Seminar: Noble Gas Nuclear Forensics

Abstract

Since the Partial Test Ban Treaty in 1963, nuclear explosion tests have largely been conducted in underground locations.  To monitor the emissions from underground nuclear tests, the world community relies upon atmospheric monitoring for radioxenon among other technologies.  The Comprehensive Nuclear Test-Ban Treaty (CTBT) incorporates radioxenon monitoring within International Monitoring System (IMS) with a focus on 131mXe, 133mXe, 133Xe, and 135Xe.  It is expected that radioxenon monitoring will also be incorporated into the On-Site Inspection (OSI) protocols along with radioargon monitoring.

When an atmospheric radioxenon signal is observed, the isotopic ratios are examined to see if they match the expected values for nuclear explosions.  These isotopic ratios are utilized to distinguish between nuclear explosion sources of radioxenon and other anthropogenic sources such as the commercial nuclear industry and the radiopharmaceutical industry.  Current methods to predict the various isotopic ratio signatures have largely focused on modeling the production source.  While this is a good first order approximation, it does not account for the chemical and isotopic fractionation that occurs during environmental transport of radioxenon and its parent radionuclides.  This fractionation causes a significant change in the isotopic ratios from their point of creation to the point where they are collected in the atmosphere.

This seminar will focus on developments at The University of Texas at Austin that advance the field of noble gas nuclear forensics.  Analysis will be shown for both natural and anthropogenic signals and forensic methods for distinguishing between radioxeon sources will be discussed.  A forensic assessment of radioxenon emissions from the Fukushima nuclear accident will be presented and results showing the variability induced by underground radionuclide transport will be detailed.

About the Speaker

Steven Biegalski is currently the Director of the Nuclear Engineering Laboratory (NETL) and a Professor in the Mechanical Engineering Department. He is licensed as a Professional Engineer in the states of Texas and Virginia. His research focuses on nuclear analytical methods, nuclear instrumentation, nuclear reactor design, and nuclear reactor operations. Dr. Biegalski has published 184 peer-reviewed publications and has advised 21 Ph.D. students to graduation.  He is an Associate Editor for the Journal of Radioanlytical and Nuclear Chemistry.

Hosted by Professor Lei R. Cao