Validation of MERCURY code under LOCA condition with Out-of-pile and In-pile tests

MERCURY is a nuclear fuel performance code based on the multidimensional finite element method developed by the Korea Atomic Energy Research Institute (KAERI). MERCURY code can be applied to the simulation of transient fuel behavior. The results of FRAPCON, which is the steady-state nuclear fuel performance code, are employed for the initial condition of the MERCURY code. In this study, code validation against out-of-pile and in-pile test data has been conducted. The validation is focused on the comparison of the temperature and deformation histories in the clad for the out-of-pile test and the final deformation shape for the in-pile test. As a results, (1) with out-of-pile test, EIGEN, it is confirmed that the simulation purpose of the MERCURY code, which is a coupled thermo-mechanical analysis code in LOCA condition, satisfies and the predicted cladding surface temperatures are very reasonable with derivation within 10% for axisymmetric behavior, (2) it was demonstrated that the simulation results by MERCURY with STUDSVIK NRC192 test showed good agreement with experimental results and (3) in case of IFA-650.5, the comparison of diameter distribution are not satisfactory because the cladding outer temperature is not properly given. It was found that the temperature profile has an important effect when large deformation occurs. In light of the points, the analysis system integrated with the thermal–hydraulic model at out of cladding is needed to better predict the ballooning phenomenon in the LOCA event.