LOCA scenario tests of irradiated fuel rod specimens

Safety analysis for loss-of-coolant-accidents (LOCAs) involves assessment of the embrittlement of the cladding and of fuel assembly flow accounting for cladding ballooning. The NRC's cladding performance program at Argonne National Laboratory (ANL ) is investigating embrittlement and ballooning of high-burnup fuel rod segments in out-of-reactor laboratory tests. The integral tests are being closely coordinated with the LOCA transient tests being performed in Halden's IFA-650 rig. The ANL tests are being conducted with high-burnup 30-cm segments from Limerick (9 · 9 Zircaloy -2) and H.B.Robinson (15 · 15 Zircaloy -4) reactors. Results from tests on the BWR segments were presented at the Sandefjord meeting. The tests on the PWR segments will be conducted this Fall. Embrittlement is being studied with ring-compression tests on irradiated and unirradiated specimens of Zircaloy-2 , Zircaloy-4, ZIRLO (trademark) and M5 (trademark) cladding. Limited testing has also been done on unirradiated specimens of E 110 cladding and prehydrided Zircaloy-4 cladding. Steam oxidation temperatures ranged from 10 00 -12 00 C, which covers the range of interest for safety analyses. The ring-compression tests were performed at room temperature and 135 C, which is the coolant saturation temperature following core quenching and has regulatory precedence. (Author)