ENS 52138
ENS Event | |
|---|---|
07:42 Aug 1, 2016 | |
| Title | Plant Shutdown Due to Pressure Boundary Leakage Greater than Allowable Limit |
| Event Description | On August 1, 2016 at 0342 EDT St. Lucie Unit 1 commenced a unit shutdown required by Technical Specifications due to Reactor Coolant System Pressure Boundary Leakage in excess of the allowable limit of zero leakage. The leak was initially identified on July 31, 2016 at 2115 EDT as not Pressure Boundary leakage. After further analysis, the leak was determined to be Reactor Coolant System Pressure Boundary leakage at 0123 on August 1, 2016. The leakage is estimated as less than one tenth of a gallon per minute and is not impacting the ability to shut down the unit. Additional impact of the leak is under evaluation.
This report is submitted in accordance with 10CFR50.72(b)(2)(i) as 'The initiation of any nuclear plant shutdown required by the plant's Technical Specifications.' The location of the leak is on the Instrumentation piping welded connection at Flow Element FE-3311 attached to [the] Emergency Core Cooling System Injection header to Reactor Coolant System Loop 1A2. The leak activity is 0.167 microCuries per ml. The NRC Resident Inspector has been notified.
The purpose of this notification is to retract a previous report made on EN 52138. NRC notification was initially made as a result of a plant shutdown required by technical specifications (TS) for Reactor Coolant System (RCS) pressure boundary leakage. Subsequent to the initial report, St. Lucie has determined that the RCS leakage was from a seal weld on a threaded connection that was not pressure boundary leakage. However, the leak was non-isolable and required RCS depressurization to allow immediate investigation to ensure there were no faults in a RCS component body or pipe wall. The leakage was estimated to be less than one tenth of a gallon per minute and did not impact the ability to shut down the unit. No TS limits were exceeded during this event. Therefore, the plant shutdown to investigate and correct leakage past the seal weld of a threaded connection does not meet the reporting requirements of 10 CFR 50.72 or 10 CFR 50.73. The NRC Resident Inspector has been notified. Notified the R2DO (Blamey). |
| Where | |
|---|---|
Saint Lucie  Florida (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
| Time - Person (Reporting Time:+-1.15 h-0.0479 days <br />-0.00685 weeks <br />-0.00158 months <br />) | |
| Opened: | Thomas Plower 06:33 Aug 1, 2016 |
| NRC Officer: | Jeff Herrera |
| Last Updated: | Sep 23, 2016 |
| 52138 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Hot Standby (0 %) |
WEEKMONTHYEARENS 556932022-01-07T00:37:0007 January 2022 00:37:00
[Table view]10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Shutdown Initiated in Accordance with Technical Specifications ENS 521382016-08-01T07:42:0001 August 2016 07:42:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Plant Shutdown Due to Pressure Boundary Leakage Greater than Allowable Limit ENS 509772015-04-12T01:00:00012 April 2015 01:00:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Safety Injection Tank Outlet Piping Leak ENS 503102014-07-25T15:29:00025 July 2014 15:29:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Technical Specification Required Shutdown Due to a Safety Injection Valve Defect ENS 444852008-09-14T06:41:00014 September 2008 06:41:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Dropped Control Element Resulting in Entry Into Technical Specification Required Shutdown Lco ENS 438712007-12-28T09:50:00028 December 2007 09:50:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown - Dropped Cea ENS 420522005-10-12T18:40:00012 October 2005 18:40:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Shutdown Based on Loss of Two Channels of Containment Isolation Radiation Monitor 2022-01-07T00:37:00 | |