| Abstract: | A quantitative evaluation of primary containment venting was performed to assess its risk reduction potential. A boiling water reactor with a Mark I containment was evaluated by developing simplified containment event trees for its risk dominant sequences. Risk results were benchmarked with those from the NUREG-1150 risk rebaselining effort, and sensitivity studies then were performed. It was found that for station blackout sequences, containment venting by itself does not significantly reduce overall risk. For sequences involving loss of long-term decay heat removal or failure to scram, however, venting is potentially an important mechanism in preventing or delaying core melting. Subsequent studies show that when venting is combined with other potential containment improvements, there is a large potential for risk reduction. |
