Mitsubishi Heavy Industries (MHI) developed the SPARKLE-2 code, which is a coupling of the PWR system transient analysis code M-RELAP5, the 3D neutron kinetics code COSMO-K, and the 3D core thermal-hydraulics code MIDAC. MHI validated the coupling calculation, including data transfer and the total reactor coolant system response, with the OECD/NEA MSLB benchmark problem. This benchmark problem has been used to verify coupled codes developed and used by many organizations. The calculation results of the SPARKLE-2 code indicate good agreement with other benchmark participants’ results.
MHI has performed a study of the applicability of the SPARKLE-2 code to the rod ejection and main steam line break events which are representative non-loss of coolant accident (non-LOCA) events which accompany dynamic changes in local core parameters. The results of the evaluation are compared with the current US-APWR DCD [1] case. The results have shown that the current analyses described in the US-APWR DCD are sufficiently conservative and hence this verifies that the US-APWR reactor design contains sufficient thermal margins.
