Simulating the Power Rundown Transient from Poison 96 Injection System for a CANDU Reactor

Abstract

CANDU reactors have two independent, diverse, and physically separated shutdown systems. The second shutdown system operates by injecting a neutron absorbing poison solution into the moderator. The reactivity and power rundown transients resulting from poison injection are simulated using a series of hydraulics and reactor physics codes. This paper deals with the development and validation of the reactor physics component of this simulation model. Experimental power rundown transients from the Bruce NGS A and Bruce NGS B reactors are compared with those simulated with the model described in the paper. Agreement is found to be good.