05000348/LER-2001-002

LER-2001-002,

Docket Number
Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition
3482001002R00 - NRC Website

Westinghouse -- Pressurized Water Reactor Energy Industry Identification Codes are identified in the text as [XX]

Description of Event

During an inspection in August 1997 (report 50-348, 364 / 97-12) NRC staff reviewed silicone foam penetration seals [NF] at Farley Nuclear Plant (FNP). The report stated "The licensee was unable to locate GL 86-10 engineering evaluation documentation that evaluated the adequacy of the deviations from a tested fire barrier configuration. This does not satisfy the guidance of GL 86-10...." The NRC identified this as Inspector Follow- up Item (IFI) 50-348, 364/97-12-01.

Subsequent to the NRC inspection, Southern Nuclear Operating Company (SNC) initiated a review and evaluation of FNP silicone foam penetration seals. The result of this evaluation was that the seals under review were found to be acceptable except that further review was required for a group of penetrations that are larger than any tested configuration. Additional work was performed in an attempt to verify the acceptability of these large penetrations. Walk-downs of accessible areas were performed to identify large fire barrier seals at FNP.

These walk-downs identified a total of twenty-nine large seals for review. In early November 2000, it was noted that these seals might not meet three-hour fire barrier rating requirements. At that time fire watches were established as compensatory actions for this condition. On May 23, 2001 the evaluation was finalized by the SNC design organization and it was concluded that because of insufficient industry and test data none of the twenty- nine seals could be rated as a three-hour fire barrier. On June 20, 2001, as part of the continuing review of large seals at FNP, SNC's designers identified additional large seals that need further evaluation. Additional fire watches were established on June 20, 2001 as compensatory actions for these additional penetrations. Of these, sixteen have been subsequently determined not to meet three-hour fire barrier rating requirements.

Additional review of fire barrier penetrations in question will be completed by 180 days from the report date of this LER.

Cause of Event

The cause of this event is inadequate design in that the fire penetration seals associated with this event were designed and installed without sufficient verification of their three-hour fire barrier rating requirements.

Safety Assessment Because the fire penetration seals involved in this event have been installed without sufficient verification of their three-hour fire barrier rating requirement, their function of preventing a fire from affecting redundant trains of safe shutdown systems is not assured. Eleven of the forty-five penetration seals involved in this event are in areas for which fire watches already existed for other reasons. None of the penetrations involved in this event have been challenged during this period as no fire involving these penetrations has occurred. It is considered that fire suppression, detection and plant response along with the current barriers would provide an adequate level of protection for redundant equipment. Therefore, the health and safety of the public were unaffected by this event.

Corrective Action Appropriate fire watches for the areas involved were established on November 8, 2000 and are continuing until the condition is corrected. Additional fire watches for the seals identified on June 20, 2001 have also been established.

Review of other fire barrier penetration seals in question will be completed by 180 days from the report date of this LER.

Modifications are being planned to upgrade these seals to provide a three-hour fire barrier as is required by Appendix R. Appropriate compensatory actions will be maintained until upgrades are completed.

Additional Information

The following LERs have been submitted in the past two years related to design issues: