ENS 54687
ENS Event | |
|---|---|
07:54 May 1, 2020 | |
| Title | En Revision Imported Date 5/18/2020 |
| Event Description | EN Revision Text: TECHNICAL SPECIFICATION REQUIRED SHUTDOWN DUE TO REACTOR COOLANT SYSTEM PRESSURE BOUNDARY LEAKAGE
At 1000 EDT on May 1 2020, Operations commenced a shutdown of DC Cook Unit 2 to comply with LCO 3.4.13, Condition B Reactor Coolant System (RCS) pressure boundary leakage. At 0354 EDT on May 1, 2020, Operations detected an estimated 8 gpm Reactor Coolant System leak. The source of the leak could not be identified and Tech Spec 3.4.13, Condition A was entered for unidentified RCS leakage in excess of the 0.8 gpm limit. At 0745 EDT on May 1, 2020, Unit 2 entered LCO 3.4.13, Condition B when the 4-hour limit to complete the required actions of Condition A could not be met. At 0945 EDT on May 1, 2020, Unit 2 entered LCO 3.4.13, Condition B when the 4-hour limit to complete the required actions of Condition A could not be met. At 0945 EDT on May 1, 2020, inspections inside containment identified the leak as pressure boundary leakage from a pressurizer spray line which also requires entry into LCO 3.4.13, Condition B. At 1059 EDT on May 1, Unit 2 was tripped from 15 percent power. All systems functioned normally. This event is reportable under 10 CFR 50.72(b)(2)(i), the initiation of any nuclear plant shutdown required by the plant's Technical Specifications as a 4-hour report and under 10 CFR 50.72 (b)(3)(ii)(A), degraded condition, as an 8-hour report. The NRC Resident Inspector has been notified.
The condition identified in EN #54687, pursuant to 10 CFR 50.72 (b)(3)(ii)(a) has been evaluated, and has been determined not to be RCS pressure boundary leakage. As such, the 8-hour report is being retracted, as it is not an event or condition that results in, 'the condition of the nuclear power plant, including its principal safety barriers, being seriously degraded.' The leakage was subsequently determined to be from the tell-tale nipple of a pressurizer spray valve, not from the pressurizer spray line piping as previously reported. The Reactor Coolant Pressure Boundary (RCPB) is formed by the valve body, plug, seat, body to bonnet extension, and bonnet of the pressurizer spray valve. Therefore, the leakage is not RCPB leakage. There is no change to the 4-hour report made under 10 CFR 50.72(b)(2)(i), the initiation of any nuclear plant shutdown required by the plant's Technical Specifications. The NRC Resident Inspector was notified of this retraction. Notified R3DO (Stone). |
| Where | |
|---|---|
Cook  Michigan (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| Time - Person (Reporting Time:+3.98 h0.166 days <br />0.0237 weeks <br />0.00545 months <br />) | |
| Opened: | Rodney Pickard 11:53 May 1, 2020 |
| NRC Officer: | Donald Norwood |
| Last Updated: | May 15, 2020 |
| 54687 - NRC Website | |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
WEEKMONTHYEARENS 546872020-05-01T07:54:0001 May 2020 07:54:00
[Table view]10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Reactor Coolant System Pressure Boundary Leakage ENS 511062015-05-31T20:00:00031 May 2015 20:00:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Failure of an Emergency Diesel Generator ENS 510042015-04-23T06:10:00023 April 2015 06:10:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Manual Reactor Trip Due to a Secondary Plant Transient ENS 481202012-07-19T19:30:00019 July 2012 19:30:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Tech Spec Required Shutdown Due to Inability to Restore Main Steam Isolation Automatic Actuation Logic and Actuation Relays within the Required Time ENS 427392006-07-30T11:30:00030 July 2006 11:30:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Shutdown for High Containment Air Temperature 2020-05-01T07:54:00 | |