05000373/LER-2017-001, Regarding Reactor Core Isolation Cooling System Inoperable Longer than Allowed by the Technical Specifications Due to Low Suction Pressure Trips
| ML17039A744 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 02/08/2017 |
| From: | Vinyard H Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RA17-014 LER 17-001-00 | |
| Download: ML17039A744 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 3732017001R00 - NRC Website | |
text
Exelon Generation© RA17-014 February 8, 2017 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 LaSalle County Station, Unit 1 Renewed Facility Operating License No. NPF-11 NRG Docket No. 50-373 LaSalle County Station 2601 North 21 51 Road Marseilles, IL 61341 815-415-2000 Telephone www.exeloncorp.com 10 CFR 50.73
Subject:
Licensee Event Report 2017-001-00, "Reactor Core Isolation Cooling System Inoperable Longer than Allowed by the Technical Specifications due to Low Suction Pressure Trips" Exelon Generation Company, LLC (EGG) is submitting Licensee Event Report (LER) Number 2017-001-00 for LaSalle County Station Unit 1 in accordance with 1 O CFR 50.73(a)(2)(i)(B).
There are no regulatory commitments contained 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.
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 />
- Reported lessons learned are incorporated into the licensing process and Jed back to industry.
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LICENSEE EVENT REPORT (LEA)
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- 3. PAGE LaSalle County Station, Unit 1 05000373 1 OF 3
- 4. TITLE Reactor Core Isolation Cooling System Inoperable Longer than Allowed by the Technical Specifications due to Low Suction Pressure Trips
- 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 12 16 2016 2017
- 001
. 00 02 08 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)(3)(il D 50.73(a)(2)(ii)(A)
D 50.73(a)(2)(viii)(A) 1 D 20.2201 (dl D 20.2203(a)(3)(ii)
D 50.73(a)(2)(ii)(B)
D 50.73(a)(2)(viii)(B)
D 20.2203(a)(1 l D 20.2203(a)(4l D so.13(a)(2)(mJ D 50.73(a)(2)(ix)(A)
D 20.2203(a)(2)(il 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)(nJ D 50.36(c)(1 )(ii)(A)
D 50.73(a)(2)(v)(A)
D 13.11 (a)(4l D 20.2203(a)(2)(mJ D so.3s(c)(2J D 50.73(a)(2)(v)(B)
D 13.11 (a)(sJ D 20.2203(a)(2)(iv)
D so.4e(aJ(3J(iil D 50.73(a)(2)(v)(C)
D 13.77(aJ(1J 100 D 20.2203(a)(2)(v)
D 50.73(a)(2)(i)(A)
D 50.73(a)(2)(v)(D)
D 13.77(a)(2)(il D 20.2203(a)(2)(vil 181 50.73(a)(2)(i)(B) 0 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
CAUSE OF EVENT
The component that caused both of the low suction pressure trips was the EG-R hydraulic actuator for the RCIC governor valve. The EG-R component failure analysis (report dated December 16, 2016) determined the failure mechanism was due to the presence of internal iron oxide deposits on the control lands and on the inside of the bore. These deposits resulted in binding between precision internal components which caused intermittent operation of the EG-R. Rust deposits and wear was also noted on several actuator components, which suggested there had been moisture entrained in the oil.
The root cause for both of the Unit 1 RCIC low suction pressure trips was inadequate management of the EG-R hydraulic actuator PM strategy. The site did not perform preventative maintenance on Unit 1 RCIC EG-R on an interval that would prevent internal fouling from adversely affecting RCIC governor performance.
REPORTABILITY AND SAFETY ANALYSIS
00 This event is reportable in accordance with 1 O CFR 50.73(a)(2)(i)(B) as a condition prohibited by TS due to the failure to complete TS 3.5.3, Required Action A.2 within the specified Completion Time of 14 days. The Unit 1 RCIC inoperable period was from the first system trip on October 18, 2016, to when full restoration of the system was completed on November 20, 2016. The EG-R was determined by failure analysis completed on December 16, 2016, to be the failure mechanism that caused Unit 1 RCIC inoperability to be longer than the allowed 14-day Completion Time. The events for the October 2016 and November 2016 RCIC trips did not meet the reporting threshola in accordance with 10 CFR 50.72.
There were no safety consequences associated with the events since there was no loss of safety function. RCIC system is not an Engineered Safety Feature (ESF) system, and no credit is taken in the safety analyses for the RCIC system operation. RCIC does not meet the threshold for failure of a single train non-safety system since it is not included in the safety analysis. In addition, the Unit 1 High Pressure Core Spray (HPCS) system remained available during the period that the Unit 1 RCIC system was inoperable. There were no actual demands for either Unit 1 RCIC or Unit 1 HPCS during this period.
CORRECTIVE ACTIONS
The degraded EG-R was replaced. The degraded EG-R was sent off-site for component failure analysis. Post-maintenance testing and a detailed review of historical performance data indicated improved EG-R governor positioning. The Unit 1 RCIC system was declared operable on November 20, 2016, at 19:05 CST. A root cause investigation identified additional corrective actions, including actions to improve RCIC system trending and to develop and implement an appropriate PM strategy that includes EG-R device-specific replacement frequency and EG-R oil reservoir clean-flush frequency. The EG-R on the Unit 2 RCIC system was also successfully replaced as part of the extent of condition review.
PREVIOUS OCCURRENCES
A review of Licensee Event Reports for the past three years identified no previous similar occurrences at LaSalle Station.
COMPONENT FAILURE DATA
Part Description: Actuator, Hydraulic, Governor Manufacturer: Woodward Model No.: A9903-026 Page _3_ of _3_