The design and evaluation of a passively cooled containment for a high-rating pressurized water reactor

An integrated pressurized water reactor (PWR) containment was conceptualize d that allows heat to be rejected passively to the environment. The propose d containment is based on the demonstrated Ebasco Waterford 3 design. The s econdary concrete shell was equipped with inlet and outlet Vents that creat e an air-convection annulus. These vents also permit the submersion of the lower part of the primary containment into an external water pool. An inter nal water pool located at the bottom of the lower containment was added to increase in-containment heat storage. The performance of the proposed passi vely cooled containment was evaluated using a subdivided volume code, GOTHI C version 3.4e; the relative novelty of subdivided Volume analyses for cont ainment performance evaluation requires experimental verification of princi pal code predictions. Two experiments were carried out; one to test the per formance of the external moat, and one to verify the code's ability to pred ict thermal-stratification inside the containment. To improve the subdivide d-volume simulation of convection-related parameters, a modeling technique (boundary layer flow approximation) was devised. Finally, the behavior of t he proposed containment was evaluated for the worst-case large break loss o f coolant accident and the worst-case main steam line break accident. Peak pressures remained below 0.45 MPa during both transients; internal wall pre ssure differences, equipment qualification temperatures, pressure restorati on time also remained below design limits. The mitigation capability of hyd rogen recombiners was also evaluated. (C) 2000 Published by Elsevier Scienc e S.A. All rights reserved.