EXCLUSION ZONES FOR SMALL MODULAR REACTORS A Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements For the Degree of Master of Applied Science in Industrial Systems Engineering University of Regina by Bradley Edward Rudolph Lulik Regina, Saskatchewan March 2020 Copyright 2020: B.E.R. Lulik UNIVERSITY OF REGINA FACULTY OF GRADUATE STUDIES AND RESEARCH SUPERVISORY AND EXAMINING COMMITTEE Bradley Edward Rudolph Lulik, candidate for the degree of Master of Applied Science in Industrial Systems Engineering, has presented a thesis titled, Exclusion Zones for Small Modular Reactors, in an oral examination held on March 27, 2020. The following committee members have found the thesis acceptable in form and content, and that the candidate demonstrated satisfactory knowledge of the subject material. External Examiner: Dr. Irfan Al-Anbagi, Electronic Systems Engineering Co-Supervisor: Dr. Esam Hussein, General Engineering Co-Supervisor: Dr. David deMontigny, Industrial Systems Engineering Committee Member: Dr. Adisorn Aroonwilas, Industrial Systems Engineering Committee Member: Dr. Golam Kabir, Industrial Systems Engineering Chair of Defense: Dr. Christopher Yost, Department of BIology All Participated via ZOOM Abstract The objective of this thesis is to estimate the size of the exclusion zone around a small modular reactor (SMR). The aim of such zone is to provide an atmospheric space sufficient to dilute any radioactive releases during an accident, to a level below the safe regulated radiation dose for the public. A hypothetical severe accident is considered for a generic SMR, and the whole-body radiation dose associated with the accident was estimated at various distances and reactor power levels. The results were verified against those of a more complex model for a typical CANDU reactor. The obtained results were then employed to estimate the radius of the exclusion zone, by determining the distance at which the dose is at or slightly below the permitted dose to a member of the public. The method first estimates the quantity and type of radioactive materials available for release to the environment following a nuclear accident, known as the Source Term. This thesis employed a simplified approach for estimating the Source Term, utilizing the magnitude of the fission product yields, radionuclide release fractions, and reactor thermal power. The estimated Source Term values were then used as input to an atmospheric plume dispersion model, to determine the radiation dose at various distances after dilution. The HotSpot Health Physics code was employed to estimate the radiation dose, because it is a convenient and efficient tool for the many calculations associated with the numerous radionuclides that would be released during a postulated reactor accident. In addition to the effect of atmospheric dilution of radionuclides, the thesis also examined how the size of the exclusion zone is influenced by technical regulations and standards, reactor design and safety features, and by the presence of engineered barriers. ii Further, this thesis presents a survey of SMR designs currently in development and a review of their unique safety features. iii Acknowledgements I wish to acknowledge my co-supervisor, mentor, and friend Dr Esam Hussein. During my time at the University of Regina, I have had the privilege of learning from Dr Hussein. I am immensely grateful for his continued guidance, support, encouragement, and patience. The Faculty of Engineering and Applied Science is blessed to have Dr Hussein as Dean. I would like to express my appreciation to my co-supervisor Dr David deMontigny. Over the past eight years, both as an undergraduate and graduate student, it has been a privilege to work with Dr deMontigny. His commitment to the quality of education being provided by the Faculty of Engineering and Applied Science is beyond compare. To the Silvia Fedoruk Canadian Centre for Nuclear Innovation’s Board of Directors, thank you for seeing the value in developing Saskatchewan’s technical capacity related to the siting of Small Modular Reactors. I am grateful for the monetary support that has allowed me to complete my work and appreciative of the opportunity to participate on this multidisciplinary project. iv Dedication To my wife, Justine, for her unconditional love, support, and patience throughout this endeavour and others. To my parents, Debbie and Emil, for their love, encouragement, and continued interest in my studies. v Table of Contents Abstract ........................................................................................................................................... ii Acknowledgements ....................................................................................................................... iv Dedication ....................................................................................................................................... v Table of Contents .......................................................................................................................... vi List of Tables ............................................................................................................................... viii List of Figures ................................................................................................................................ ix CHAPTER 1: INTRODUCTION ................................................................................................ 1 1.1 Small Modular Reactors ........................................................................................................ 1 1.2 Canadian Regulations ............................................................................................................ 3 1.3 Exclusion Zone ...................................................................................................................... 5 1.4 Thesis Objectives and Outline ............................................................................................... 7 CHAPTER 2: SOURCE TERM .................................................................................................. 9 2.1 Introduction ............................................................................................................................ 9 2.2 Source Term ......................................................................................................................... 10 2.3 Approximation ..................................................................................................................... 11 2.4 Source Term Verification .................................................................................................... 12 2.5 Sensitivity Analysis ............................................................................................................. 14 2.6 Conclusions .......................................................................................................................... 18 CHAPTER 3: RADIOACTIVITY DISPERSION AND EXCLUSION ZONE .................... 19 3.1 Introduction .......................................................................................................................... 19 3.2 HotSpot ................................................................................................................................ 20 3.3 Verification .......................................................................................................................... 23 3.4 Exclusion Zone for SMRs .................................................................................................... 28 3.5 Sensitivity Analysis ............................................................................................................. 29 3.6 Conclusions .......................................................................................................................... 33 CHAPTER 4: REDUCING EXCLUSION ZONE THROUGH DESIGN .............................. 34 4.1 Introduction .......................................................................................................................... 34 4.2 The Exclusion Zone ............................................................................................................. 35 4.3 Inherent and Passive Safety ................................................................................................. 37 4.4 Reactor Material................................................................................................................... 39 4.5 Engineered Features and Barriers ........................................................................................ 41 4.6 Conclusions .......................................................................................................................... 43 CHAPTER 5: CONCLUSIONS ................................................................................................. 45 5.1 Summary .............................................................................................................................. 45 5.2 Conclusions .......................................................................................................................... 47 5.3 Contribution to Knowledge .................................................................................................. 48 5.4 Recommendations for Future Work ..................................................................................... 48 vi REFERENCES ............................................................................................................................