Near-Optimum Shutdowns for Nuclear Reactors

The general problem of determining the optimum-power reduction function for a reactor is a complex one that depends on the desired startup time, the xenon and iodine concentrations, the variations in reactivity, and the purpose of the reactor in question. An analysis method embodied in the digital computer code SHUTDOWN makes possible the determination of near-optimum shutdown modes for most reactors. Determined functions compare favorably with available data for the Canadian NRU reactor and with solutions for the minimization of peak xenon problem found by using Pontryagin's maximum principle.