TITLE:
Relation between Gamma Decomposition and Powder Formation of γ-U8Mo Nuclear Fuel Alloys via Hydrogen Embrittlement and Thermal Shock
AUTHORS:
Fábio Branco Vaz de Oliveira, Delvonei Alves de Andrade
KEYWORDS:
Nuclear Fuel Alloys, Hydrogen Embrittlement, Thermal Shock
JOURNAL NAME:
World Journal of Nuclear Science and Technology,
Vol.4 No.4,
October
8,
2014
ABSTRACT: Gamma uranium-molybdenum alloys have been considered as the fuel phase in plate type fuel elements for material and test reactors (MTR), due to their acceptable performance under irradiation. Regarding their usage as a dispersion phase in aluminum matrix, it is necessary to convert the as cast structure into powder, and one of the techniques considered for this purpose is the hydration-dehydration (HDH). This paper shows that, under specific conditions of heating and cooling, γ-UMo fragmentation occurs in a non-reactive predominant mechanism, as shown by the curves of hydrogen absorption/desorption as a function of time and temperature. Our focus was on the experimental results presented by the addition of 8% weight molybdenum. Following the production by induction melting, samples of the alloys were thermally treated under a constant flow of hydrogen for temperatures varying from 500°C to 600°C and for times of 0.5 to 4 h. It was observed that, even without a massive hydration-dehydration process, the alloys fragmented under specific conditions of thermal treatment during the thermal shock phase of the experiments. Also, it was observed that there was a relation between absorption and the rate of gamma decomposition or the gamma phase stability of the alloy.