05000255/LER-2007-001, Failure to Perform Offsite Power Source Check
| ML070600639 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 03/01/2007 |
| From: | Harden P Nuclear Management Co |
| To: | Document Control Desk, NRC/NRR/ADRO |
| References | |
| LER 07-001-00 | |
| Download: ML070600639 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2552007001R00 - NRC Website | |
text
N Committed to Nucl Palisades Nuclear Plant Operated by Nuclear Management Company, LLC March 1,2007 10 CFR 50.73(a)(2)(i)(B)
U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Palisades Nuclear Plant Docket 50-255 License No. DPR-20 Licensee Event Report 07-001, Failure to Perform Offsite Power Source Check Licensee Event Report (LER)07-001 is enclosed. The LER describes the failure to perform an offsite power source check in accordance with Technical Specification requirements when one offsite electrical source was inoperable. This occurrence is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by the Technical Specifications.
Summary of Commitments This letter contains no new commitments and no revisions to existing commitments.
Paul A. Harden Site Vice President, Palisades Nuclear Plant Nuclear Management Company, LLC Enclosure (1 )
CC Administrator, Region Ill, USNRC Project Manager, Palisades, USNRC Resident Inspector, Palisades, USNRC 27780 Blue Star Memorial Highway
- Covert, Michigan 49043-9530 Telephone: 269.764.2000
ENCLOSURE 'I LER 07-001, Failure to Perform Offsite Power Source Check 3 Pages Follow
Estimated burden per response to comply with this mandatory collection request: 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />.
Reported lessons learned are incorporated into the licensing process and fed back to industry.
LICENSEE EVENT REPORT (LER)
Send comments regarding burden estimate to the Records and FOIAIPrivacy Service Branch (T-5 F52), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-(See reverse for required number of digitslcharacters for each block) oncluded for the period between May 16, 2006, and May 22, 2006. The results of the evaluation of ast operability for startup transformer 1-2 during this period were that startup transformer 1-2 should ave been declared inoperable on three separate occasions based on the recorded output voltage of e transformer. The inoperable periods occurred on May 18, May 19 and May 22; with the duration each inoperable period not exceeding 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />.
ircuit inoperable'was applicable. However, since the startup transformer's past periods of ffsite source check for the operable offsite circuit was not performed in accordance with the specified ompletion time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter.
heck within the specified completion time is reportable in U.S. NUCLEAR REGULATORY COMMISSION (1 -2001 )
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
Palisades Nuclear Plant DOCKET NUMBER 2 r 9 F l 05000-255 TEXT (If more space IS reqwred, use add~honal cop~es of NRC Form 366A) (17)
EVENT DESCRIPTION
On May 22, 2006, the automatic load tap changer for startup transformer 1-2 [XFMR;EB] was noted to be non-functional. Upon discovery, the startup transformer was declared inoperable until repairs were completed. Subsequently, it was recognized that past operability of startup transformer 1-2 needed to be conducted for the period of time that the startup transformer's automatic load tap changer was not functioning; which was determined to be the period between May 16, 2006, and May 22,2006.
On January 4, 2007, the evaluation of the past operability status of startup transformer 1-2 was concluded. The results of the evaluation were that startup transformer 1-2 should have been declared inoperable on three separate occasions, based on the recorded output voltage of the transformer. The inoperable periods occurred on May 18, May 19 and May 22; with the duration of each inoperable period not exceeding 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />.
Startup transformer 1-2 is associated with one of the two credited offsite power sources required by Technical Specification (TS) Limiting Condition For Operation (LCO) 3.8.1, "AC Sources -
Operating." Consequently, during the three identified periods of inoperability, TS LC0 3.8.1.A for one offsite circuit inoperable was applicable. However, since the startup transformer's past periods of inoperability were not recognized at the time, the required action of TS LC0 3.8.1.A.1 to perform an offsite source check for the operable offsite circuit was not performed in accordance with the specified completion time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter.
The failure to perform the offsite source check within the specified completion time is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by Technical Specifications.
CAUSE OF THE EVENT
The failire of the automatic load tap changer was attributed to mechanical binding internal to interlocked contactors.
CORRECTIVE ACTIONS
An extent of condition review was performed. No other similar components were identified.
The raisellower contactor set for the automatic load tap changer was replaced and tested satisfactorily.
NRC FORM 366.4 U.S. NUCLEAR REGULATORY COMMISSION (1 -2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
Palisades Nuclear Plant DOCKET NUMBER 2 I _ l m 05000-255 TEXT (If more space is requfred, use addfbonal copfes of NRC Form 366A) (17)
SAFETY SIGNIFICANCE
The safety significance of this occurrence is considered to be minimal. The intent of the offsite source check is to ensure a highly reliable power source remains with one offsite circuit inoperable by verifying the operability of the remaining required offsite circuit on a more frequent basis.
Although not verified in accordance with the TS requirements, the remaining offsite source and both emergency diesel generators were operable during each of the three periods of inoperability of startup transformer 1-2.
PREVIOUS SIMILAR EVENTS
None