http://hdl.handle.net/1957/18496 2013-05-26T06:15:09Z 2013-05-26T06:15:09Z Makinson, Kevin A. http://hdl.handle.net/1957/38468 2013-05-06T21:25:21Z 2013-04-19T00:00:00Z

Preliminary framework for the run-ahead predictive simulation software (RAPSS) Makinson, Kevin A. The Run-Ahead Predictive Simulation Software (RAPSS) is an architecture designed for faster-than-real-time decision support for operators of complex networks. To enable further development of the RAPSS methodology, the necessary proof of principle is illustrated in two applications: decision support for shift technical advisors in nuclear power plant control rooms (RAPSS-STA), and in the event of a release outside of containment, decision support for emergency operation centers (RAPSS-EOC). Graduation date: 2013

2013-04-19T00:00:00Z Dickson, Elijah D. http://hdl.handle.net/1957/38431 2013-05-02T20:06:42Z 2013-04-11T00:00:00Z

Experimental shielding evaluation of the radiation protection provided by residential structures Dickson, Elijah D. The human health and environmental effects following a postulated accidental release of radioactive material to the environment has been a public and regulatory concern since the early development of nuclear technology and researched extensively to better understand the potential risks for accident mitigation and emergency planning purposes. The objective of this investigation is to research and develop the technical basis for contemporary building shielding factors for the U.S. housing stock. Building shielding factors quantify the protection a certain building-type provides from ionizing radiation. Much of the current data used to determine the quality of shielding around nuclear facilities and urban environments is based on simplistic point-kernel calculations for 1950’s era suburbia and is no longer applicable to the densely populated urban environments seen today. To analyze a building’s radiation shielding properties, the ideal approach would be to subject a variety of building-types to various radioactive materials and measure the radiation levels in and around the building. While this is not entirely practicable, this research uniquely analyzes the shielding effectiveness of a variety of likely U.S. residential buildings from a realistic source term in a laboratory setting. Results produced in the investigation provide a comparison between theory and experiment behind building shielding factor methodology by applying laboratory measurements to detailed computational models. These models are used to develop a series of validated building shielding factors for generic residential housing units using the computational code MCNP5. For these building shielding factors to be useful in radiologic consequence assessments and emergency response planning, two types of shielding factors have been developed for; (1) the shielding effectiveness of each structure within a semi-infinite cloud of radioactive material, and (2) the shielding effectiveness of each structure from contaminant deposition on the roof and surrounding surfaces. For example, results from this investigation estimate the building shielding factors from a semi-infinite plume between comparable two-story models with a basement constructed with either brick-and-mortar or vinyl siding composing the exterior wall weather and a typical single-wide manufactured home with vinyl siding to be 0.36, 0.65, and 0.82 respectively.; The human health and environmental effects following a postulated accidental release of radioactive material to the environment has been a public and regulatory concern since the early development of nuclear technology and researched extensively to better understand the potential risks for accident mitigation and emergency planning purposes. The objective of this investigation is to research and develop the technical basis for contemporary building shielding factors for the U.S. housing stock. Building shielding factors quantify the protection a certain building-type provides from ionizing radiation. Much of the current data used to determine the quality of shielding around nuclear facilities and urban environments is based on simplistic point-kernel calculations for 1950’s era suburbia and is no longer applicable to the densely populated urban environments seen today. To analyze a building’s radiation shielding properties, the ideal approach would be to subject a variety of building-types to various radioactive materials and measure the radiation levels in and around the building. While this is not entirely practicable, this research uniquely analyzes the shielding effectiveness of a variety of likely U.S. residential buildings from a realistic source term in a laboratory setting. Results produced in the investigation provide a comparison between theory and experiment behind building shielding factor methodology by applying laboratory measurements to detailed computational models. These models are used to develop a series of validated building shielding factors for generic residential housing units using the computational code MCNP5. For these building shielding factors to be useful in radiologic consequence assessments and emergency response planning, two types of shielding factors have been developed for; (1) the shielding effectiveness of each structure within a semi-infinite cloud of radioactive material, and (2) the shielding effectiveness of each structure from contaminant deposition on the roof and surrounding surfaces. For example, results from this investigation estimate the building shielding factors from a semi-infinite plume between comparable two-story models with a basement constructed with either brick-and-mortar or vinyl siding composing the exterior wall weather and a typical single-wide manufactured home with vinyl siding to be 0.36, 0.65, and 0.82 respectively. Graduation date: 2013

2013-04-11T00:00:00Z Wheeler, Adam (Adam Richard) http://hdl.handle.net/1957/38011 2013-04-04T17:43:01Z 2013-03-20T00:00:00Z

Modeling and analysis of a heat transport transient test facility for space nuclear systems Wheeler, Adam (Adam Richard) The purpose of this thesis is to design a robust test facility for a small space nuclear power system and model its physical behavior under different scenarios. The test facility will be used to simulate a 1-10kWe nuclear reactor, its electrical generation, and heat removal capabilities. This simulator will be used to explore, test and understand the steady-state and transient operation capabilities of small space nuclear power systems. Currently, the system is planned to operate on a variable, electrical heat source directly connected to heat pipes. The heat pipes are to be stainless steel with a water working fluid. These heat pipes will then be connected to a power conversion simulator or actual power conversion technologies. The power conversion simulator is connected to a radiator using a water based heat pipe network using fins and connecting plates in a cylindrical geometry. Modeling of the facility was performed using two different analysis programs, STELLA and SolidWorks. STELLA was used as a lumped sum heat transport code, and SolidWorks was used as a more accurate system to verify the validity of STELLA's results. Both programs were used to analyze startup, heat pipe failures, and loss of power conversion with the end goal of finding safe operational transient scenarios for the transient test facility. Graduation date: 2013

2013-03-20T00:00:00Z Farsoni, A. T. Alemayehu, B. Alhawsawi, A. Becker, E. M. http://hdl.handle.net/1957/37995 2013-04-03T20:29:54Z 2013-02-01T00:00:00Z

A Phoswich Detector with Compton Suppression Capability for Radioxenon Measurements Farsoni, A. T.; Alemayehu, B.; Alhawsawi, A.; Becker, E. M. A phoswich detector with Compton suppression capability has been developed and tested for measuring xenon radioisotopes via a beta-gamma coincidence measurement technique. The phoswich detector has been designed with three scintillation layers. Beta-gamma coincidence events from radioxenon isotopes are identified when a coincidence energy absorption is detected in the first (BC-400) and second (CsI(Tl) crystal) scintillation layers. To identify and reject scattered photons from the CsI(Tl) crystal, the crystal is surrounded by a BGO scintillation layer. Our measurements show that the Compton suppression mechanism reduces the Compton continuum from 662 keV photons by 20%-50% in the low-energy region of spectrum. Our beta-gamma coincidence measurements with ¹³⁵Xe and ¹³³Xe radioisotopes show energy resolutions (FWHM) of 13%, 46% and 24% for 250 keV, 30keV and 80 keV gamma-ray peaks, respectively. In this paper, the detector design, assembly steps, digital pulse shape discrimination technique, and our recent measurements with radioactive lab sources and xenon radioisotopes are discussed. This is the author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by IEEE-Institute of Electrical and Electronics Engineers and can be found at: http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=23. (c) 2013 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.

2013-02-01T00:00:00Z