Analysis of the NUPEC PSBT tests with FLICA-OVAP. Part 1: void distribution benchmark

Based on NUPEC PWR Subchannel and Bundle Tests (PSBT), an international benchmark has been promoted by OECD and NRC and has been coordinated by Penn State University (PSU). The benchmark includes void distribution and departure from nucleate boiling exercises. This paper is aimed at illustrating the capabilities of the full 3D thermal-hydraulic code FLICA-OVAP in predicting void distribution measurements available by the NUPEC tests. Subchannel and bundle test configurations have been analyzed. Both steady-state and transient scenarios have been addressed, including power increase, flow reduction, temperature increase and depressurization, representative of PWR thermal-hydraulics conditions. After a brief description of the main features of FLICA-OVAP, the relevant physical models available within the code are detailed. Results obtained in the different tests included in the PSBT void distribution benchmark are therefore reported. The relevant role of selected physical models is discussed. (author)