EFFECTS OF HIGH BURNUP ON ZIRCALOY-CLAD BULK UO$sub 2$, PLATE FUEL ELEMENT SAMPLES
- 1 September 1962
- report
- Published by Office of Scientific and Technical Information (OSTI)
Abstract
The results of irradiation testing of Zircaloy-clad, UO/sub 2/ plate fuel element samples demonstrated the applicability of this configuration to extended in-pile service and have shown that the factors most important in limiting the useful in-pile life of bulk UO/sub 2/ plate-type elements are in- pile operating temperature, fuel restraint, and fuel density. It was shown that the amount of fission gas released from the UO2 is increased when the fuel is subjected to excessive operating temperatures and high exposure. Microstructural changes in bulk UO/sub 2/, consisting primarily of the precipitation of both nonvolatile and volatile fission products, were noted at high exposure and high temperature, but no change in the UO/sub 2/ crystal lattice was observed. The excellent outof-pile corrosion resistance of Zircaloy cladding was conflrmed in in-pile loop tests of these samples, although, under abnormal conditions involving intentional clad defects, high coolant activity can result from corrosion of the UO/sub 2/ fuel, and accelerated corrosion of the cladding can occur. (auth)Keywords
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