Parametric study of thermal feedback and other transient effects, based on the INTERPIN code

This paper discusses the INTERPIN code, used for parametric sensitivity studies of thermal feedback. The variational parameter was the thermal gap prior to an overpower. The author states that INTERPIN, which models the fission gas release in a truly transient way, showed that for large gap prior to the overpower, significant gas release may be expected during a fast power increase, with continuing release during the overpower. In contrast, for small gap the release during the power rise may be negligible, while significant release can be expected during the first hours of the overpower, subject to grain boundary saturation. The findings are supported by a simplified analytical theory