ML20072F075
| ML20072F075 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 08/15/1994 |
| From: | Ohanlon J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 94-427, NUDOCS 9408230198 | |
| Download: ML20072F075 (5) | |
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VHf 01NIA HW C'TidC AND POWmf COMPANY lt ie n m m n, Vi noin A erieel August 15, 1994 U. S. Nuclear Regulatory Commission Serial No.94-427 Attention: Document Control Desk NAPS /JHUMAE R8 Washington, D. C. 20555 Docket Nos.
50-338
'50-339 License Nos.
NPF-4 NPF-7 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 and 2 HiSPECTION REPORT NOS. 50-338/94-13 AND 50-339/94-13 REPLY TO A NOTICE OF VIOLATION We have reviewed your letter _ of July 13, 1994, which referred to the inspection conducted at North Anna Power Station from May 22,1994 to June 18,1994, and the associated Notice of Violation which was reported in inspection Report Nos. 50-338/94-13 and 50 339/94-13.
Our reply to the Notice of Violation is attached.
Although we agree that a violation of 10 CFR 50 Appendix B, Criterion V occurred, it is our position that the supporting licensee requirements cited in the violation are incorrect. Alternate requirements have been identified.
Your letter that transmitted the Notice of Violation expressed concern that work was performed on equipment which provided one offsite power source for safety related plant loads without procedural controls and that an opportunity to identify that there was a problem was missed because the equipment was not returned to service properly. Future maintenance practices will ensure appropriate maintenance testing-on the reserve station service transformers prior to returning a transformer to service.
in addition, a detailed root cause evaluation (RCE) is being performed.
if you have any further questions, please contact us.
Very truly yours,
' mo i
~
James P. O'Hanlon Senior Vice President - Nuclear Attachment F
b0COj 9408230199 940815 PDR ADOCK 03000338 0
PDR i
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cc:
U. S. Nuclear Regulatory Commission Region ll 101 Marietta Street, N.W.
Suite 2900 Atlanta, Georgia 30323 Mr. R. D. McWhorter NRC Senior Resident inspector North Anna Power Station
REPLY TO A NOTICE OF VIOLATION INSPECTION REPORT NOS. 50-338/94-13 AND 50-339/94-13 NRC COMMENT During an NRC inspection conducted from May 22,1994 through June 18,1994,a violation of NRC requirements was identified.
In accordance with the " General Statement of Policy and Procedure for NRC Enforcement Actions," 10 CFR Part 2, Appendix C, the violation is listed below:
10 CFR 50, Appendix B, Criterion V, and the licensee's Quality Assurance Program (Updated Final Safety Analysis Report, Chapter 17, Quality Assurance, Section 17.2.5, instructions, Procedures and Drawings) collectively require that activities affecting quality shall be prescribed by documented procedures of a type appropriate to the circumstances and shall be accomplished in accordance with these procedures.
Virginia Power Nuclear Switchyard Procedure Policy Document states that procedures will be written and used for construction and maintenance activities being performed in the switchyard which could pose a risk of causing a loss of off-site power to plant loads.
Contrary to the above, the licensee failed to develop a procedure for performing maintenance on the switchyard B Reserve Station Service transformer which is one source of off site power for plant loads. As a result, the transformer was placed in service from approximately 4:00 a.m. on June 4 until 2:00 p.m. on June 8 without an operable automatic load tap changer.
This is a Severity Level IV Violation (Supplement 1).
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t REPLY TO A NOTICE OF VIOLATION Before responding to the specific violation, we have one comment. We agree that a violation occurred, but that the violation was not contrary to the Virginia Power Nuclear Switchyard Policy as stated in the NRC Notice of Violation.
Rather, the violation was in failing to have adequate procedures to control return-to-service testing following maintenance activities on the B Reserve Station Service Transformer (RSST).
The Virginia Power Nuclear Switchyard Policy had been developed to address maintenance on switchyard components-which could potentially interfere with other active station electrical components, and have an adverse impact on safe station operations while the switchyard maintenance was in progress. In this case, the policy was not applicable because the B RSST had been properly isolated from the operable electrical system and cou!d not have had adversely affected safe operation of the station during the maintenance evolution.
1.
REASON FOR THE VIOLATION Prior to event, detailed plans had been established to replace the B RSST, at power, due to an increasing oil level in the tap changer section of the transformer. Temporary Maintenance Operating Procedure,1-TMOP-26.78, B RSS Transformer Changeout, was developed to control the removal of the transformer from service, isolate the transformer from the station electrical system and return the transformer to service. However, plant conditions led to deferring the transformer replacement until shutdown conditions could be established. On June 1,~ 1994, Unit 2 was shutdown for a forced outage and planning commenced for the transformer replacement.
Just prior to the transformer replacement, it was determined that all the necessary parts were not available. At that time, it was decided to perform maintenance on the B RSST instead of replacing it.
l Temporary procedure 1-TMOP-26.78 was used by station personnel for the removal from and return to service of reserve station service transformers.
1 Maintenance was completed by substation personnel and the B RSST was returned to service.
After placing several large ! cads in service, the control i
room operators observed low voltages on buses supplied by the B RSST.
The maintenance performed was considered " skill of the craft" and no specific procedures were utilized by the substation personnel. This is an acceptable practice because return-to-service procedures are normally utilized as the administrative barrier to ensure that electrical components are fully operable prior to returning them to serv!ce. In this case, the return to service testing following maintenance which utilized temporary maintenance operating procedure,1-TMOP-26.78, was inadequate and the mispositioned automatic load tap changer voltage sensing circuit switch was not detected prior to returning the B RSST to service.
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2.
CORRECTIVE STEPS WHICH HAVE BEEN TAKEN AND THE RESULTS ACHIEVED After discovering that the B RSST automatic load tap changer voltage sensing circuit switch was open, the Action Statement of Technical Specification 3.8.1.1 was entered. Following reclosure of the automatic load tap changer voltage sensing circuit switch and functional testing, the B RSST was returned to operable status and the Technical Specification Action Statement was cleared.
A detailed engineering analysis was performed to determine if the mispositioned-automatic load tap-changer voltage sensing circuit switch rendered the Technical Specification required offsite power source inoperable.
Plant conditions that existed during the time frame that the automatic load tap changer voltage sensing circuit switch was mispositioned were used to analyze the plant response to design basis accident conditions. The analysis results indicated that premature separation of the emergency bus from the offsite power source would not have occurred during a design basis accident. Therefore, it was concluded that the mispositioned automatic load tap changer voltage sensing circuit switch did not render a Technical Specification required offsite power source inoperable.
Maintenance operating procedures,1-MOP-26.77,1-MOP-26.78 and 1-MOP-26.79, A, B and C RSS Transformer, have been revised to verify the proper position of the automatic load tap changer voltage sensing circuit switch prior to returning the transformer to service. These procedures now include a functional test of the load tap changer to ensure it functions properly prior to returning the transformer to service.
3.
CORRECTIVE STEPS WHICH WILL BE TAKEN TO AVOID FURTHER VIOLATIONS A detailed Root Cause Evaluation (RCE) of the event is being performed.
Management will review and approve the RCE and its recommendations, as appropriate. Corrective actions and schedules will be established by August 31,1994. Management willinform the NRC Resident inspectors of the results of the root cause evaluation and the corresponding corrective action plan.
4.
THE DATE WHEN FULL COMPLIANCE WILL BE ACHIEVED Full compliance was achieved when the revisions to the maintenance operating procedures described in Section 2 were implemented.
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