Neutronic Analysis of Candidate Accident-Tolerant Cladding Concepts in Light Water Reactors

摘要

The neutronic penalty associated with a transition from Zircaloy cladding to iron-based alloy cladding materials for PWR fuel pins was quantified. Two routes for increasing core reactivity over the fuel lifetime were examined: increasing the uranium enrichment and increasing the fuel pellet diameter at the expense of cladding thickness. For ferritic alloys, a reduction in cladding thickness by roughly half or an increase in enrichment of about 1% resulted in enhanced core reactivity matching that of reference PWR bundles with Zircaloy cladding. For austenitic steels, the cladding thickness would have to be reduced to less than half, or the enrichment could be increased by approximately 1.5% to match the reactivity of Zircaloy PWR bundles.