.5.44 The section of road providing access to the site would be completed undersupervision of the highway authority. The permanent entrance into the site, off theC182, would be constructed.

4.5.45 The surface water drainage, as well as foul and surface water connections, would beinstalled 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 amodular construction is used, would be delivered to the site on flat-bed vehicles, thenlifted into position by mobile cranes and connected together. Where on-site steelframed construction is to be utilised, this would be assembled and fitted out with theinternal mechanical and electrical services installed. The utility connections wouldthen 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 theperimeter of the site.

Operation and Decommissioning


Plate 4.1: HPC Accommodation Campus


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h) Construction of Bui ldings and Infrastructure

i. Nuclear Island

4.5.52 The nuclear island buildings are constructed of reinforced concrete. The concretewould be mixed on site using a batching plant and would use sand, aggregate andcement imported via the temporary jetty. In some cases, cement substitutes, such aspulverised fuel ash would be used to secure specific concrete properties. Thereinforcement would be with steel reinforcing bars, fabricated into cages appropriateto the building geometry and strength requirements. Some reinforcement would beprefabricated into assemblies which can be lifted into place. Such pre-fabricationwould 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 insuch a way that they are able to transmit the loads of the attached equipment into theconcrete.

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

4.5.54 The reactor building incorporates a steel liner which forms the inner shell of thebuilding. Sections of the liner would be pre-fabricated on-site inside a purpose-builttemporary building and then transported to the reactor building where they would becraned 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 thebuilding and the tendons are then threaded through the ducts and tensioned in acontrolled manner before being anchored. The tendon ducts are then filled withgrout.

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 beundertaken 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-



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

4.5.59 The cooling water tunnels would be bored from deep onshore excavations usingtunnel boring machines. The tunnels would be lined with pre-cast concrete sectionsas they are bored. The excavated material would be transported back to the tunnelentrance 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 activityfor several days and nights at a time. Whilst excavated material would betransported to the stockpile during the day and night, distribution and grading of thematerial would be restricted to the daytime in order to keep night-time noise levelswithin acceptable limits.

4.5.60 Connections to the intake and outfall structures are made via lined vertical shaftswhich 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 intakeand outfall structures would be prefabricated and floated into position over theconnecting shafts before being lowered into position.

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

iv. Ancillary Buildings

4.5.62 The proposed ancillary buildings would be predominantly steel-framed althoughsome reinforced concrete is used. Construction activities for the ancillary buildingswould 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 Gridwould divert some of the existing overhead lines in the vicinity of the site to serve thenew substation. They would also provide a new overhead line connection to theexisting Hinkley Point B 400kV substation.

4 5 64 The substation compound includes a building which would house the gas insulated



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4.5.66 The emergency access road would not normally be used and there would be alocked gate at the junction in Shurton. The road would be single-track with passingplaces and incorporate a bridge over Bum Brook. The bridge would be single laneand designed to keep the road above the maximum flood level of Bum Brook whilstminimising the restriction to floodwater flows. It would also incorporate a footway toprovide 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 incorporateprovision for adequate visibility splays and turning circles for emergency servicevehicles. This would necessitate the removal of a length of existing hedge in order toachieve acceptable sight lines. New hedges would be planted as part of the

landscaping scheme and a pedestrian gate would be provided alongside the lockedvehicle gate to facilitate pedestrian access.

4.5.68 Construction of the road to the south of the bridge and the southern part of the bridgewould be undertaken using access from Shurton, as access from the north would belimited by the existing bridge capacity. Construction access for the northern part ofthe 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 assessmentfindings. It would probably incorporate pre-cast concrete sections and may requirepiling for the foundations. It is envisaged that the piling would utilise cast-in-situ pilesusing pre-drilled holes to minimise noise and disturbance.

