During a Large Break Loss-Of-Coolant (LBLOCA) accident, ballooning of the fuel rod claddings may occur in Light Water Reactors. Computational models, based on the usual 'representative pin', are unable to predict the absence of significant blockages as otherwise observed in experiments studying post-LOCA reflood. The new computational tool MATARE (MAbel-TAlink-RElap) for multi-pin deformation analysis, created through the dynamic coupling between the thermal-hydraulic code RELAP5 and multiple instances of the single-pin thermal-mechanics code MABEL, is able to deal with distinct fuel rods into the thermal-hydraulic model of the reflood. As part of MATARE validation efforts, the code has been evaluated against experimental data from the MT-3 test performed in the NRU reactor at Chalk River. The MT-3 experiment utilized a test array of 32 rods, of which 12 pressurised, to simulate PWR fuel bundle behaviour under reflood conditions, providing an excellent database to assess the capabilities of the code. Benchmarks performed included cladding temperatures, rupture locations and orientations, burst strain ranges, axial rod profiles and rupture times. MATARE reproduced the experimental results with good prediction error. In particular, the code was able to calculate a substantial incoherent ballooning in agreement with the experimental data.

AMMIRABILE Luca;  WALKER Simon; 

2009-11-13

Atomic Energy Society of Japan

JRC52440

https://publications.jrc.ec.europa.eu/repository/handle/JRC52440,