Simulation of Cold Leg Manifold Break and Station Blackout Revised Sequences for Reduced ECCS (Emergency Core Cooling System) in the N Reactor.

摘要

This report presents analyses of two loss-of-coolant-accident sequences of the N Reactor using the RELAPS/MOD2 computer code. RELAP5/MOD2 is a best estimate, two phase, nonhomogeneous, nonequilibrium, thermal-hydraulic, computer code designed for light water pressurized reactor transient. The N Reactor is a graphite- moderated, pressurized water reactor. The primary coolant is channeled through 1003 horizontal pressure tubes which contain two concentric tubular metallic fuel elements. The two accident sequences simulated were a double-ended guillotine break in the cold leg manifold and a station blackout. Both simulations cover the period beginning with the initiating event, either the break or the loss of ac power, to the stabilization of the core fuel element temperatures. (The station blackout calculation was carried out until the core was quenched.) The discussion presented in this report includes brief descriptions of the N Reactor, of the computer code and specific code modifications for horizontal reflood, and the computer code model used for the simulation. This discussion also presents the results and the analyses of the two calculations. (ERA citation 13:048625)