Ya. K. KOZMENKOV, Yu. I. OREKHOV Institute of Physics and Power Engineering, Obninsk, Kuluga Region,

Russian Federation

Abstract

LOCA initiated by a guillotine break of the pressurizer surge line has been considered in the paper. The failure of two emergency core cooling system (ECCS) trains was also postulated, that turns the considered accident sequence into a beyond the design basis (BDB) class. Basic design characteristics of the ABV reactor and the containment system are presented as well as the factors of much importance to the accident progression.

SCDAP/RELAP5/MOD3.1 was used as the computer code for the simulation of reactor and containment system behavior in the course of the accident. Since a noncondensable driven pressurizing system was employed in the reactor design, the presence of dissolved nitrogen in the primary water was taken into account in calculations.

The important feature of the simulated accident is the primary system refilling with the water of pressure suppression pool driven by the pressure difference between containment system compartments.