高速炉プラント動特性解析コードSuper-COPDによるFFTF LOFWOS No.13試験のベンチマーク解析

抄録

A plant dynamic analysis code named Super-COPD have been developing for safety and design studies of a sodiumcooled fast reactor. Validation of the plant analysis model including neutronics calculation of a one-point reactor kinetics model against experimental data necessitates the further work on the beyond design basis accident to improve the prediction accuracy. Therefore, Japan Atomic Energy Agency participated in International Atomic Energy Agency (IAEA) benchmark for Loss of Flow without Scram (LOFWOS) test No.13 performed at the Fast Flux Test Facility (FFTF) as one of the passive safety demonstration tests. The transient analysis considering with major reactivity feedback mechanisms was carried out with the Super-COPD and the results at the first blind analysis phase of the benchmark project were assessed against the measured data. It was observed that the whole plant dynamics analysis by the SuperCOPD could follow the measured data and the analysis model had the prospect of applicability to the LOFWOS event in the beyond design basis accident. However, discrepancies were still observed in the outlet sodium temperature profile of two fast-response proximity instrumented open test assemblies (PIOTAs) in the natural circulation conditions. As a future work, the core model will be refined to improve the prediction accuracy of radial heat transfer rate.