05000237/FIN-2009002-09
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Finding | |
|---|---|
| Title | Licensee-Identified Violation |
| Description | The Licenses for Units 2 and 3 require that the licensee follow their fire protection program. Fire protection program requirements are identified in the Technical Requirement Manual. Technical Requirements Manual, Section 3.7.k, Condition B, states in part that the Auxiliary Electrical Equipment Room (AEER) halon system, including the extended discharge cylinders shall be operable and if not then a dedicated fire watch shall be established within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. Contrary to the above, on October 29, 2008, the licensee identified that all of the AEER halon fire suppression extended discharge cylinders were completely discharged. The licensee concluded that the cylinders had been in this condition since October 23, 2008, based on a trend recording of a downward spike in room temperature caused by the discharge. The inspectors and the NRC Region III senior reactor analyst (SRA) used IMC 0609 Appendix F, Fire Protection Significance Determination Process to evaluate the significance of the finding. The finding category of Fixed Fire Protection Systems was assigned because the function of the automatic Halon suppression system for the AEER was degraded. Since only the extended release portion of the system was affected and the initial release was fully functional, a moderate degradation rating for the finding was used. The NRC assumed that the design concentration could be achieved but could not be maintained for sufficient time to ensure fire extinguishment. The condition existed for 6 days. The Significance Determination Process (SDP) uses a generic duration factor of 0.1 if the duration of the degradation is between 3 and 30 days. Since the exact duration was known to be 6 days, the SRA calculated an actual duration factor of 0.016 (6/365 days). The generic fire area frequency for a cable spreading room with other electrical equipment is 6.0E-3/yr. The change in Core Damage Frequency (CDF) calculated in the phase 1 SDP is determined by multiplying the duration factor by the generic fire area frequency which is estimated to be 9.6E-5/yr. Since this value is greater than 1E-5, the screening criterion for moderate degradation findings, a phase 2 evaluation was required. In step 2.1 of the SDP, the identified safe shutdown path for a fire in the AEER was evaluated. Because the finding does not affect the safe shutdown path, it can be credited. After reviewing the licensees safe shutdown analysis, the SRA determined that safe shutdown after a fire in the AEER would require local operator actions. Therefore, a safe shutdown unavailability factor of 0.1 was applied. The delta CDF was recalculated by multiplying the duration factor, fire frequency, and safe shutdown path unavailability factor and was determined to be 9.6E-6/yr. This result was conservative because it does not include any credit for manual fire suppression using the installed carbon dioxide system which was unaffected by the finding. Since this delta CDF was less than the screening criterion of 1E-5, the finding was determined to be of very low safety significance and screened to Green in step 2.1.4. The inspectors had no issues with the licensees corrective actions and determined that they were completed or had an acceptable time table for completion |
| Site: | Dresden  |
|---|---|
| Report | IR 05000237/2009002 Section 4OA7 |
| Date counted | Mar 31, 2009 (2009Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | D Melendez-Colon W Slawinski C Phillips M Ring E Coffman J Draper |
| INPO aspect | |
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Finding - Dresden - IR 05000237/2009002 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Dresden) @ 2009Q1
Self-Identified List (Dresden)
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