05000280/LER-2010-002
| Nocket Ni Imrffr Sequential Rev | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition |
| 2802010002R00 - NRC Website | |
1.0 DESCRIPTION OF THE EVENT The Surry NRC Triennial Fire Protection Inspection was initiated on June 8, 2009.
During performance of the inspection, the NRC inspectors requested documentation that aluminum conduits used for Appendix R wall and floor fire barrier penetrations seals [El IS-IC-PEN] were qualified to a 3-hour fire rating. Documentation was available for steel conduits, steel cable trays, and aluminum cable trays that penetrate fire barriers. Test reports were not available for the aluminum' cond uit penetrations. The concern was that the aluminum conduit would melt at the flame temperature used during fire testing and if not properly sealed internally, flame and smoke may pass through the barrier.
The Surry specification for the installation, inspection, and documentation of silicone foam in fire barrier penetrations was issued in 1978 and provided guidance for foam installation. It requires that all conduits that penetrate the control room pressure envelope or penetrate fire area boundaries and terminate at a distance up to 5 feet from the barrier are to be foamed internally. Also, station electrical maintenance procedures for opening and sealing of fire barriers required that conduits be internally foamed to a depth of 10 inches with at least part of the foam contained within the wall or floor. The internal foam would provide a seal to prevent passage of hot gasses and smoke through the penetration in the event of an Appendix R fire.
Conduit penetrations foamed internally to these requirements were consideired acceptable.
In 1990 and 1991, Surry developed a Fire Penetration Seal Evaluation Program in response to Information Notice (IN) 88-04 and IN 88-04 Supplement 1, Inadequate Qualification and Documentation of Fire Barrier Penetration Seals. The numbers of penetrations not meeting the 3-hour fire rating were identified and repairs recommended. The scope of the program included identification and repair of conduit internal seals. Repairs were completed during unit outages in 1994.
However, the documentation for these repairs was not adequate to ensure compliance with the 3-hour fire rating for aluminum conduit penetrations.
Following the 2009 Triennial Fire Protection Inspection, a condition report was initiated and corrective actions were assigned to establish a valid qualification package for the aluminum conduit penetration configurations. A walkdown of accessible penetration areas (approximately 90% of penetrations) was conducted and an evaluation of drawings was performed to determine the various configurations where aluminum conduits penetrate fire barriers. Approximately 460 aluminum conduit penetrations were identified for both Surry Unit 1 and Unit 2. Three aluminum conduit configurations were identified and an evaluation determined the internal foam installation on two of the configurations may not be adequate. These fire barriers were declared non-functional and a condition report was initiated