ECONOMIC ASSESSMENT OF ACCIDENT TOLERANT FUEL CLADDING OPTIONS

摘要

If an accident tolerant fuel cladding is to replace the zirconium alloys, it will have to be economically viable. Four proposed materials are examined as cladding options: Stainless steel (SS), FeCrAl alloy, molybdenum (Mo) tri-layer composite and silicon carbide ceramic matrix composite (SiC CMC), each having its own development time and costs. The thickness of each cladding was assumed to reflect the strength of the material and its manufacturing limits. The UO_2 enrichment savings or penalty was calculated for each cladding option relative to Zircaloy, given unit costs from recent market conditions. Based on this analysis, it was found that all options may end up requiring higher enrichment for the same fuel cycle length. SiC will likely be the least cost option. If the present value of avoiding a large reactor accident with a large radioactivity release is estimated using past experience for LWR large accidents, there is a definite net economic benefit relative to typical Zircaloy cladding only in using SiC CMC as a cladding material, when the ATF cladding is assumed capable of preventing reactor loss and radioactivity release in a Fukushima-type event. Because of the high enrichment costs relative to accident costs, there is only a marginal economic benefit in using SiC to prevent a core-only loss without radioactivity release (TMI-type) accident and a large economic loss using metallic ATF concepts.