05000298/LER-2016-001, Regarding De-Energized High Pressure Coolant Injection Auxiliary Lube Oil Pump Caused by Relay Failure Results in Loss of Safety Function and a Condition Prohibited by Technical Specifications
| ML16181A054 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 06/21/2016 |
| From: | Limpias O Nebraska Public Power District (NPPD) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NLS2016036 LER 16-001-00 | |
| Download: ML16181A054 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v), Loss of Safety Function 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) |
| 2982016001R00 - NRC Website | |
text
H Nebraska Public Power District Always there when you need us NLS2016036 June 21, 2016 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001
Subject:
Licensee Event Report No. 2016-001-00 Cooper Nuclear Station, Docket No. 50-298, DPR-46
Dear Sir or Madam:
The purpose of this correspondence is to forward Licensee Event Report 2016-001-00.
There are no new commitments contained in this letter.
'"""""".......... Limpias Vice President Nuclear-Chief Nuclear Officer
/jo Attachment: Licensee Event Report 2016-001-00 cc:
Regional Administrator w/attachment USNRC - Region IV Cooper Project Manager w/attachment USNRC - NRR Project Directorate IV-1 Senior Resident Inspector w/attachment USNRC-CNS SRAB Administrator w/attachment NPG Distribution w/attachment INPO Records Center w/attachment via ICES entry SORC Chairman w/attachment CNS Records w/attachment COOPER NUCLEAR STATION P.O. Box 98 /Brownville, NE 68321-0098 Telephone: (402) 825-3811 /Fax:* (402) 825-5211 www.nppd.com
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BYOMB: NO. 3150-0104 EXPIRES: 10/31/2018 (11-2015)...,,.-.
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 fed back to industry.
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Send comments regarding burden estimate to the FOIA, Privacy and Information Collections LICENSEE EVENT REPORT (LER)
Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and (See Page 2 for required number of Regulatory Affairs, N.EOB-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 digits/characters for each block) control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Cooper Nuclear Station 05000298 1of4
- 4. TITLE De-Energized High Pressure Coolant Injection Auxiliary Lube Oil Pump Caused by Relay Failure Results in Loss of Safety Function and a Condition Prohibited by Technical Specifications
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED YEAR ISEQUENTIALI REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR NO.
MONTH DAY YEAR 05000 NUMBER FACILITY NAME DOCKET NUMBER 04 25 2016 2016 -
001 -
00 06 21 2016 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 0 20.2201(b) 0 20.2203(a)(3)(i) 0 50.73(a)(2)(ii)(A) 0 50. 73(a)(2)(viii)(A) 1 0 20.2201(d)
D 20.2203(a)(3)(ii) 0 50.73(a)(2)(ii)(B) 0 50.73(a)(2)(viii)(B) 0 20.2203(a)(1)
D 20.2203(a)(4) 0 50.73(a)(2)(ii) 0 50.73(a)(:2)(ix)(A) 0 20.2203(a)(2)(i) 0 50.36(c)(1 )(i)(A) 0 50. 73(a)(2)(iv)(A) 0 5QJ3(a)(2)(x) 0 20.2203(a)(2)(ii) 0 50.36(c)(1 )(ii)(A) 0 50.73(a)(2)(v)(A) 0 l~f71(a)(4)
- 10. POWER LEVEL 0 20.2203(a)(2)(iii)
D 50.36(c)(2) 0 50. 73(a)(2)(v)(B) 0 73:?1 (a)(5)
' 1 0 20.2203(a)(2)(iv) 0 50.46(a)(3)(ii) 0 50. 73(a)(2)(v)(C) 0 73.77(a)(1)
~
100 0 20.2203(a)(2)(v) 0 50. 73(a)(2)(i)(A)
~ 50.73(a)(2)(v)(D) 0 73. 77(a)(2)(i) 0 20.2203(a)(2)(vi)
~ 50.73(a)(2)(i)(B) 0 50.73(a)(2)(vii) 0 73. 77(a)(2)(ii) 0 50.73(a)(2)(i)(C) 0 OTHER Specify in Abstract below or in Operations then declared HPCI inoperable at 2117 Central Daylight Time (CDT), resulting in entry into Technical Specifications Limiting Condition of Operation 3.5.1, Condition C, HPCI System Inoperable.
Investigation revealed that the electrical relay (27) [Allen Bradley 700DC Jype P relay] for the ALOP had been replaced on April 19, 2016, during the recent three-year required preventive maintenance window.
After various checks were made, it was discovered that the coil within the relay had failed after 133 hours0.00154 days <br />0.0369 hours <br />2.199074e-4 weeks <br />5.06065e-5 months <br /> of service. The relay is expected to provide three years of reliable service between replacements.
As such, it was concluded that the coil had sustained an infant mortality type failure.
The dedication process used by the vendor of the relay, Nu Therm, at the time the relay was purchased by CNS, consisted of verifying the pickup and dropout voltages, and verifying contact resistances. After purchase of the relay, but prior to installation, Nu Therm revised their dedication process to require additionally cycling the relay 30 times in addition to the previous voltage and resistance checks:.
The relay that failed was replaced with a new relay that was purchased in September 2013 from a
- !i different lot than the failed relay purchased in March 2011. After satisfactory completion of post work Ji testing of the ALOP, HPCI was declared operable at 1314 CDT on April 26, 2016.
BASIS FOR REPORT The HPCI System is a single train safety system. This condition is reportable in accordance with 10 CFR
- 50. 73(a)(2)(v) as "any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to... (D) Mitigate the consequences of an accident." The condition is also reportable in accordance with 10 CFR 50. 73(a)(2)(i)(B) as a condition prohibited by TS since, due to HPCI inoperability, the verification of the Reactor Core Isolation Cooling system operability exceeded the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> required completion time plus the 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> completion time to be in Mode 3 if this verification is not completed. The event was reported as Event Notification 51882.
SAFETY SIGNIFICANCE
This is a Safety System Functional Failure. There were no actual safety consequences associated with this event. The potential safety consequences of this event were minimal due to the limited duration the condition existed and the redundant/diverse core cooling systems which remained operable throughout the event. The HPCI system is an emergency core cooling system designed to inject water into the reactor vessel to provide core cooling. The total duration of inoperability, including the time prior to discovery of the condition was less than the 14 day Technical Specification Completion Time. During the time period of inoperability, other core cooling systems (Automatic Depressurization System, Core Spray, and Low Pressure Coolant Injection) were operable and would have adequately responded to a design basis event. The Reactor Core Isolation Cooling system was also operable during this event.
NRC FORM 366 (11-2015)
CAUSE
The root cause of the event was determined to be that the prior pre-installation checks performed by Nu Therm on the relay were inadequate to prevent the infant mortality failure that occurred in this case.
CORRECTIVE ACTIONS
Nulherm revised their dedication process such that this type of failure will be detected. In addition, there are no relays from this lot in storage at CNS; however a check of maintenance records found that some of the relays from this lot are installed in the plant. These installed relays are well beyond the infant mortality period and have performed as expected.
PREVIOUS EVENTS There have been no events reported in the last three years related to the HPCI ALoe, NRC FORM 366 (11-2015)