Development of Core Technology of PHWR Safety Enhancement and Evaluation

By developing CANDU technologies for detailed evaluation and treatment of aging, core physics/severe accident(SA), moderator issues in order to fortify safety in Wolsong plants: Development of aging evaluation model for Wolsong pressure tube (PT) as a key technology to PHWR safety margin enhancement. Establishment of evaluation and management system for recent issues in PHWR core physics and SA that would be equivalent to the PWR system. 3-dimensional PHWR moderator circulation experiment for code validation The following concrete results are obtained from this research. - Development of diameter prediction model for the irradiated PT - Development of localized analysis system for PHWR core and evaluation of positive reactivity in Wolsong LOCA - Development of world-class ISAAC engine, simulator and construction of evaluation DB for domestic critical issues from Fukushima post actions - Development of SAMG decision-supporting system (SAMEX-CANDU) for using accident management and prediction under ultimate accidents - Construction of the PHWR moderator circulation test (MCT) facility, steady state experiment and CFD validation analysis The following two main effects are expected from this research. - (1) PT aging evaluation technology could increase the level of safety margin, (2) PT core physics and SA evaluation technology could be a basis for enhancing safety and ultimate accident managing capability, and (3) both help to clear PHWR safety issues including those of continued operation in Wolsong - The optimal SAM decision-support technology (which is world-leading technology in PHWR) could be an effective advisory tool for emergency preparedness and TSC staff's decision under severe accidents of Wolsong NPP (for example, AtomCARE) - The MCT results can be used to develop a domestic CFD code which can replace MODTURC_CLAS which was used for the safety analyses of Wolsong Unit 1 refurbishment and 37M fuel safety analysis for moderator circulation.