Unreviewed Safety Question (USQ)

A situation where:

a. the probability of the occurrence or the consequences of an accident or the malfunction of equipment important to safety previously evaluated in the Documented Safety Analysis could be increased;

b. the possibility of an accident or malfunction of a different type than any evaluated previously in the documented safety analysis could be created;

c. a margin of safety could be reduced; or

d. the documented safety analysis may not be bounding or may be otherwise inadequate. (10 CFR Section 830.3)

a. A USQ exists if one or more of the following conditions is identified:

(1) the probability of occurrence or the consequences of an accident or malfunction of equipment important to safety as previously evaluated in the facility safety analyses could be increased;

(2) the possibility for an accident or malfunction of a different type than any evaluated previously in the facility safety analyses could be created; or

(3) any margin of safety as defined in the bases of the TSRs could be reduced.

b. A USQ determination is made when one of the following circumstances occurs:

(1) temporary or permanent changes in the facility as described in existing safety analyses;

(2) temporary or permanent changes in the procedures as derived from existing safety analyses; and

(3) tests or experiments not described in existing safety analyses.