A New Modelling Framework for Radiation Protection
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UNIVERSITY OF SOUTHAMPTON FACULTY OF HUMAN AND SOCIAL SCIENCES Geography and Environment RADPOP: A New Modelling Framework for Radiation Protection by Becky Alexis-Martin Thesis for the degree of Doctor of Philosophy September 2016 UNIVERSITY OF SOUTHAMPTON ABSTRACT FACULTY OF HUMAN AND SOCIAL SCIENCES Geography and Environment Thesis for the degree of Doctor of Philosophy RADPOP: A NEW MODELLING FRAMEWORK FOR RADIATION PROTECTION Becky Alexis-Martin Ionising radiation is often useful to our society, and has been implemented for medicine, industry, energy generation and defence. However, nuclear and radiation accidents have the capacity to have a negative impact upon humans and may have a long-lasting legacy due to challenges associated with remediation and the slow decay of radionuclides. It is therefore a priority to ensure that there is adequate emergency preparedness, to prevent and manage any accidental release of ionising radiation to the communities that surround nuclear installations (NI). The emergency planning process includes desktop studies and exercises which are designed to examine the impact of hypothetical scenarios in real-time. However, greater spatiotemporal realism is required to understand the scale of a hypothetical radiation exposure to specific populations in space and time, to anticipate how the behaviour of the population will affect the outcome of an emergency, and to determine the strategy required for its management. This thesis presents a new modelling framework for radiation protection, called RADPOP. This framework combines spatiotemporal aggregate population density subgroup estimates with radionuclide plume dispersal modelling and agent-based modelling, to begin to understand how changes in spatiotemporal population density can influence the likelihood of exposure. Whilst sophisticated estimates of meteorological and atmospheric dispersal exist, there limited resources for the production of equivalent and contemporary high-resolution spatiotemporal population statistics. There is also no existing modelling framework for radiation protection and emergency preparedness, which implements spatiotemporal population estimates to understand the subsequent movement of an aggregate population, as it seeks shelter during a radiation emergency. This thesis investigates these challenges with focus upon the female population subgroup, as a group which has been identified in the literature as having greater vulnerability during evacuation. i Table of Contents Table of Contents ......................................................................................................... ii List of Tables ................................................................................................................ ii List of Figures ............................................................................................................... ix DECLARATION OF AUTHORSHIP ................................................................................... xv Acknowledgements ................................................................................................... xvii Abbreviations ............................................................................................................. xix Chapter 1: Introduction ....................................................................................... 1 1.1 Why is a new modelling framework for radiation emergency planning required? 1 1.2 Aims and Objectives ................................................................................................ 2 1.3 Thesis Structure ....................................................................................................... 3 1.4 Novel Contributions ................................................................................................. 4 Chapter 2: Spatiotemporal Population Modelling ................................................ 5 2.1 The Challenges of Modelling Population Data ........................................................ 6 2.2 Interpolating Spatially Distributed Phenomena ...................................................... 8 2.3 Summary of Interpolation Methods for Modelling Population Density ................. 9 Pycnophylactic Interpolation .................................................................. 10 Distance Weighting ................................................................................. 11 Kriging ...................................................................................................... 12 Kernel Density Estimation ....................................................................... 12 Dasymetric Interpolation ........................................................................ 14 Spatiotemporal Population Modelling .................................................... 17 Hagerstrand’s space-time geography ..................................................... 18 2.4 Temporal GIS ......................................................................................................... 19 The Three Domain t-GIS Approach.......................................................... 23 Population247 ......................................................................................... 25 2.5 Dynamic Spatiotemporal Population Modelling ................................................... 27 2.6 Chapter Conclusions .............................................................................................. 30 Chapter 3: Radiation Protection and Society ....................................................... 31 ii 3.1 Technological Hazard, Risk and Vulnerability ........................................................ 31 Vulnerable Population Subgroups ........................................................... 34 3.2 Humans and Radiation ........................................................................................... 35 The Health Effects of Radiation Exposure ............................................... 38 The Effects of Radiation Exposure upon Children and Females .............. 40 Treating Exposure to Radiation ............................................................... 42 3.3 Emergency Planning and Management for Radiation Hazards ............................. 43 Introduction to Emergency Planning ....................................................... 43 Planning for and Managing Radiation Hazards ....................................... 44 Nuclear Submarine Radiation Hazards and the Chazhma Bay Accident . 47 The Chernobyl Reactor Accident ............................................................. 49 3.4 Modelling Radiation Dispersal ............................................................................... 51 3.5 Modelling Populations at Risk for Emergency Planning ........................................ 52 Approaches to Modelling Risk to Populations for Emergency Planning . 54 3.6 Modelling Populations at Risk using Agent-Based Modelling ............................... 61 3.7 Chapter Conclusions .............................................................................................. 69 Chapter 4: Methodology.................................................................................... 71 4.1 Introduction ........................................................................................................... 71 4.2 Component A: Modelling Populations in Space and Time .................................... 73 Constructing Datasets for Population247 ............................................... 78 Destination Populations .......................................................................... 81 4.3 Component B: Assessment of Hazard Distribution and Health Effects ................. 87 PACE ......................................................................................................... 87 Health Effects Methodology for PACE ..................................................... 89 NAME ....................................................................................................... 90 4.4 Component C: Understanding changes in population distribution during emergencies ........................................................................................................... 97 Introduction ............................................................................................. 97 Agent based modelling ............................................................................ 97 iii Netlogo .................................................................................................... 98 Modelling evacuation in Netlogo .......................................................... 100 Model entities and processes ............................................................... 104 Model outputs ....................................................................................... 107 Chapter 5: Case study I: Daytime exposure during a hypothetical radiation emergency ................................................................................................. 109 5.1 Overview .............................................................................................................. 109 5.2 Case study I context ............................................................................................. 109 HMNB Royal Dockyard Devonport, a relevant existing nuclear installation site ...................................................................................... 111 The City of Exeter, the case study hypothetical scenario site............... 112 5.3 Study