Basic aspects of swelling in dense livuid metal fast breeder reactor fuels

Abstract

The basic aspects of swelling in dense livuid metal fast breeder reactor fuels, alloys, carbides and nitrides, are analysed as functions of burn-up by use of a common reduced temperature scale. In addition to temperature and burn-up, swelling depends on stress and the composition and as-fabricated structure of the fuel. Therefore the technological boundary conditions, as defined by pin design and operation parameters, have to be respected in order to limit the analysis. This leads to the concepts of “hot” fuels, “cool” fuels as well as free swelling and swelling under restraint. With increasing burn-up the in-pile kinetics responsible for swelling are affected by the ingrowth of fission damage and the increasing concentration of fission products. The resulting phenomena are not yet well understood and represent a field of present and future research.