NOT PROTECTIVELY MARKED Page No.: i / iii REDACTED PUBLIC VERSION HPC PCSR3 – Sub-chapter 17.2 – Reference: Demonstration of Relevant Good Practice HPC-NNBOSL-U0-000-RES- 100098 and Optioneering in the Initial EPR Design NNB GENERATION COMPANY (HPC) LTD REDACTED PUBLIC VERSION HPC PCSR3: CHAPTER 17 – COMPLIANCE WITH ALARP SUB-CHAPTER 17.2– DEMONSTRATION OF RELEVANT GOOD PRACTICE AND OPTIONEERING IN THE INITIAL EPR DESIGN { PI Removed } APPROVED © 2017 Published in the United Kingdom by NNB Generation Company (HPC) Limited, 40 Grosvenor Place, Victoria, London SW1X 7EN. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, including photocopying and recording, without the written permission of the copyright holder NNB Generation Company (HPC) Limited, application for which should be addressed to the publisher. 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APPROVED NOT PROTECTIVELY MARKED NOT PROTECTIVELY MARKED Page No.: iii / iii REDACTED PUBLIC VERSION HPC PCSR3 – Sub-chapter 17.2 – Reference: Demonstration of Relevant Good Practice HPC-NNBOSL-U0-000-RES- 100098 and Optioneering in the Initial EPR Design TABLE OF CONTENTS 1. INTRODUCTION .................................................................................. 1 2. INITIAL EPR DESIGN PROCESS ....................................................... 2 2.1. ORGANISATIONS INVOLVED IN INITIAL EPR DESIGN AND LICENSING .......................................................................................... 2 2.2. MAIN PHASES OF THE INITIAL EPR PROJECT ............................... 4 2.3. PRODUCTION OF “TECHNICAL GUIDELINES” ............................... 5 2.4. REVIEW AND VALIDATION OF EPR DESIGN OPTIONS ................. 6 2.5. SUMMARY OF R&D WORK UNDERPINNING THE EPR DESIGN .. 10 3. CODES AND STANDARDS USED FOR EPR DESIGN .................... 11 4. INCORPORATION OF EXPERIENCE FEEDBACK INTO THE INITIAL EPR DESIGN ........................................................................ 12 5. COMPARISON OF EPR DESIGN WITH NATIONAL AND INTERNATIONAL STANDARDS ....................................................... 13 6. OUTCOME OF OPTIONEERING PROCESS – SAFETY SYSTEMS/STRUCTURES ................................................................. 14 6.1. GENERAL DESIGN PRINCIPLES ..................................................... 14 6.2. RESULTS OF DESIGN OPTIMISATION ........................................... 15 7. DOSES TO WORKERS IN ACCIDENTS ........................................... 24 8. OPTIMISATION OF DOSE TO WORKERS AND THE PUBLIC IN NORMAL OPERATION ..................................................................... 25 8.1. MINIMISATION OF DOSE TO WORKERS........................................ 25 8.2. DOSE TO MEMBERS OF THE PUBLIC IN NORMAL OPERATION ...................................................................................... 27 9. USE OF PSA STUDIES IN THE EPR DESIGN ................................. 28 10. CONCLUSIONS ON INITIAL EPR DESIGN REGARDING ALARP .. 29 11. REFEREAPPROVEDNCES ................................................................................... 31 NOT PROTECTIVELY MARKED NOT PROTECTIVELY MARKED Page No.: 1 / 44 REDACTED PUBLIC VERSION HPC PCSR3 – Sub-chapter 17.2 - Reference: Demonstration of Relevant Good Practice HPC-NNBOSL-U0-000-RES- and Optioneering in the Initial EPR Design 100097 SUB-CHAPTER 17.2 - DEMONSTRATION OF RELEVANT GOOD PRACTICE AND OPTIONEERING IN THE INITIAL EPR DESIGN 1. INTRODUCTION This sub-chapter summarises how the initial EPR design was established with the aim of reducing the risks posed to workers and members of the public. Firstly, the relevant good practice and standards applied in the initial EPR design process are described, followed by a comparison against national and international standards. Then the design optioneering process carried out in France and Germany between 1987 and 2006 to develop the initial EPR design, and the design review carried out by independent safety experts on behalf of the French and German safety authorities are described. In addition, this sub-chapter presents the outcome of the design optioneering process in terms of the principal design options that were selected and rejected to achieve a balanced design that minimised risk to workers and the public, whilst achieving practical constructability and a