2. Fuel rod and bundle performance

Lyhyt kuvaus

The objective of this topic is to assist SSM by reviewing the material provided by TVEL regarding the fuel rod and bundle performance of the TVS-K fuel.

The conditions of a nuclear reactor put great demands on the materials of the fuel. With use, the properties of the materials change and this may give rise to phenomena which needs to be considered. Several mechanisms may affect the fuel and these shall be reviewed and assessed.

The safety assessment should include, but is not limited by, cladding oxidation and hydriding, rod internal gas pressure, pellet cladding interactions, fuel gap activity, fuel fragmentation and cladding stability. The effects the water chemistry of Ringhals 3 may have on the cladding materials shall be assessed. Identification and evaluation of the margins built into the limiting values of for instance the linear heat generation rate shall be assessed. The thermal mechanical loads shall be assessed as well as the source activity and effects arising from increasing burn-up.