TOKRAC: a computer code system for real-time PWR accident tracking simulator or program

TOKRAC is a computer code system which aims at being implemented into a real-time accident tracking simulator for reactor coolant system of a PWR plant. The accident tracking simulator is to be so designed as to trace and scrutinize in real-time the off-normal conditions of the troubled plant with the prompt and positive use of plant instrumentation signals, and the fast-running computer program such as TOKRAC will be used to simulate the thermohydraulic behavior of nuclear power plant during accident. For the convenience of the usage of TOKRAC program, described are, (i) details of mathematical models and numerical methods employed in TOKRAC on primary loop fluid dynamics, heat generation and heat transfer in the reactor core, various component models such as pump, pressurizer, steam generator, emergency core cooling system, and special models of water level and critical flow, (ii) overview of whole code system including graphic processing, and (iii) explanation of data setup for program execution for a sample problem. (author)