A nuclear criticality simulator

A computer-based nuclear criticality simulator has been developed for use in nuclear criticality safety training at Rockwell International's Rocky Flats plant. This device simulates the behaviour of a wide variety of configurations or assemblies of fissile and nonfissile materials and conditions. The use of this simulator in training is designed to motivate viewers to be safe and deliberate in their actions concerning fissile materials; to illustrate the parameters that may affect criticality; and to show how people and equipment might be affected in a typical criticality incident. The project comprises a computer portion, consisting of a microcomputer and BASIC software that uses Monte Carlo techniques to model each situation; an input/output system that reads the current status of the simulation and outputs the implications of this state to various devices such as video and audio counters, criticality alarms, a blue flash and beacons; and a mechanical portion, consisting of realistic fissile material, support framework and table, drive motors and pumps, etc. The system is able to simulate situations involving the movement of solid pieces or clusters of material, the pouring or pumping of powders and liquids, and the movement of a human hand near the assembly. Emphasis has been given to generic situations which illustrate the influence of mass, shape, moderation, reflection, and interaction on criticality. Experience with the simulator has been quite positive, showing a high degree of viewer interest and involvement