Resolution of Generic Safety Issues: Appendix C: Priority Ranking Numerical Thresholds Used in Prioritizations Completed Before June 30, 1993 ( NUREG-0933, Main Report with Supplements 1–35 )

TABLE 1 RISK THRESHOLDS

(a)	The priority rank is always HIGH when any of the following risk (or risk related) thresholds are estimated to be exceeded (or when extraordinary uncertainty suggests that they may well be exceeded):
	(1) 11000 person-rem estimated public dose per remaining reactor lifetime
	(2) 50,000 person-rem total estimated for all affected reactors for their remaining lifetime (e.g., 500 person-rem/reactor for 100 reactors)
	(3) 10-5/reactor-year large-scale core-melt
	(4) 5 x 10-4/year large-scale core-melt (total for all affected reactors)
(b)	Always at least MEDIUM priority:
	10 or more percent of the always-HIGH criteria
(c)	Always at least LOW priority:
	1 or more percent of the always-HIGH criteria
(d)	Never higher than MEDIUM priority:
	Less than 10% of the always-HIGH criteria
(e)	Never higher than LOW priority:
	Less than 1% of the always-HIGH criteria
(f)	Always DROP category:
	Less than 1% of the always-HIGH criteria

.

Parent topic: Appendices