Estimation of Differential Pressure Loadings Across R.B. Internal Structures of 500 MWe PHWR Containment

Abstract

500 MWe PHWR containment adopts vapour suppression system for reduction of over pressures following LOCA or steam line break. The reactor building is internally subdivided into number of rooms and floors housing different equipment and systems, which segregate the active areas from non-active areas. Further, the design of suppression pool system calls for complete separation of areas, containing high pressure, high temperature fluid system from the rest of the areas of reactor building. During normal reactor operation, separation of different areas (rooms) is required from the consideration of activity spreading from active areas to non-active areas. However, during accident conditions, such as LOCA or steam line break, large differential pressures will result across the walls and floors of the break compartment unless the rooms within volume V1 and that within V2 are well communicated. Analyses have been carried out to evaluate the differential pressures across reactor building internal floors and walls using a computer code 'SUBCOMP'. In this paper some of the important features of the computer code 'SUBCOMP' are described. The results of the analyses showing the differential pressures across R.B. internals that are required to be considered in design, are also presented.