4.5.70 The southern part of the emergency access road, including the junction in Shurtonand the bridge over Bum Brook, would be constructed shortly after the DCO isgranted 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 theconstruction road network, although it would only be used as an alternative accessfor emergency vehicles. Once construction of HPC is complete and theaccommodation campus buildings have been removed, a revised temporary routewould be established through the site of the campus so that the final landscaping canbe implemented and the final road alignment can be established across thelandscaped 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 mainconstruction site, although it would accommodate the emergency access road and itsbridge over Bum Brook. The final landscaping proposals for this area involve raising



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

viii. Utili ties Infrastructure

4.5.74 During the site preparation works phase, new networks of utilities would be installedwhich would provide for the main construction works and there would be asubsequent transition to the utilities for the operating power station.

Electrical Infrastructure

4.5.75 Electrical power would be provided for the construction works by means of adedicated supply from the existing Hinkley Point Power Station Complex with a newtemporary distribution network serving the whole of the construction site. Extensivesub-metering would be installed to monitor construction electricity usage.

4.5.76 Once the new National Grid 400kV substation is complete and connected to thenational grid high voltage electricity transmission system, supplies for the

energisation of the permanent power station plant would be made available, prior tothe main electricity generator connections being made. All the permanent buildingson the site would ultimately be fed directly from the operating HPC power station.The temporary electrical systems would be decommissioned as the construction areais cleared and the supply from the existing power stations would be terminated.

4.5.77 HPC would be connected to the national grid high voltage electricity transmission via,two double circuit overhead lines which currently connect the existing Hinkley Point A

and B power stations. These circuits would be diverted to the new National Grid400kV substation and in addition, a new double circuit overhead line would also bebuilt to connect to the existing National Grid Hinkley Point B 400kV substation. Thetransmission system connection works would be undertaken by National Grid under aseparate application for development consent by National Grid to the IPC (or itssuccessor).

Lighting

4.5.78 Lighting of the main construction area and access and haulage roads on theconstruction site would be provided by EDF Energy or its contractors. The lightingdesign would comply with the Construction Lighting Strategy. The principalmeasures of this strategy are:



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4.5.79 Lighting of the contractors compounds would be the responsibility of the individualcontractors, but EDF Energy would require such lighting to comply with theConstruction Lighting Strategyand achieve the objectives indicated above.

Water Supplies

4.5.80 A new water supply main is planned to serve the HPC site and this would be installedby the local water company. The new main would enter the site from the east near tothe northern roundabout and would be installed underground. This supply wouldserve both the construction works and the permanent power station via temporaryand permanent distribution networks with metering to monitor usage. The temporarynetwork would be decommissioned as the construction site is cleared at the end of

the construction works.

Drainage Systems

4.5.81 A temporary construction drainage system would be constructed as part of the sitepreparation works. This drainage system would handle surface water run-off fromthe construction areas, groundwater pumped from the dewatering wells, sewageeffluent which would have received tertiary treatment, water pumped from the cooling

water tunnelling works and flushing water discharged during early commissioningworks. These discharges would be directed via water management zones to theappropriate discharge point.

4.5.82 The construction drainage system would be divided into three areas corresponding tothe current drainage zones. The northern area drainage would be directed to theforeshore of Bridgwater Bay, via a discharge outfall located to ensure the potential

impact on the intertidal environment is minimised. The southern construction areawould be drained to Holford Stream, as at present. As Holford Stream would beculverted for most of its length within the construction site, there would be twodischarge points via water management zones at the western and eastern edges ofthe site. The area to the south of Grid line 144750mN, which is the approximatealignment of the existing watershed, would be drained to Bum Brook. The need forengineered drainage of this area would be assessed as part of the earthworks designprocess and, if appropriate, a water management zone would be established to

control the flow into Bum Brook.

4.5.83 The construction drainage systems would be designed to cater for rainfallcorresponding to that expected from a one in 30 years event in accordance with bestpractice guidance, but would be assessed for its capability to cope with more extreme

i f ll


i t il ti d t t t f iliti i d P t f th t


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incorporate oil separation and treatment facilities as required. Parts of the temporaryconstruction drainage system would be incorporated into the permanent drainagesystems and this transition would take place during the later stages of construction.Remaining parts of the temporary drainage system within the permanentdevelopment would be removed or isolated and left in place.

