The behavior of zircaloy cladding during the loss of coolant accidents at Three Mile Island (TMI) in the US and
the Fukushima reactors in Japan was the major cause of overheating and hydrogen release. An alternate
cladding material, consisting of multiple layers of silicon carbide fiber matrix composite and silicon carbide
high density monolith, (called SiC TRIPLEX cladding) is being developed in the US that offers reliable service
during normal reactor operation, and a very large reduction in the exothermic reaction and hydrogen generation
that occurred in these accidents. Should another loss of coolant accident occur in a power reactor somewhere in
the world, as it surely will someday, use of this cladding would avoid the severe core damage and allow
recovery of the plant without total core destruction as occurred at Fukushima and TMI. The status of
development and testing of this TRIPLEX cladding is described, as are the plans for future development and
testing in preparation for licensing and use. A separate program for replacement of zircaloy channel boxes in
BWRs with a unique form of SiC-SiC composite, is also described.
Keywords
Fuel cladding, hydrogen generation. loss of coolant accident, silicon carbide
Full Paper:PDFEJAM Vol.5No.2 pp.128-131 "Silicon Carbide TRIPLEXTM Fuel Clad and SiC Channel Boxes for
Accident Resistance and Durability
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