ATWS: a reappraisal. Part II. Evaluation of societal risks due to reactor protection system failure. Vol. 4. The probability of exceeding 10CFR100 guidelines from ATWS events in light water reactors

This is the fourth and final volume of Part II of this series of studies. The three earlier volumes of Part II considered the fraction of total potential risk attributable to ATWS (measured in REM, 30 day whole body dose). This analysis was based upon the methods of WASH 1400. The results obtained there showed that ATWS is responsible for less than 5 percent of the total LWR risk. This fourth volume considers the probability of an ATWS releasing sufficient radiation so as to violate the radiation limits set by 10CFR100. Calculations show that the probability is less than 3 x 10/sup -7/ per year (3 chances in 10 million). Since WASH 1270 stated that a desirable probability would be on the order of 10/sup -7/ per year, it would appear that such a limit has already been met.