Experiments on transient fuel failure mechanisms: selected ANL programs

Some of the experimental work related to understanding of fuel failure mechanisms under transient conditions performed at Argonne National Laboratory is reviewed in this paper. Both in-reactor and laboratory tests are considered. The range of tests discussed includes measurements of fuel properties needed in analytical work, laboratory studies of the response of fuel subjected to temperature transients by direct-electrical-heating (DEH) techniques, and laboratory experiments on cladding failure under transient heating conditions. In-reactor tests conducted in TREAT are also discussed, including the E- and H-series transient overpower accident simulations, the L- and R-series loss-of-flow accident simulations. In addition to completed tests, needs for future experiments directed at model verification and integral tests of failure threshold are discussed. This testing is directly applicable to development and verification of analytic models of fuel behavior and of fuel pin failure. Larger scale tests are also reviewed as these experiments provide the ultimate test of the ability of predictive techniques to represent events in a realistically sized pin bundle. (U.S.).