ENS 52456
ENS Event | |
|---|---|
04:00 Dec 22, 2016 | |
| Title | Emergency Diesel Generators Declared Inoperable |
| Event Description | With D.C. Cook Unit 1 in Mode 1 and 100 percent power and Unit 2 in Mode 4 during a refueling outage, the following emergency diesel generators (EDGs) were declared inoperable due to a discovered design and manufacturing issue involving some of the diesel fuel pumps/injectors in each of the following EDGs:
Unit 1 CD (Train A) EDG, Unit 2 AB (Train B) EDG, and Unit 2 CD (Train A) EDG Due to both Unit 2 EDGs being inoperable, Unit 2 is required to be in Mode 5 by 1300 [EST] on 12/23/16. Unit 1 is required to restore its emergency diesel generator within 14 days (by 2300 [EST] on 1/04/17). In connection with both trains of Unit 2 EDGs being inoperable, this is being reported as an 8-hour report pursuant to 10CFR50.72(b)(3)(v)(D) as loss of safety function in connection with mitigating the consequences of an accident. The NRC Resident Inspector has been informed. Unit 1 maintenance will be prioritized over Unit 2 and Unit 2 will most likely proceed to Mode 5.
The condition reported in ENS 52456 pursuant to 10 CFR 50.72(b)(3)(v)(D) has been evaluated, and determined not to be a loss of safety function in connection with mitigating the consequences of an accident, and is being retracted. With D.C. Cook Unit 1 in Mode 1 and 100% power and Unit 2 in Mode 4 during a refueling outage, the following Emergency Diesel Generators (EDGs) were declared inoperable due to a discovered design and manufacturing issue involving some of the diesel fuel pumps/injectors in each of the following EDGs: Unit 1 CD (Train A) EDG, Unit 2 AB (Train B) EDG, and Unit 2 CD (Train A) EDG. Subsequent endurance testing was performed on selected Delivery Valve Holders (DVH), which were the affected components of the diesel fuel pumps/injectors, to evaluate the expected degradation of the DVHs during the EDG mission. This testing determined that the identified design and manufacturing issue would not have prevented the EDGs from performing their intended safety functions. Therefore, all EDGs were OPERABLE and did not result in a loss of safety function in connection with mitigating the consequences of an accident. The NRC Resident Inspector was notified of this retraction. Notified the R3DO (Kunowski). |
| Where | |
|---|---|
Cook  Michigan (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| LER: | 05000316/LER-2016-002 |
| Time - Person (Reporting Time:+1.75 h0.0729 days <br />0.0104 weeks <br />0.0024 months <br />) | |
| Opened: | Bud Hinckley 05:45 Dec 22, 2016 |
| NRC Officer: | Steven Vitto |
| Last Updated: | May 22, 2017 |
| 52456 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Hot Shutdown (0 %) |
| After | Hot Shutdown (0 %) |
Cook with 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
WEEKMONTHYEARENS 524562016-12-22T04:00:00022 December 2016 04:00:00
[Table view]10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Emergency Diesel Generators Declared Inoperable ENS 501492014-05-25T13:42:00025 May 2014 13:42:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Control Room Ventilation Boundary Door Inoperable ENS 411112004-10-11T04:20:00011 October 2004 04:20:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Containment Ventilation Isolation System Inoperable During Fuel Movement 2016-12-22T04:00:00 | |