DROP-WEIGHT RING COMPRESSION TEST FOR EVALUATING THE MECHANICAL BEHAVIOR OF FUEL RODS UNDER IMPACT CONDITIONS

Several static and dynamic tests have been proposed to assess impact behaviour of spent fuel cladding. For example, the three-point bending test was used to simulate the loading conditions during a 9m-lateral regulatory drop test. The ring compression test has been chosen by several laboratories as a tool to assess cladding mechanical properties as well, though not under dynamic loading conditions. The main advantage of this test is its simplicity. However, strain rates representative of impact loading cannot be attained with conventional testing machines. To this end, a drop-weight tower was used to perform ring compression tests. This test intended to simulate the pinch forces generated in the contact between the cladding and the spacer grid under hypothetical transport accident conditions. The aim of this work is to examine the possibilities that the drop-weight ring compression test can offer for the evaluation of cladding response under impact conditions. For that purpose, a comparison between results obtained in both dynamic (i.e. drop-weight tests) and quasi-static (i.e. conventional testing machines) ring compression tests was made.