LOCA Safety Margin Improvement of CANFLEX-NU Fuel

Abstract

The CANFLEX-NU fuel has a lower peak linear heat generation rate and a higher critical heat flux compared to 37-rod standard fuel. The improvement on LOCA safety margin with use of CANFLEX-NU fuel was evaluated. The effect of relative power distribution in a bundle on initial core-wide fission product inventory distribution, the power pulse and the amount of fission product release by fuel failure following a large LOCA were analyzed and compared to those for 37-rod standard fuel. The margin for energetic fuel breakup due to power pulse is increased for CANFLEX-NU fuel. The amount of fission product release, and so the dose to the public, are reduced significantly compared to standard fuel due to the reduction of initial gap inventory and the number of failed fuel elements.