Design and Safety Assessment of Slightly Enriched Fuel Elements for CANDU Reactors

Abstract

Fuel with very slight enrichment allows for an increase in the number of full power days for a 37-element fuel bundle. Consequently sheath strain, FGR, and fuel temperature are affected. The goal is to confirm that safety margins could be maintained, with some minor fuel design enhancements. The effect of selected design parameters on safety margins has been assessed. A systematic design study confirms that sheath strain and FGR could be maintained, when compared with the current predicted values. It was found that current manufacturing parameters are fully capable to maintain safety margins for a desired enrichment of 0.75% Uranium-235. Three enhanced fuel designs have also been presented which reduce the effects of enrichment.