Assessment of ice-condenser containment performance issues

Containment performance plays a dominant role in the assessment of risk associated with severe accidents. The primary concerns for containment performance are how well the containment can withstand the pressure and temperature loads associated with severe core damage accidents and whether or not the containment is bypassed. The objective of this paper is to summarize an issue characterization study performed by Brookhaven National Laboratory for an ice-condenser containment during severe accidents. This study was the first to focus in a coordinated way on the challenges and improvements relevant to an ice-condenser containment and provides a comprehensive statement of the relevant issues that can be used in the US Nuclear Regulatory Commission (NRC) staff's evaluation processes and by utilities during their individual plant examinations. The types of pressurized water reactor ice-condenser containment challenges that have been identified in past probabilistic risk assessments, including the second draft of the NUREG-1150 risk analysis for Sequoyah, are summarized and arranged according to the containment function objectives they threaten. A list of proposed potential improvements for an ice-condenser containment is given.