NOT PROTECTIVELY MARKED NNB-308-REP-000710 Version 2.0 NNB GENERATION COMPANY (HPC) LIMITED HINKLEY POINT C PROJECT CASE FOR REMOVAL OF THE REQUIREMENT TO INSTALL AN ACOUSTIC FISH DETERRENT Summary of the Engineering Optioneering Process NNB Generation Company (HPC) Limited Registered in England and Wales. Registered No. 6937084 Registered Office: 90 Whitfield Page 1 of Street, London, W1T4EZ Template No. NNB-301-TEM-000761 NOT PROTECTIVELY MARKED NOT PROTECTIVELY MARKED NNB-308-REP-000710 Version 2.0 APPROVAL SIGN-OFF: Name: Emma Beagley Originated by: Date: 06/07/18 Title: Marine Specialist Name: Ross Pettigrew Reviewed by: Date: 11/01/19 Title: Environmental Technical Manager (Non-Radiological) Name: Chris Fayers Approved by: Date: 11/01/19 Title: Head of Environment DOCUMENT CONTROL Version Purpose Amendment By Date 0.1 For Review Document issued as Final Draft RP 06/07/18 1.0 1st issue Document first issue following regulator review RP 11/01/19 For Document updated to address legal review 2.0 RP 11/02/19 submission comments NNB Generation Company (HPC) Limited Registered in England and Wales. Registered No. 6937084 Registered Office: 90 Whitfield Page 2 of 100 Street, London, W1T 4EZ Template No. NNB-301-TEM-000761 NOT PROTECTIVELY MARKED NOT PROTECTIVELY MARKED NNB-308-REP-000710 Version 2.0 CONTENTS 1 INTRODUCTION ............................................................................................................... 11 1.1 Hinkley Point C Nuclear Power Station ..................................................................................... 11 1.2 Purpose of this report ................................................................................................................ 11 2 BACKGROUND TO THE HPC COOLING WATER SYSTEM .......................................... 12 2.1 Introduction ................................................................................................................................ 12 2.2 Selection of cooling option......................................................................................................... 12 2.3 Components of the HPC cooling water system ......................................................................... 12 2.4 Location of the intakes .............................................................................................................. 14 2.5 Intake heads .............................................................................................................................. 16 3 APPROACH TO THE DETAILED AFD ENGINEERING PROCESS ................................ 19 3.1 Introduction ................................................................................................................................ 19 3.2 The AFD design and optioneering team .................................................................................... 19 3.3 Detailed design timeframe ......................................................................................................... 20 4 ESTABLISHING THE DESIGN AND FUNCTIONAL REQUIREMENTS FOR THE HPC AFD SYSTEM .......................................................................................................................... 21 4.1 Background to requirements and best practice ......................................................................... 21 4.2 Site specific constraints ............................................................................................................. 22 4.3 Transposition into finalised HPC works information .................................................................. 25 4.4 Lessons learnt from other sites using AFD technology ............................................................. 32 4.5 NNB requirements for an AFD system ...................................................................................... 38 5 ENGINEERING OPTIONEERING PROCESS .................................................................. 40 5.1 Introduction ................................................................................................................................ 40 5.2 SP location for acoustic field generation ................................................................................... 40 5.3 AFD mounting structures ........................................................................................................... 46 5.4 Electrical power supply and communications ............................................................................ 58 5.5 Power supply shore crossing ..................................................................................................... 61 5.6 Further design development ...................................................................................................... 62 5.7 Conclusions of the engineering optioneering process ............................................................... 66 6 CONCLUSIONS OF THE AFD DESIGN PROCESS ........................................................ 68 7 AFD MAINTAINENCE ....................................................................................................... 70 7.1 Overview ................................................................................................................................... 70 7.2 Description of main maintenance activities ............................................................................... 70 NNB Generation Company (HPC) Limited Registered in England and Wales. Registered No. 6937084 Registered Office: 90 Whitfield Page 3 of 100 Street, London, W1T 4EZ Template No. NNB-301-TEM-000761 NOT PROTECTIVELY MARKED NOT PROTECTIVELY MARKED NNB-308-REP-000710 Version 2.0 7.3 Maintenance and testing of the offshore monopile central hub and equipment ........................ 71 7.4 SP Maintenance ........................................................................................................................ 72 7.5 Conclusions on AFD maintenance ............................................................................................ 94 8 REFERENCES ..................................................................................................................98 APPENDIX A SAFETY AUDIT REPORT - OH2231-HPC-NNBGEN-XX-000-REP- 100000 ....................................................................................................................100 TABLE OF FIGURES Figure 2.1 Locations of the intake headworks and intake tunnels (also showing outfall headworks and tunnels and Fish Return System (HCF) tunnel and outfall)............................ 17 Figure 3.1 Key phases of the AFD engineering process ................................................... 20 Figure 4.1 Tidal states relative to the seabed and intake heads. ...................................... 24 Figure 4.2 Example of AFD SP (left) and ‘airbag’ (right) .................................................. 30 Figure 4.3 Aerial photograph of DOEL NPP on the Scheldt Estuary near Antwerp, Belgium, showing location of the water intake structures ....................................................... 33 Figure 4.4 Diagram showing the SP mounting units at Doel and the remote retrieval mechanism ......................................................................................................................... 34 Figure 4.5 Aerial view of Pembroke CCGT ...................................................................... 35 Figure 4.6 Diagram showing the location of the SPs at Pembroke being raised / lowered .. ......................................................................................................................... 36 Figure 5.1 Deflection Principle 1 – SPs mounted at the end of intakes ............................ 41 Figure 5.2 Deflection Principle 2 – SPs mounted along the sides of the intake ............... 41 Figure 5.3 Sound modelling results for SP clusters at either end of the intake head. The sound field is shown in red – yellow and the intake head in grey. ........................................... 43 Figure 5.4 Sound modelling results for SP line array at either end of the intake head. The sound field is shown in red- yellow and the intake head in grey. ............................................ 44 Figure 5.6 Sound modelling results for 8 m SP offset. The sound field is shown in red- yellow and the intake head in grey .......................................................................................... 45 Figure 5.7 Depiction of SPs suspended from subsea buoy. ............................................ 48 Figure 5.8 Depiction of SPs suspended from surface buoy. ............................................ 49 Figure 5.9 Depiction of SPs on articulated arms. ............................................................. 50 Figure 5.10 Depiction of the tie-bars cast into the intake head and the SP fixing. ............. 50 Figure 5.11 Depiction of barge supported SPs .................................................................. 51 Figure 5.12 Depiction of SPs incorporated in the nose of the intake head ......................... 52 Figure 5.14 Depiction of SPs mounted on subsea gravity base ......................................... 53 Figure 5.15 Depiction of SPs mounted on subsea beam structure anchored to the intake head foundation chamber ....................................................................................................... 54 Figure 5.16 Depiction of SPs mounted on discrete subsea structures supported by posts cast into the intake head foundation chamber. ......................................................................