05000282/LER-2007-001, Re Unit 1 Train B ECCS Inoperable Longer than Allowed by Technical Specifications Due to Inoperable Breaker
| ML071550269 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 06/04/2007 |
| From: | Wadley M Nuclear Management Co |
| To: | Document Control Desk, Plant Licensing Branch III-2 |
| References | |
| L-PI-07-043 LER 07-001-00 | |
| Download: ML071550269 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 2822007001R00 - NRC Website | |
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Prairie Island Nuclear Generating Plant Operated by Nuclear Management Company, LLC June 4,2007 L-PI-07-043 10 CFR 50.73 U S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Unit 1 Docket 50-282 License No. DPR-42 LER 1-07-01, Unit 1 Train B Emergency Core Cooling System (ECCS) Inoperable Longer Than Allowed bv Technical Specifications Due to Inoperable Breaker Licensee Event Report (LER) 1-07-01 is enclosed. The LER describes Unit 1 operation with 12 Safety Injection pump being inoperable longer than allowed by TS 3.5.2 Condition A. This event is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by Technical Specifications.
Summary of Commitments This letter contains one new commitment and no revisions to existing commitments:
NMC will supplement this LER after the cause evaluation is completed.
Michael D. Wadley Site Vice President, Prairie Island Nuclear Generating Plant Nuclear Management Company, LLC Enclosure cc:
Administrator, Region Ill, USNRC Project Manager, Prairie Island, USNRC Resident Inspector, Prairie Island, USNRC Glenn Wilson, State of Minnesota 171 7 Wakonade Drive East Welch, Minnesota 55089-9642 Telephone: 651.388.1 121
ENCLOSURE LICENSEE EVENT REPORT 1-07-01 3 Pages Follow
, the NRC may not conduct or sponsor, FACILITY NAME OCKET NUMBER On April 3, 2007, Prairie Island Nuclear Generating Plant (PINGP) operators discovered the closing springs on the breaker for the 12 safety injection (SI) pump were discharged with the breaker open. NMC believes the charging motor failed the last time the breaker was closed to run the pump, which was March 15, 2007. Thus, the 12 SI pump was inoperable longer than the Completion Time of Technical Specification (TS) 3.5.2, Condition A, allows and this event is being reported in accordance with 10 CFR 50.73.(a)(2)(i)(B) as a condition prohibited by Technical Specifications.
The breaker was replaced with a spare and on April 4, 2007, TS 3.5.2, Condition A, was exited after successful testing of the breaker. The cause of the charging motor failure is under investigation and this LER will be supplemented after the cause evaluation is completed. U.S. NUCLEAR REGULATORY COMMISSION (1-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
EVENT DESCRIPTION
On April 3, 2007, Prairie Island Nuclear Generating Plant (PINGP) operators discovered the closing springs on the breaker' for the 12 safety injection (SI) pump2 were discharged with the breaker open.
NMC believes the charging motor3 failed the last time the breaker was closed to run the pump, which was March 15, 2007. The breaker was replaced with a spare and on April 4, 2007, the 12 SI pump was declared operable after successful testing of the breaker.
EVENT ANALYSIS
The breaker for the 12 SI pump was discovered to be inoperable on April 3, 2007. Indications are that the breaker had been inoperable since the last time the pump was run on March 15, 2007.
Technical Specification (TS) 3.5.2, Condition A, allows 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to restore operability of an inoperable emergency core cooling system4 (ECCS) train. If the Required Action and Completion Time of TS 3.5.2, Condition A, is not met, Condition B requires the affected unit be in Mode 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 4 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. In this case one train of ECCS (12 SI pump) was inoperable for longer than allowed by TS 3.5.2, Condition A, without taking Unit 1 to Mode 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> or Mode 4 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
Thus, this event is being reported in accordance with 10 CFR 50.73.(a)(2)(i)(B) as a condition prohibited by Technical Specifications.
Impact on Safety System Functional Failure Performance Indicator The redundant 11 SI pump was operable during the time the 12 SI pump was inoperable. Therefore, this event does not represent a loss of safety function. Consequently, this event is not reportable per I
OCFR 50.73(a)(2)(v).
SAFETY SIGNIFICANCE
This event did not result in a loss of the emergency core cooling system function, since the 11 SI pump remained operable. Thus, this event did not affect the health and safety of the public and the safety significance of this event is considered minimal.
1 Ells Component Code: BKR Ells Component Code: P 3 Ells Component Code: MO Ells System Code: BQ U.S. NUCLEAR REGULATORY COMMISSION (1-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
CAUSE
NMC is conducting a cause evaluation to determine why the closing springs were found discharged Preliminary indication is that the charging motor for the closing springs failed the last time the pump was run. The cause of the failed charging motor is still being evaluated. NMC will supplement this LER after the cause evaluation is completed.
CORRECTIVE ACTION
The 12 SI pump was restored to operability by replacing the breaker. As an interim measure, operators have been performing additional inspections on 4kV safeguards breakers to verify the closing springs are charged. The cause evaluation will determine the actions necessary to prevent recurrence. NMC will supplement this LER after the cause evaluation is completed.
PREVIOUS SIMILAR EVENTS
Review of Licensee Event Reports for Unit 1 and Unit 2 since 2004 found no previous similar events.