Evaluation of ATWS core damage frequency for an earlier vintage BWR/4

In summary, this study evaluated the total core damage contribution due to ATWS events for an earlier vintage BWR/4. A realistic calculation was performed for a plant with a particular ATWS prevention and mitigation configuration and with some of the ATWS rule modifications implemented. Results are compared with the ATWS task force findings; three areas have been identified which could potentially have significant impact upon the ATWS core damage frequency contribution. 4 refs.