Assessment of the passive safety systems capability for KALIMER 600

A natural circulation loop has usually adopted for a Liquid Metal Reactor (LMR) because of its high reliability. Up-rating of the current KALIMER capacity requires an additional PDRC to the existing PVCS to remove its decay heat under an accident. As the system analysis code currently used for LMR in Korea does not feature a stand alone capability to simulate a closed natural circulation loop, it is not eligible to be applied to PDRC. To supplement its limitation, a model for PDRC has been developed. The incompressibility assumption for sodium enables the circuit to be modeled with a single loop flow, The developed model has then been coupled with the system analysis code, SSC-K to assess the cooling capability during unprotected accidents for the new conceptual design. As a result, the developed model has been qualified in prediction of the concerned system parameters consistently as physically intended. It is also confirmed that its application to analyses of a long term cooling has lead to a reasonable. Some thermal-hydraulic models developed during this study can be effectively applied to developments of other system analysis codes which require such component models, and the present development will also contribute to establishment of a code system for the LMR analysis