Post-test analyses of the CORA-15 bundle test with the system codes ATHLET-CD and SOCRAT

Analyses of the CORA-15 bundle test have been performed with the system codes ATHLET-CD (GRS) and SOCRAT (IBRAE). In the test, the behaviour of a PWR type fuel bundle, composed of 23 fuel rods and 2 absorber rods, was investigated under severe accident conditions. An important feature of the experiment different from all other CORA tests was the pressurization of fuel rods to 6.0 MPa. As a result, the fuel rods underwent ballooning and burst. In general, both codes adequately reproduced the cladding temperatures histories, the ballooning and rupture, and blockage formation due to melt relocation. The hydrogen release has been calculated within the uncertainty of the measured data.