A computer program was developed for performing thermal hydraulic transient analysis of nuclear power plant containment buildings. The code package includes pre- and post-processors that facilitate the development of compartmental node models for the analysis of a variety of thermal hydraulic problems. This program was used on the analysis of thermal transients resulting from the postulated failure of all ventilation fans in the river intake pump house (housing eight 662 kW (700 hp) and eight 932 kW (1250 hp) pumps) at a nuclear power plant. This paper describes the development of a model for the structure and application of temperature transients resulting from ventilation fan failure under varying outside air conditions. The analysis included the response of the building fire protection system in mitigating the temperature transient. Through utilisation of this model, transient natural convection analysis of several temperature excursions were rapidly developed.

KEYWORDS: rooms, air flow, natural ventilation, computer programs, calculating, nuclear reactors.