New results on fission gas release and molten fuel pressurization studies in the French pulsed reactor SILENE

The small scale in-pile SILENE experiments supply the quantitative information which is necessary to obtain the physical data bases used to describe the fission gas behaviour in irradiated mixed oxide UPuO2 during a severe thermal transient. Under these hypothetical accident conditions, the favourable phenomenon of fuel dispersal might occur due to the presence of the gases at a lower energy level, prior to fuel vaporization. Special measurements have also been made to investigate the possible role of the volatile fission products. The first part of the SILENE results covering 16 experiments performed earlier are described in references 1 to 3. The present paper relates to another 16 experiments performed since 1984. (author)