A HIGH-ALTITUDE NUCLEAR ENVIRONMENT SIMULATION by RYAN D. WHITE B.S., Kansas State University, 2008 A THESIS submitted in partial fulfillment of the requirements for the degree MASTER OF SCIENCE Department of Mechanical and Nuclear Engineering College of Engineering KANSAS STATE UNIVERSITY Manhattan, Kansas 2009 Approved by: Major Professor Dr. Kenneth Shultis i Abstract A program which calculates the radiation dosage to a predetermined set of components inside of a kill vehicle as a result of natural or artificial radiation sources has been developed for use within the confines of a parent external simulation. This dose can then be used to determine if a critical component has malfunctioned or failed completely, thereby rendering the interceptor unable to finish its mission. Knowledge of system and component performance as a function of incident high-energy particles leads to better battle management planning, CONOPS, and potentially a more efficient shielding design to achieve a higher probability of mission success. ii Table of Contents List of Figures................................................................................................................................ vi List of Tables ................................................................................................................................. ix CHAPTER 1 INTRODUCTION .............................................................................................. 1 1.1 Motivation for Present Work.......................................................................................... 1 1.2 Problem Overview.......................................................................................................... 2 1.3 Thesis Organization........................................................................................................ 3 CHAPTER 2 Sources of Radiation........................................................................................... 5 2.1 Natural Space Radiation ................................................................................................. 5 2.1.1 The AP8 and AE8 Models........................................................................................ 10 2.1.2 Limitations to the The AP8/AE8 Model................................................................... 13 2.2 Artificial Radiation Sources.......................................................................................... 14 2.2.1 Types of Artificial Radiation Associated with a Nuclear Burst ............................... 14 2.2.2 Flux Calculations ...................................................................................................... 16 2.2.3 Angle of Incidence.................................................................................................... 18 2.2.4 Atmospheric Attenuation of Particles....................................................................... 19 2.2.4.1 Line of Sight Calculations ................................................................................ 19 2.2.4.2 Method for Flux Attenuation ............................................................................ 23 2.2.4.3 Calculating Air Density at a Point .................................................................... 25 2.2.4.4 Integrating Air Density along a Line of Sight .................................................. 28 2.2.4.5 Limitations to the Atmospheric Models ........................................................... 32 2.2.4.6 Comments on the Atmospheric Attenuation Model ......................................... 35 2.2.5 Effects of Nuclear Bursts on Radiation Belts and Geomagnetic Fields ................... 36 2.2.5.1 The Starfish Prime Event.................................................................................. 36 2.2.5.2 The Magnetic Bubble........................................................................................ 38 2.2.5.3 Pumped Radiation Belts.................................................................................... 39 2.2.5.4 A Model for Radiation Belt Pumping............................................................... 41 2.3 Simulation Modeling Assumptions .............................................................................. 41 CHAPTER 3 Nature of the Program....................................................................................... 43 iii 3.1 Interface Assumption.................................................................................................... 43 3.2 How the Program Interacts with a Larger Simulation .................................................. 44 3.3 Simulation Model Inputs .............................................................................................. 46 3.3.1 Initial Inputs from a Larger Simulation .................................................................... 47 3.3.2 Running Inputs from a Larger Simulation................................................................ 47 3.3.3 List of Input Variables .............................................................................................. 48 3.4 Input File Formats......................................................................................................... 49 3.4.1 Interceptor Class Input Files..................................................................................... 50 3.4.2 Fission Class Input Files ........................................................................................... 51 3.5 Outputs to External Simulation..................................................................................... 51 3.6 Verification and Validation .......................................................................................... 51 CHAPTER 4 Recommended Enhancements .......................................................................... 53 4.1 Natural Radiation.......................................................................................................... 53 4.2 Artificial Radiation ....................................................................................................... 53 References..................................................................................................................................... 56 APPENDIX A MCNP Input File for Atmospheric Attenuation Testing .................................. 61 APPENDIX B Interceptor Class Definition ............................................................................. 63 B.1 Private Methods............................................................................................................ 63 B.2 Public Methods ............................................................................................................. 64 B.3 Private Members........................................................................................................... 66 B.4 Private Members........................................................................................................... 66 APPENDIX C Fission Class Definition.................................................................................... 67 C.1 Private Methods............................................................................................................ 67 C.2 Public Methods ............................................................................................................. 69 C.3 Private Members........................................................................................................... 73 C.4 Public Members............................................................................................................ 74 APPENDIX D FluxtoDose Class Definition............................................................................. 75 D.1 Private Methods............................................................................................................ 75 D.2 Public Methods ............................................................................................................. 77 D.3 Private Members........................................................................................................... 78 D.4 Public Members............................................................................................................ 78 iv APPENDIX E DoseMath Class Definition............................................................................... 79 E.1 Private Methods............................................................................................................ 79 E.2 Public Methods ............................................................................................................. 79 E.3 Private Members........................................................................................................... 80 E.4 Public Members............................................................................................................ 80 APPENDIX F VanAllen Class Definition................................................................................. 81 F.1 Private Methods............................................................................................................ 81 F.2 Public Methods ............................................................................................................. 83 F.3 Private Members........................................................................................................... 85 F.4 Public Members...........................................................................................................