ENS 48120
ENS Event | |
|---|---|
19:30 Jul 19, 2012 | |
| Title | Tech Spec Required Shutdown Due to Inability to Restore Main Steam Isolation Automatic Actuation Logic and Actuation Relays within the Required Time |
| Event Description | At 1530 on July 19, 2012, operators commenced shutdown of DC Cook Unit 1 to comply with LCO 3.3.2, Condition I when the 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> time limit to complete Condition C Required Action could not be completed.
At 0734 on July 19, 2012, operators identified that power had been lost to two of four Steam Generator Stop Valve Dump Valves (Dump Valves) on one of the two trains. DC Cook entered LCO 3.3.2 Condition B for Function 4a, manual initiation: 'restore required channel or train to operable within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.' DC Cook also entered LCO 3.3.2 Condition C for Function 4b, automatic actuation logic and actuation relays: 'restore required channel or train to operable within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.' Power was restored to one Dump Valve which was then declared operable at 1030. Efforts continue to restore power to the remaining Dump Valve. Enforcement Discretion was verbally granted by the Nuclear Regulatory Commission at 1736 on July 19, 2012 to begin at 1934 and end at 1934 on July 20, 2012. Upon receiving the Enforcement Discretion, the power reduction was stopped at 1738 at 50% power. This event is reportable under 10CFR50.72(b)(2)(i), 'The initiation of any nuclear plant shutdown required by the plant's Technical Specifications,' as a four (4) hour report. The DC Cook Sr. Resident NRC Inspector has been notified. |
| Where | |
|---|---|
Cook  Michigan (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
| Time - Person (Reporting Time:+-1.03 h-0.0429 days <br />-0.00613 weeks <br />-0.00141 months <br />) | |
| Opened: | Kurt Beran 18:28 Jul 19, 2012 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Jul 19, 2012 |
| 48120 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (50 %) |
WEEKMONTHYEARENS 571942024-06-27T05:59:00027 June 2024 05:59:00
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