4.5.86 The construction drainage systems located outside the permanent power stationfootprint would be removed as part of the construction area clearance. However theHolford Stream culvert would be retained as part of the permanent landscaping.

4.5.87 The permanent drainage systems would be designed to cater for rainfall levelsexpected to occur at a frequency of once in 100 years. In addition, the systemswould be designed to cope with extreme rainfall which is only expected to occur oncein 10,000 years, without allowing flood-water build-up on-site which could threaten toflood safety-related buildings.

4.5.88 The permanent drainage systems would include a groundwater drainage system,designed to maintain groundwater levels no higher than about six metres below thestation ground level, in order to limit the flotation forces on deep buildings. This

drainage system would discharge into the station cooling water system.

Sewage

4.5.89 A new sewage collection network would be installed for the construction site and thiswould take the sewage to a number of modular sewage treatment plants and thetreated water would be discharged into the site drainage systems. The temporaryplants would provide tertiary treatment to ensure acceptable discharge quality.

4.5.90 A new permanent sewage treatment plant would be built as part of the permanentpower station and this would service the permanent works, discharging treatedeffluent into the station cooling water discharge to the Bridgwater Bay.

ix. Site Offices and Welfare Facil ities

4.5.91 The site offices, canteens and other infrastructure would be subject to continuous

change as the workforce numbers change, the nature of the work evolves from civilconstruction, through mechanical and electrical installation, to commissioning andoperation, and as contractors arrive and depart from the site.

4.5.92 EDF Energy would exercise overall control of the temporary infrastructure within theconstruction areas and would allocate temporary compounds for contractors within


Mechanical and Electrical Works


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x. Mechanical and Electrical Works

4.5.95 The mechanical and electrical plant installation phase would commence when thecivil structures are sufficiently advanced to enable access. This would be in

approximately 2014. There would be a limited number of mechanical and electricalcontractors and they would install equipment manufactured by others, as well asequipment supplied under their own contracts.

4.5.96 The majority of the mechanical and electrical activity would take place within thepower station buildings in the north of the site. However, some of the contractorscompounds would be located in the southern part of the site. A significant proportionof the piping and ventilation ductwork would be pre-fabricated before installation,

either at the manufacturers works or on-site.

4.5.97 Most of the mechanical and electrical equipment would be delivered by road,although some items, such as small bore pipework, cable, and items manufacturedabroad, may be suitable for sea delivery. Suppliers would be encouraged to use seatransport where practicable.

4.5.98 Approximately 180 mechanical and electrical plant items, such as the reactorpressure vessels, would be very large and/or heavy and would require specialtransport to site. These are classified as Abnormal Indivisible Loads (AILs) andwould be shipped to Combwich Wharf by sea and then taken to site by road usingspecial trailers. These items would be taken straight to their final location andinstalled using special lifting and handling equipment.

4.6 Construction Logistics

4.6.1 This Section outlines the management of the flow of people and materials within theHPC development site.

a) Freight and Materials

i. Materials Quantities

4.6.2 HPC and the on-site associated development construction works would requirearound 5.1 million tonnes of material to be brought onto the development site, ofwhich at least 2.3 million tonnes is expected to be transported by sea via thetemporary jetty. The remaining 2.8 million tonnes would be transported by road. Adetailed schedule of material quantities is provided within the Freight ManagementStrategy


4 6 4 Other bulk materials arriving at the jetty would be offloaded by mobile crane and


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4.6.4 Other bulk materials arriving at the jetty would be offloaded by mobile crane andtransported by truck to the appropriate storage areas.

4.6.5 Most materials arriving by road would enter the site via the south entrance where

security checks would be carried out before the materials are trucked to theappropriate storage areas.

