PLASTIC STRAIN IN THIN FUEL ELEMENT CLADDING DUE TO UOsub2sub 2 THERMAL EXPANSION

Results are presented of short time, high heat flux capsule irradiations to determine the magnitude of plastic strain induced in the capsule cladding due to UO/sub 2/ thermal expansion. Annular geometry capsules were employed with both internal and external cladding and forced convection cooling of both surfaces to simulate the reference superheat fuel element design. Both 304 stainless steel and 3003 aluminum claddings of various thickness were used to determine the influence of cladding strength. The initial gap spacing was purposely varied as an additional parameter. The program was undertaken as a part of the effort to evaluate plastic strain cycling as life limitation in the use of thin fuel element cladding. An over-all summary of the experimental results is included. (auth