Specific features of UMo fuel - Al matrix interaction

Under discussion is mechanism of pore formation on interaction layer -- matrix boundary via locally build-up of fission products on boundary and interaction layer growth of by-passing local aggregates. Diffusion barriers available in aluminium matrix produced from SAP (sintered aluminium powder) as fine layers of Al2O3 decrease UMo fuel - aluminium interaction under out of pile conditions. It is shown that irradiation induced formation of (UMo)Al7 or (UMo)Al3 type structures depends on fission rate - fuel temperature ratio. The results of in-pile tests RERTR (1-5), IRIS (1-2), KOMO-2, RIAR and Zarechny are discussed that comply with suggested schema. Consideration is given to influence of silicon available in aluminium matrix on specific features of Al - UMo alloy interaction. It is demonstrated that the influence of silicon is primarily determined by its interaction with the first formed interaction layer UAl3 on UMo particle (author)