Location preferences of fission products in high density U(Mo) dispersion fuel element

In the frame of the RERTR Reduced Enrichment for Research and Test Reactors program a fuel element is being developed with the concept of high density bcc uranium that can remain stable during fabrication and later irradiation dispersed in aluminum powder The whole constitutes a compact material which is later rolled with an aluminum silicon clad plate Under further irradiation an interaction layer IL grows through a diffusion process around the fuel element particle leading to the swelling of the fuel element and formation of pores This behavior can lead to catastrophic failure of the disperse fuel Therefore it is our great interest to gain knowledge about the influence the fission products FP have over the IL formation and swelling The stable compounds that have been observed in the IL of U Mo Al Si tested in diffusion pair experiments are U Al Si USi U xSi x U Si UMo Al and U Mo Al Among them U Al Si has been observed to remain stable when subject to irradiation delaying or stopping the IL swelling Compositional analysis shows that La Ce Pr and Nd are some of the FP present in the burned dispersed fuel Hence these are the considered elements for a first evaluation of the problem that we performed in this work by means of computational methods