05000374/LER-2017-002, Regarding High Pressure Core Spray System Declared Inoperable Due to Cooling Water Strainer Backwash Valve Stem-Disc Separation
| ML17089A657 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 03/30/2017 |
| From: | Vinyard H Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RA 17-032 LER 17-002-00 | |
| Download: ML17089A657 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 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)(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)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 3742017002R00 - NRC Website | |
text
Exelon Generation.,
RA17-032 March 30, 2017 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 LaSalle County Station, Unit 2 Renewed Facility Operating License No. NPF-18 NRG Docket No. 50-374 LaSalle County Station 2601 North 21"' Road Marseilles, IL 61341 815-415-2000 Telephone www.exeloncorp.com 10 CFR 50.73
Subject:
Licensee Event Report 2017-002-00, High Pressure Core Spray System Declared Inoperable due to Cooling Water Strainer Backwash Valve Stem-Disc Separation In accordance with 1 O CFR 50.73(a)(2)(v)(D), Exelon Generation Company, LLC (EGG) is submitting Licensee Event Report (LEA) Number 2017-002-00 for LaSalle County Station, Unit 2.
There are no regulatory commitments in this letter. Should you have any questions concerning this report, please contact Mr. Guy V. Ford, Jr., Regulatory Assurance Manager, at (815) 415-2800.
Harold T. Vinyard Plant Manager LaSalle County Station
Enclosure:
Licensee Event Report cc:
Regional Administrator - NRG Region Ill NRG Senior Resident Inspector - LaSalle County Station
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 (06*2016)
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 />.
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Reported lessons learned are incorporated into the licensing process and led back to industry.
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LICENSEE EVENT REPORT (LEA)
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- 3. PAGE LaSalle County Station, Unit 2 05000374 1 OF 3
- 4. TITLE High Pressure Core Spray System Declared Inoperable due to Cooling Water Strainer Backwash Valve Stem-Disc Separation
- 5. EVENT DATE
- 6. LEA NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED I
SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO.
MONTH DAY YEAR NA NA FACILITY NAME DOCKET NUMBER 01 30 2017 2017 - 002 00 03 31 2017 NA NA
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: {Check all that apply)
D 20.2201 (bl D 20.2203(a)(3Hil D 50.73(a)(2)(ii)(A)
D 50.73(a)(2)(viii)(A) 1 D 20.2201 (dl D 20.2203(aH3Hill D 50.73(a)(2)(ii)(B)
D 50.73(a)(2)(viii)(B)
D 20.2203(a)(1 l D 20.2203(a)(4)
D so.13(aH2Hiiil D 50.73(a)(2)(ix)(A)
D 20.2203(aH2Hil D 50.36(c)(1 )(i)(A)
D 50.73(a)(2)(iv)(A)
D 50.73(a)(2)(x)
- 10. POWER LEVEL D 20.2203(a)(2)(iil D 50.36(c)(1 )(ii)(A)
D 50.73(a)(2)(v)(A)
D 13.11(a)(4l D 20.2203(a)(2)(iiil D so.3s(c)(2)
D 50.73(a)(2)(v)(B)
D 73.71 (a)(S)
D 20.2203(a)(2)(iv)
D so.4s(a)(3)(iil D 50.73(a)(2)(v)(C)
D 13.77(a)(1) 98 D 20.2203(a)(2)(v)
D 50.73(a)(2)(i)(A)
[gl 50.73(a)(2)(v)(D)
D 13.11(a)(2)(il D 20.2203(a)(2)(vi)
D 50.73(a)(2)(i)(B)
D 50.73(a)(2)(vii)
D 13.77(a)(2)(iil D 50.73(a)(2)(i)(C)
D OTHER Specify in Abstract below or in There were minimal safety consequences associated with the event since other emergency safety systems remained operable, including emergency core cooling system (ECCS) systems for Division 1 and Division 2 and their associated emergency diesel generators. The DGCW system remained functional as the system retained the ability to provide the required flow through the system. However, this event was considered a safety system functional failure, as defined in accordance with NEI 99-02, Regulatory Assessment Performance Indicator Guideline.
CORRECTIVE ACTIONS
OD The station performed troubleshooting to identify the initial condition of the valve. The Division 3 DGCW strainer backwash valve 2E22-F319 was cut out and replaced by a new stainless steel type. The degraded valve was sent offsite for component failure diagnostics and analysis. An apparent cause investigation was performed which determined the cause of the valve's stem-disc separation was accelerated corrosion and pitting of the carbon-steel valve internals in a raw water system environment.
An extent of condition review identified two installations of the Anchor Darling valve model# 94-14040. Therefore, the specific extent of condition is the (Unit 1) 1 E22-F319 and (Unit 2) 2E22-F319 DGCW Strainer backwash valves. The subject Unit 2 Division 3 DGCW strainer backwash valve 2E22-F319 was replaced with a stainless-steel type on February 1, 2017. The Unit 1 1 E22-F319 valve is scheduled to be replaced on November 27, 2017.
The extent of condition applies to the Unit 1 and Unit 2 DGCW and core standby cooling system (CSCS) valves that are exposed to a raw water environment. Some of these valves have been replaced with stainless-steel components, while other valves are scheduled for replacement in future refueling outages.
PREVIOUS OCCURRENCES
A review of LaSalle Station Licensee Event Reports for the past three years, related to stem-disc separation issues or HPCS system issues, identified the following similar instance at LaSalle Station.
LER 373-2015-001:
On December 29, 2014, Unit 2 was in Mode 1 at 100 percent power with a operability test in progress on the 28 DG. During performance of the test, operators noticed a small leak of about one drop per second coming from the casing of the 28 HPCS DGCW pump. The 28 DG and supported HPCS system were declared inoperable. The station entered TS 3.5.1 Required Actions 8.1 to verify the RCIC system was operable and 8.2 to restore HPCS to operable status within 14 days. Examination of the pump casing determined the apparent cause of the leak was erosion from impeller flow impingement. The pump was replaced and returned to service on January 3, 2015. This event did not involve stem-disc separation in a valve; however, it was related to a failure affecting performance of the HPCS system.
COMPONENT FAILURE DATA
Manufacturer: Anchor Darling (A391)
Device: Gate Valve, 4-inch, Carbon-Steel Component ID: Model 94-14040 Page _3_ of _3_