Prepation of Generic Oxides Melt Model for Late-Phase Severe Accident Analysis

2016 Fiscal Year Final Research Report

• Project/Area Number: 26630484
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Nuclear engineering
• Research Institution: Nagaoka University of Technology
• Principal Investigator: Thi Mai Dung Do 長岡技術科学大学, 工学研究科, 助教 (90638420)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: cesium molybdate / vaporization / Cs2MoO4-MoO3 / Cs-Mo-O-H system / Cs2Mo2O7 / thermodynamics / severe accident

Outline of Final Research Achievements

The high-temperature behavior of Cs2MoO4 in H2O+H2 gas was studied in order to better understand the behavior of cesium in the severe accident of the LWR. The pseudo-binary system, Cs2MoO4-MoO3, was thermochemically modeled with Redlich-Kister formulation, and the IMCC model has been also examined for the liquid mixtures of Cs2MoO4 and Cs2Mo2O7. Thermochemical model was further applied to predict the partitioning of cesium and molybdenum among gaseous species in the LWR core degradation condition, which is typical of Short-Term Station Blackout.
Vaporization behavior of Cs2Mo2O7 was clarified. Reactions of Cs2MoO4 with SUS in dry and humid atmosphere were studied. It was clarified that Cs2MoO4 was decomposed mostly by the reaction with Cr in dry condition. In humid condition, the reaction seemed to be limited to result in a very small fraction of molybdenum incorporation in the oxide scale.

Free Research Field

materials science