INTEG INSPEC, Accident Frequencies and Safety Analysis for Nuclear Power Plant

1 - Description of problem or function: These programs analyze the characteristics of a general model developed to represent the safety aspects of an operating nuclear reactor. These characteristics are the frequencies of incidents that are departures from the expected behavior of the reactor. Each incident is assumed to be preceded by a sequence of events starting at some initiating event. At each member in this sequence there may be functions such as safety circuits, and personnel operations that stop the sequence at that member. When mechanical devices fail they are assumed to remain inoperative until repaired. The model accounts for scheduled inspection and maintenance of all equipment in the system. 2 - Method of solution: In INTEG, the discontinuous density function is integrated by the trapezoidal rule from time equals zero to time equals t. INSPEC is based on the simulation of reactor operation as a Markov process. A vector of probabilities is successively multiplied by a transition matrix. 3 - Restrictions on the complexity of the problem: INSPEC is limited to subsystems with no more than 7 safety circuits. The transition matrix can be made up as desired so that any intercorrelations between failures of circuits can be accommodated. In INTEG, failure rates of safety circuits are restricted to independence