Study on diagnostic plant analyzer method for support of emergency operation

Methods of time-critical diagnostic plant analyzer are investigated which would serve as support to emergency operation of nuclear power plant. A faster-than-real-time simulator code TOKRAC is developed for analyzing PWR primary loop thermo-hydraulics of small-break LOCA and it is applied for a numerical experiment of initial phase of TMI-2 accident. TOKRAC resulted in a good agreement with a RELAP4/MOD6 calculation and the plant record with as fast as can one-tenth of real time. A real-time estimator of SG heat transfer rate based on Kalman filter is proposed and its applicability is verified using LOFT ATWS experimental data. With regards to how to integrate those methods into the software system in operation support center, a new concept of module-based simulation system is proposed which aims at offering a flexible and human-cognitive oriented environment for various analytical tool development