Effect of Recrystallization on Gas Bubble Swelling in UMo Fuels

摘要

The development of low-enriched uranium (LEU) fuels such as UMo dispersion fuels and monolithic γ UMo fuels is part of a global effort on nuclear non-proliferation[1]. Although γ UMo fuels have the advantage of high density, excellent irradiation performance and good thermal conductivity, the volumetric swelling in irradiated metallic fuels is known to be an important design parameter because it affects not only the thermal conductivity of the fuels but also the mechanical integrity of fuel structures[2, 3]. Experiments also show that recrystallization dramatically affects the gas bubble swelling kinetics[2]. A series of materials processes such as casting, mechanical rolling and thermal treatment are used in fuel fabrication[4]. Resulting microstructure, such as grain size, porosity, and second phase, strongly depends on the material processes and process parameters. Therefore, a fundamental understanding how fabricated microstructures and irradiation conditions affect the nucleation of gas bubbles, recrystallization and gas bubble swelling kinetics is essential for optimizing material processes to obtain desired microstructure and fuel performance.