Numerical simulation of mechanical interaction between pellet and zircaloy-4 cladding under reactivity-initiated accident conditions

Abstract Reactivity-initiated accident (RIA) is one of the accidents considered by fuel safety criteria. The power pulse caused abrupt expansion pellet, leading to pellet and cladding mechanical interaction (PCMI). Cladding ductility gradually decreased in process oxidation hydrogen uptake during irradiation. As a result, extrusion causes produce greater hoop stress strain, which leads damage. A simulation PCMI using ABAQUS was designed analyze mechanic properties. By comparing calculation results scheme with data obtained reactor experiment, it proved that are good agreement experimental reactor, rationality verified. Based on out-pile mandrel equipment simulated PCMI, corresponding finite element model established study related test parameters. analyzing outside found material, temperature, compression rate, tensile load, friction coefficient strain have certain relationship: (1) choice material affects reactor. overall law stress-strain external basically has no effect. (2) temperature effect peak. (3) rate time for reach peak stress. (4) Tensile load will affect starting position cladding. (5) significant influence trend experiment can be carried out more effectively, provide guidance basis experiment.