Fabrication of highly-loaded low-enrichment uranium aluminide fuel plates

EG and G Idaho has been experimenting with the fabrication of highly-loaded low-enrichment uranium aluminide fuel plates at the Idaho National Engineering Laboratory. This is a report of the progress during fiscal year 980. The objectives of the program were twofold. The first was to develop the processes for producing experimental fuel plates with maximum practical UAlx loadings using the standard roll-bonding technique. The EG and G facility duplicates in miniature a commercial fuel fabrication facility, so processes which are developed for fabricating these plates can then be easily translated to a commercial scale operation. The second objective was to demonstrate that plates fabricated using these processes will perform satisfactorily in a reactor. The target burnup was 60 to 80% of the fissile atoms. The plates consisted of cores of uranium aluminide, UAlx in a matrix of aluminum, roll bonded to 6061 aluminum picture frames and covers. The mating surfaces were clad with 1100 aluminum to facilitate bonding. These plates were loaded from 40 to 56 volume percent UAlx. Most of these plates were fabricated using 44 to 149 μm UAlx, although some cores have been fabricated with UAIx particles sizes less than 44 μm to determine the effect of particle size on the fabricability and on the irradiation performance. There were three major producibility problems to address: excessive variation in core thickness, that is, variation along the length of the core in its thickness; excessive over-all core thickness; and excessive thickening at the core ends (dogboning)