Determination of pressure carrying capability of the containment structural system for the Mark III standard plant

As a result of a study of the Three Mile Esland event, and concerns expressed regarding hydrogen control and containment integrity, there is a need to know the capability of the Mark III containment structural system of the current Boiling Water Reactor (BWR) Standard Plant in resisting potentially-high pressure associated with severe but improbable accidents. This paper presents the assessment performed at General Electric to determine the maximum pressure at which the Mark III Containment Structural System can be expected to maintain its integrity. The assessment shows that the pressure that may cause loss of containment integrity at the dome/knuckle region is conservatively calculated to be 58.5 psig which is about four times the design pressure. (orig.)