4.6.6 Road deliveries would be controlled via a delivery management system as describedin the Freight Management Strategy, in order to limit the impact on the roadnetwork.

4.6.7 Materials would be stored in the contractors compounds until required for installation.

4.6.8 Abnormal Indivisible Loads (AILs), which have been brought by sea to CombwichWharf, would be transported to site by road and would enter the site via the northernroundabout. Prior to being required at site, these loads would be stored at theCombwich freight laydown facility. The loads would then be taken direct to the pointof installation and would not be stored in the contractors compounds.

iii. Pre-fabrication

4.6.9 Materials delivered to site may be pre-fabricated into larger assemblies beforeinstallation. Examples of likely pre-fabrication are the reactor building steel liner andreinforcing bars for the reactor building structures.

4.6.10 Pre-fabrication of the reactor building steel liner would take place in a largetemporary building where welding can be carried out in a controlled environment.The pre-fabricated sections would be transported using large trailers along a heavyload route to the point where they can be lifted into place with a large jib crane.

4.6.11 Reinforcing bar cages could also be pre-assembled, the largest cages beingassembled close to the point of use, where they can be lifted directly into position bycrane. Smaller pre-assemblies could be fabricated further away and brought to thecrane by truck.

4.6.12 Other materials may be pre-fabricated within the contractors compound before beingtaken to the point of installation.

iv. Materials Handling

4.6.13 Unloading and loading of trucks within the contractors compounds would normally be


v Security


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v. Security

4.6.16 All vehicles entering and leaving the site would be subject to security checks in linewith the security plan.

b) Construction Workforce

i. Workforce Numbers

4.6.17 Workforce numbers have been estimated based on the workforce deployed to date atFlamanville 3, the first EDF EPR to be constructed, and the total estimated man-hours required to complete it. Experience of construction of multiple-unit plants inFrance has then been factored in to convert the single-unit Flamanville workforcenumbers into the workforce numbers required for the twin-unit power station at HPC.The approximate profile of workforce numbers is given in Plate 4.2

Plate 4.2: Workforce Profile

4 6 18 The peak workforce required at HPC is estimated to be around 5 600 with civil


the main construction site in the north Designated walkways would be provided to


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the main construction site in the north. Designated walkways would be provided toreduce potential conflict between pedestrian and vehicular traffic on the site.

iii. Working Hours

4.6.20 The working patterns of particular groups of workers would be determined by theneeds of the construction phase. Security staff would work shifts to cover the full 24-hour period with higher numbers on duty at times of workforce shift changeover andpeak material deliveries. Similarly, catering and cleaning staff would not necessarilywork the same shift patterns as other staff. Most office workers would work a normalday shift.

4.6.21 In addition, there will be other activities which require continuity of working, such astunnelling and large concrete pours, where the working pattern may differ from thosedescribed below. It is anticipated that this will involve a small proportion of theworkforce.

4.6.22 The majority of the workforce would work a double day shift with a small night shift.The workforce deployed on non-critical buildings would likely work a single day shiftand office workers would work a normal day pattern. The likely numbers of workersfor each of the shifts at the time of peak workforce numbers on site are given inTable 4.3below:

Table 4.3: Approximate Distribution of Workers between Shifts

Shift Number of Workers

Double Day Shift First shift 1,480

Double Day Shift Second shift 1,440Night shift 380

Single Day Shift 1,460

Office personnel 840

Total 5,600

4.6.23 The start times for each shift would vary within a range chosen to minimisecongestion and noise during the travel to and from work. The start and finish timesfor the various shifts from Monday to Friday is shown in Table 4.4below:

Table 4.4: Shift start/finish times Monday to Friday


4.6.24 For weekend working, two work patterns would be used. The first involves a single


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4.6.24 For weekend working, two work patterns would be used. The first involves a singleSaturday morning shift with no shift on a Sunday. The Saturday morning shift timesare shown in Table 4.5below:

Table 4.5: Shift start/finish times Saturday Morning

Shift Start Time Finish Time

Saturday Morning Shift From 06:00 to 08:00 From 13:00 to 15:00

4.6.25 The second weekend working pattern operates on a four-week cycle comprising 12working days (Monday to Sunday plus Monday to Friday) followed by a two-day non-working weekend (Saturday and Sunday) followed by 11 working days (Monday toSunday plus Monday to Thursday) followed by a three-day non-working weekend(Friday to Sunday). For this working pattern, the shift working times would be asTable 4.6below for all working days, including working weekends.