cost- effective design. The rationale for the evolution from the initial design, and the improvements from former designs, are explained together with the reasons why certain features were selected and others rejected. The Hinkley Point C (HPC) EPR design is derived from this initial EPR design following an As Low As Reasonably Practicable (ALARP) process as outlined in Sub-chapter 17.3. This sub-chapter is organised as follows: Section 2 describes the review of the experience of the EPR designers and a summary of the review and assessment process applied to the design including a summary of the Research and Development (R&D) effort underpinning the EPR design. Section 3 describes the review of the design codes used in the initial EPR design and the HPC design (reference is made to Sub-chapter 3.8). Section 4 describes how the operational feedback from French and German plants was incorporated in the initial EPR design. Section 5 describes the assessment of the EPR design against national and international standards. Section 6 describes the optioneering of safety systems and structures protecting against accidentalAPPROVED release of radioactivity. Sections 7 and 8 describe the optimisation of the initial EPR design to minimise doses to workers and the general public due to plant operation in normal, fault and hazard conditions. Section 9 describes the role played by the Probabilistic Safety Assessment (PSA) in achieving an initial EPR design which minimises risk. NOT PROTECTIVELY MARKED NOT PROTECTIVELY MARKED Page No.: 2 / 44 REDACTED PUBLIC VERSION HPC PCSR3 – Sub-chapter 17.2 - Reference: Demonstration of Relevant Good Practice HPC-NNBOSL-U0-000-RES- and Optioneering in the Initial EPR Design 100097 Section 10 presents the conclusion that, although formal principles of ALARP were not applied as an integral part of the initial EPR design, the process followed was analogous to the formal UK ALARP approach. 2. INITIAL EPR DESIGN PROCESS The EPR is a Generation 3+ Pressurised Water Reactor (PWR) design developed by the Nuclear Power International (NPI) - now AREVA NP - a joint subsidiary of Framatome and Siemens, using experience gained by EDF, the German Utilities, Framatome and Siemens in the design, manufacturing, construction, and operation of PWRs (corresponding to over 1,000 reactor-years of operation). The reactor has been designed to meet safety specifications developed by the French Nuclear Regulatory Authority (ASN) as set down in the Technical Guidelines (TG) [Ref. 1]. These guidelines were developed following an extensive optioneering process, carried out in France and Germany between 1987 and 2000, on the design of a Generation 3 PWR suitable for construction in Europe in the 21st century. The outcome of the optioneering exercise was reviewed by independent safety experts from several European Countries and the United States of America (USA), on behalf of the French and German regulatory authorities. A description of the design development and design review process and the organisations involved is given below. 2.1. ORGANISATIONS INVOLVED IN INITIAL EPR DESIGN AND LICENSING The three main types of organisations involved in the design and licensing process of the initial EPR design have been the design organisations, the French and German Regulators or safety authorities and the bodies appointed to provide technical support to the safety authorities. A description of these bodies and their roles is given below. The organisational arrangements are shown in Sub-chapter 17.2 - Tables 1 and 2. 2.1.1. Design Organisations The EPR design organisations consist of reactor vendor and utility companies from France and Germany. The EPR project began in 1987 when the vendor companies Framatome and Siemens began co-operation to develop and commercialise a common PWR design aimed at the international export market. The aim of the collaboration was to pool the experience of the two companies in order to share the huge effort involved in developing a new reactor design. The companies founded a joint subsidiary company NPI to lead the work. Within a short time French and German electricalAPPROVED utilities had joined the project, which rapidly replaced other reactor development programmes underway in France and Germany. The new reactor design was renamed EPR. NPI (now AREVA NP) led