Conceptual design and analysis of a semi-passive containment cooling system for a large concrete containment

An internal evaporator-only (IEO) concept has been developed as a semi-pass ive containment cooling system for a large dry concrete containment. The fu nction of this system is to keep the containment integrity by maintaining t he internal pressure not to exceed ultimate design pressure, i.e. 0.83 MPa (120 psia) in the absence of any other containment cooling following a seve re accident, which postulates core damage and hydrogen combustion. The abil ity of the concept to protect the containment was evaluated for the design basis accident (DBA) large break loss of coolant accident (LB LOCA) and sev ere accident scenarios (LB LOCA without Emergency Core Cooling System (ECCS ) and containment spray flow, 100% zirconium oxidation and complete hydroge n combustion). All were modeled using the GOTHIC computer code. It was conc luded that a practical system requiring four IEO loops could be utilized to meet design criteria for severe accident scenarios. (C) 2000 Elsevier Scie nce S.A. All rights reserved.