Study of hydrogen combustion and containment building response at Ringhals Nuclear Power Plant Unit No. 3

This paper gives a brief description and some results of the work performed at the Swedish State Power Board for Ringhals Unit 3 PWR in the area of hydrogen combustion and containment structure response to resulting loadings. Calculations were carried out of: containment building static failure pressure using MARC finite element code and other methods, deflagration of homogeneously distributed hydrogen and local detonation with structure response using PISCES-2DELK code. The main conclusions are as follows: (1) static absolute failure pressure for the building is about 0.75 MPa; (2) the containment structure can withstand loads due to deflagration of hydrogen resulting from the reaction of up to about 85 percent of fuel cladding with water (100 percent reaction gives 830 kg H2); and (3) the containment structure has a capability to withstand the loads due to the local detonation of the relatively large amount of hydrogen (200 to 300 kg)