Technical specification 6.8.1.e requires that written procedures covering the
Fire Protection Program shall be properly implemented. Procedure AP-1038,
Fire Protection Program, establishes
TMI Unit 1
Fire Protection Program functions. Procedure 1303-12.9,
Fire Barrier Seal Inspection, requires that penetration seals be verified functional to ensure compliance with procedure 1038. Contrary to these requirements, inspections of the fire seals for the five safety-related 120 volt vital inverters were not performed. In addition, fire seal inspections performed in July2008 as part of prior extent-of-condition reviews for multiple degraded fire seals (IR793088 and Green
NCV 05000289/2008-004-01), did not identify two degraded fire seals for vital inverters \'C\' and \'E\' and did not initiate corrective measures. Consequently, the seals which were damaged during inverter replacement activities in November 2007, did not meet the required
3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire rating for a period of two years. However, engineers determined the degraded fire seals would have provided at least a one hour fire rating and due to defense-in-depth the degraded fire seals would not have affected operability of the vital inverters in the event of a fire. This finding adversely affected the reliability of equipment required to achieve and maintain a
safe shutdown condition following a severe fire, because the degraded fire seals adversely affected the confinement defense-in-depth element of fire protection. The finding is greater than minor because it is associated with the protection against external factors attribute of the
Mitigating Systems cornerstone. This finding is of very low safety significance because the
safe shutdown of the plant was not affected due to available defense-in-depth fire protection features such as incipient and ionization detectors, control room alarms, the plant\'s fire brigade team, and also because the degraded seals would have provided greater than a
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> fire rating protection in the event of a fire. This issue was placed in Exelon\'s corrective action program as IR 995903. Corrective actions included extent-of-condition walkdowns, repair of the fire seals, and ensuring these seals are inspected every two years.
