05000352/LER-2016-003, Regarding Plant Shutdown Required by Technical Specification Due to a Pressure Boundary Leak
| ML16139A428 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 05/18/2016 |
| From: | Libra R Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LG-16-060 LER 16-003-00 | |
| Download: ML16139A428 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3522016003R00 - NRC Website | |
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Exelon Generation LG-16-060 May 18, 2016 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Unit 1 Renewed Facility Operating License No. NPF-39 NRG Docket No. 50-352 10CFR50.73
Subject:
LER 2016-003-00, Plant Shutdown Required by Technical Specifications This Licensee Event Report (LER) addresses a plant shutdown required by Technical Specifications. This LER also reports an event that resulted in the condition of the plant, including its reactor coolant system pressure boundary, being degraded. This LER is being submitted pursuant to the requirements of 10CFR50.73(a)(2)(i)(A) and 10CFR50.73(a)(2)(ii)(A).
There are no commitments contained in this letter.
If you have any questions, please contact Robert 8. Dickinson at (610) 718-3400.
Respectfully,
~~
Richard W. Libra Vice President - Limerick Generating Station Exelon Generation Company, LLC cc: Administrator Region I, USNRC USNRC Senior Resident Inspector, LGS
NRC FORM 366 (01-2014)
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (01-2014)
LICENSEE EVENT REPORT (LER)
(See Page 2 for required number of digits/characters for each block)
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.
Reported lessons learned are incorporated into the licensing process and fed back to industry.
Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME Limerick Generating Station, Unit 1
- 2. DOCKET NUMBER 05000352
- 3. PAGE 1 OF 3
- 4. TITLE Plant Shutdown Required by Technical Specification Due to a Pressure Boundary Leak
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL NUMBER REV NO.
MONTH DAY YEAR FACILITY NAME DOCKET NUMBER 05000 03 20 2016 2016 -
003
- - 00 05 18 2016 FACILITY NAME DOCKET NUMBER 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 1 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 14.5 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(A) 73.71(a)(4) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(C)
OTHER 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D)
Specify in Abstract below or in LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET The SDC return is a 12-inch diameter line equipped with an outboard motor operated valve (MOV) primary containment isolation valve (PCIV) and an inboard testable check valve PCIV.
The testable check valve has a bypass line that is equipped with an air operated valve (AOV)
PCIV which is used to equalize the differential pressure across the testable check valve disc when the valve is opened during stroke testing. Testable check valves are also used in similar applications on low pressure coolant injection (LPCI) and core spray (CS) injection lines. The SDC valve is subject to vibration induced high cycle fatigue due to recirculation pump flow induced vibration. The LPCI and CS injection lines socket welds are not subject to vibration induced high cycle fatigue.
The affected section of bypass line piping was replaced with a new socket weld with a 2x1 weld to improve pipe stability and minimize stresses at the toe as a result of the 2x1 weld configuration. A 2x1 weld was also applied at the similar valve body socket welds for the HV-051-1F050A residual heat removal (RHR) side and HV-051-1F050B RHR and reactor side welds.
Cause of the Event
The Unit 1 A RHR Shutdown Cooling Return Check Valve equalizing line developed a crack at the toe of the weld due to high cyclic fatigue induced by vibration from the reactor recirculation system (Apparent Cause).
Corrective Action Completed The Unit 1 welds were reworked to EPRI 2x1 at select locations on the A and B RHR Shutdown Cooling Return check valve equalizing lines for HV-051-1F050A and 50B.
Corrective Action Planned The similar Unit 2 welds on equalizing lines for HV-051-2F050A and 50B will be examined and reinforced. The scope will be added into the next refueling outage (2R14) currently scheduled for April 2017.
Previous Similar Occurrences There were no previous similar occurrences of pressure boundary leakage in the past 5 years.
Component data:
System BO RHR/Low Pressure Coolant Injection System Component ISV Valve, Isolation Component number HV-051-1F050A Manufacturer A585 Weir Valves & Controls USA Inc.
Model number 50301-A Serial Number 2-50301-A