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

Shift Start Time Finish Time

Double Day Shift First shift From 06:00 to 07:30 From 14:00 to 16:00 or

after 17:30

Double Day Shift Second shift From 13:30 to 15:00 From 22:00 to 24:00

Night shift From 20:30 to 22:00 From 06:00 to 08:00

Single Day Shift From 07:00 to 08:30 From 16:30 to 18:30

4.6.26 Whichever weekend working pattern is followed, there would also be a limited

number of people (less than 300) working on the non-working days carrying outmaintenance and other activities similar to the night shift.

4.6.27 The night shift would generally be a maintenance and logistics support shift involvingrelatively quiet activities such as:

pre-placement of materials for the subsequent shifts;

repositioning of scaffolding; essential plant maintenance and repair;

dewatering operations;

refuelling;

l di ti iti t th j tt d


spreading and grading of such excavated material would be restricted to the


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p g g gdaytime.

4.6.29 The majority of night-time working would take place in the northern part of the site.

c) Site Access and Security

4.6.30 Workers would access the site via turnstiles operated by their identity passes. Theywould be subject to searches in accordance with the site security plan as they enterand leave the site. The main personnel access is in the northern part of the sitewhere the buses set down and pick up. Additional access turnstiles would beprovided at the south entrance for freight vehicle drivers and workers staying at the

on-site campus.

d) Site Offices and Welfare Facilit ies

4.6.31 EDF Energy would provide office space and welfare facilities for its own staff and forcontractors who do not require their own site compounds. EDF Energy would alsoprovide canteens, first aid and welfare facilities in the main construction area to thenorth of the HPC Development Site for use by all workers, in order to reduce walking

time to and from breaks etc. It is currently envisaged that there would be twocanteens and multiple welfare and first aid buildings within the main constructionarea. The welfare and first aid facilities would be relocated as necessary as the workproceeds.

4.6.32 In addition to the EDF Energy facilities, each construction contractor would berequired to provide office, changing and welfare facilities for their own staff withintheir allocated compounds. The contractors would also incorporate pre-fabrication

facilities, workshops and storage facilities, as necessary for their work, within theircompounds.

4.6.33 The medical centre would provide a 24-hour service. In addition to the treatment ofminor injuries and ailments, the medical centre would provide preventative healthcare. In the event of any serious injuries, the on-site medical team would provide firstaid and the local emergency services would be called to take any casualties to

hospital.4.6.34 Drug and alcohol testing would be carried out in accordance with the site policies on

workers entering the site. Smoking would not be permitted on-site except withinclearly designated smoking areas.


a site waste management contractor, who would receive the construction waste from


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the various construction and erection contractors and take the accumulated waste toappropriate sorting and recycling facilities. Further details on the management ofwaste arising from the HPC Project are provided in the Waste Management

Implementation Strategy.

f) Landscaping

4.6.38 The final hard landscaping of the built development would utilise materials broughtonto the site for this purpose. Depending on the quantities involved and theoriginating location, the jetty may be used to import these materials

4.6.39 The landscaping of the temporary working areas would utilise the materialsexcavated during the site preparation and excavation works. This material would berelocated using dump trucks and graders to form the final topography and topsoilwould be taken from storage to cover the area.

4.6.40 It is anticipated that the re-profiling would take place in phases. The north-westernand south-eastern areas of the site of the site would be built up using material fromthe stockpiles before surfacing with topsoil and seeding with meadow grass. Themain stoc