05000237/FIN-2008004-04
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Finding | |
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| Title | Licensee-Identified Violation |
| Description | On May 23, 2008, the licensee identified that a flexible connector was disconnected on a Halon bottle for the Auxiliary Electrical Equipment Room (AEER) fire suppression system. The licensee concluded that the halon system was last worked on April 24, 2008, under WO 01083261-01, Perform DFPS 4195-01, Halon System Operability, and the system connections were not properly tightened. This was a violation of TS 5.4.1. The licensee declared the system inoperable, reconnected the flexible connector thereby restoring operability, and placed the issue into their corrective action system in IR 779061, AEER Halon Pilot Hose Not Connected. The licensee performed a prompt investigation and a human performance investigation of the incident in addition to reviewing historic operability. The inspectors reviewed the licensees assessment of the functional impact of the disconnection upon the Halon system. The flexible connector from the solenoid pilot valve to port B of the manual-pneumatic actuator was disconnected at the solenoid pilot valve for the #1 pilot bottle for the initial discharge bank of Halon bottles. The disconnection would have prevented actuation of the solenoid pilot valve for the #1 pilot bottle from pressurizing the pilot manifold. (Manual actuation using the pull lever on the bottle would not have been affected.) The Halon system had two pilot bottles for initial discharge bank and the redundant pilot bottle was not affected. Consequently, upon receiving a signal to discharge, the redundant pilot bottle would have pressurized the pilot manifold line resulting in the contents of the all of the Halon bottles within the initial discharge bank being discharged. The licensee evaluated the potential for back leakage through the disconnected flexible connector depressurizing the pilot manifold line. The inspectors concurred with the licensees assessment that reduction in pressure of the pilot line due to the disconnection would have been minimal and that discharge of the Halon bottles (due to actuation of the redundant pilot cylinder) would not have been prevented. The inspectors noted that the back leakage flow path had a 1/32 inch restriction in comparison to the 3/16 inch flexible connectors used for pressurizing the pilot manifold. In accordance with IMC 0609, Significance Determination Process, Attachment 0609.04, Phase 1 - Initial Screening and Characterization of Findings, Table 3b the inspectors determined the disconnection degraded the fire protection defense-in-depth strategies. Therefore, screening under IMC 0609, Appendix F, Fire Protection Significance Determination Process, was required. The inspectors concluded that the disconnection represented a low degradation because, although there would have been a loss of redundancy, the Halon system would have functioned. As such, the issue screened to Green under Task 1.3.1, Step 1, of IMC 0609. |
| Site: | Dresden  |
|---|---|
| Report | IR 05000237/2008004 Section 4OA7 |
| Date counted | Sep 30, 2008 (2008Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | D Melendez-Colon W Slawinski C Phillips M Phalen D Lords E Coffman B Cushman J Draper |
| INPO aspect | |
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Finding - Dresden - IR 05000237/2008004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Dresden) @ 2008Q3
Self-Identified List (Dresden)
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