Benchmark of GOTHIC to EBR-II SHRT-17 and SHRT-45R Tests

GOTHIC™ has been used to simulate the Experimental Breeder Reactor–II (EBR-II) Shutdown Heat Removal Test 17 (SHRT-17) and Shutdown Heat Removal Test 45R (SHRT-45R), which correspond to protected and unprotected loss-of-flow events, respectively. GOTHIC is a versatile general-purpose, thermal-hydraulic software package that is a hybrid between traditional system thermal-hydraulic and computational fluid dynamics codes. It is a practical engineering tool that has been used for the design and licensing of existing plants, small modular reactors (SMRs), and next-generation plant designs. Historically, the software has been applied for containment analysis and operability assessments for light water reactors (LWRs), but the recent improvements included in GOTHIC 8.3(QA) allow for the software to be used to simulate advanced, non-LWR concepts currently being developed such as sodium, molten salt, lead, and gas–cooled designs.

It will be demonstrated in this paper that GOTHIC includes both the required attributes to model EBR-II and the appropriate physics to accurately simulate the steady-state operating conditions as well as SHRT-17 and SHRT-45R. The GOTHIC model of EBR-II was developed using only publicly available information. The nodalization was selected not only to capture the important phenomena but also to remain computationally efficient. The GOTHIC results show good agreement in both magnitude and trend with the experimental data. Differences are within the bounds of experimental uncertainty and required engineering assumptions applied in the model to fill in gaps in information, particularly for the various leakage paths that existed throughout the primary side of EBR-II, and were not well characterized during the tests.