ENS 41714
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ENS Event | |
|---|---|
22:50 May 18, 2005 | |
| Title | Identification of Design and Operating Procedure Deficiencies Related to Appendix R Events |
| Event Description | During a review of the dedicated shutdown procedure (20.000.18), several possible design and operating procedure deficiencies were identified affecting Appendix R events. BOP Battery Charger 2C-1 is relied upon to feed post fire emergency shutdown loads. It was determined that although a circuit breaker supplying power to battery charger 2C-1 was re-closed by procedure, an additional action was required to place the battery charger in service. The BOP battery charger 2C-1 contactor circuit logic requires the control switch first be returned to the off-reset position, before the contactor can be re-energized. That control switch and associated control wiring is located in the control room envelope that is evacuated in an Appendix R fire scenario. Furthermore, the dedicated shutdown logic does not isolate this control switch circuitry from cables in the fire affected zone which is a requirement of the Appendix R circuit design.
In addition to the same issues identified for battery charger 2C-1, it was determined that the dedicated shutdown procedure did not provide for closure of the circuit breaker feeding power to battery charger 2C1-2. Battery charger 2C1-2 is required to power 260VDC motor operated valves used by the standby feedwater system to provide reactor cooling water and to control reactor water level after a shutdown due to an Appendix R fire. For both of these problems, power would be initially supplied by the associated batteries, but the batteries are not sized to provide power for the entire duration of the Appendix-R event. Therefore, when the plant must be shutdown from outside of the control room, a safe shutdown cannot be assured using the dedicated shutdown panel. This event is being reported as an unanalyzed condition under 50.72(b)(3)(ii)(B). The affected Appendix R equipment was declared inoperable, and procedure changes to address this issue are being considered to address these conditions. The NRC Resident Inspector has been notified. |
| Where | |
|---|---|
Fermi  Michigan (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| LER: | 05000341/LER-2005-003 |
| Time - Person (Reporting Time:+-3.38 h-0.141 days <br />-0.0201 weeks <br />-0.00463 months <br />) | |
| Opened: | Scott Bahnsen 19:27 May 18, 2005 |
| NRC Officer: | Bill Huffman |
| Last Updated: | May 18, 2005 |
| 41714 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 552312021-05-03T13:30:0003 May 2021 13:30:00
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