Beaver Valley Unit 1 and Unit 2
TS 3.7.10 requires, in part, that an adequate
Control Room Envelope (
CRE) be maintained or restored within 90 days. This protects the
CRE during postulated accident and hazardous conditions. Contrary to
TS 3.7.10, the licensee determined that an inadequate
CRE existed, due in part to a degraded (
damper corrosion) normal intake
damper, which is postulated to have existed for longer than the TS allowed time. The separate
Control Room Emergency Ventilation System (
CREVS) was not affected. The licensee identified the excessive inleakage condition during a surveillance test. The licensee had failed to to identify this component as a
CRE boundary and perform routine inspection and maintenance. Upon finding the excessive in-leakage, the licensee implemented compensatory actions to mitigate the possibility of in-leakage to the control room and completed repairs to the affected
dampers and seals. The licensee entered this issue into their corrective action program as CR 08-49260 and reviewed their
CRE maintenance program. The inspectors determined that the failure to maintain an adequate
CRE is a violation of
TS 3.7.10 identified by the licensee that affects the containment barrier cornerstone. The violation is considered of very low safety significance since it represents a degradation of the radiological barrier of the control room. This is considered a licensee-identified violation (Green),
NCV of
Technical Specification 3.7.10