Date of Award

2010

Document Type

Campus Access Thesis

Department

Chemical Engineering

First Advisor

James Ritter

Abstract

Despite the fact that most fission products remain underground after a nuclear detonation a significant fraction of radioisotopes consisting of noble gases inevitably escape into the atmosphere and can be used to ascertain the occurrence of such detonations. Noble gas Xe radioisotopes, which are produced in large quantities in nuclear events and have relatively long half-lives, are ideal gas species for use for remote detection. Recently, a joint effort between Dr. Ritter's research group and National Security Directorate of the Pacific Northwest National Laboratory (NSD-PNNL) has been initiated to develop a process that exploits using pressure swing adsorption (PSA) principles for rapid xenon concentration from air and analysis for use in nuclear proliferation monitoring. The primary scope of this effort is to provide mathematical modeling support and other technical support to the NSD-PNNL for the development of new adsorption cycles for xenon concentration from air. The ultimate goal of this project is to work with the team at the PNNL to design a new version of the Automated Radioxenon Sampler-Analyzer (ARSA) that is significantly smaller and consumes much less power than the current version of ARSA developed by PNNL. Part of this goal will be accomplished through the use of a sophisticated modeling tool that Professor Ritter and his team have developed over the past decade called the Dynamic Adsorption Process Simulator (DAPS). This work will present initial calculations of a simplified design consisting of three Xe concentrators, starting with a rapid PSA system operating a room temperature and then followed by two hybrid PSA/TSA system. In addition the process will also treat air as a simple mixture of 86 ppb of Xe in N2, neglecting the existence of any other gas species that are typically found in air. Results indicate that the proposed system is able process about 500 SLPM of Xe-N2 mixtures to produce samples of around 6 cc containing 50 mol% Xe every 3 h. A description of all PSA systems and the effect of pertinent parameters in each concentrator will be given.

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