AER/I Seminar – Rachael Bergman

About the event

Speaker: Rachael Bergman

Title: Radiolysis Derived Hydrogen Gas from Alumina Species in Nuclear Waste

Group: Professor Xioafeng Guo

Abstract:

Originating from decades of supporting nuclear weapons production, the Hanford Site in Richland Washington is home to thousands of gallons of nuclear waste and consequently is the subject of discussions and research related to waste processing and storage. Aluminum-hydroxide species comprise a significant portion of the materials present in nuclear waste storage and are believed to be responsible for the introduction of hydrogen gas present in the storage tanks. The presence of this gas contributes to long term storage and processing issues due to its volatility, contribution to pressure buildup, and generation of secondary species within the storage tanks.  It is thought that high temperatures and exposure to neighboring radioactive materials contribute to the cleavage of hydrogen or hydroxyl groups from alumina species. Two alumina phase simulants, boehmite and gibbsite, have been studied to better understand the behaviors of these materials within the storage tanks following exposure to gamma radiation, under different temperature, and dehydration/rehydration conditions in order to best comprehend the environments at Hanford. This allows us to further our understanding of the origin of the problematic hydrogen through analysis of thermodynamically driven phase changes and bulk crystal structure.