ML20063D837
| ML20063D837 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 02/01/1994 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF ENFORCEMENT (OE), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 94-027, 94-27, EA-93-262, NUDOCS 9402080329 | |
| Download: ML20063D837 (6) | |
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VIltGINIA ELecTurc Ann Pownn~ COMI*ANY Ricunown,Vinoinx4 20e61
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February 1, 1994 H
Director, Office of Enforcement Serial No.94-027 U.S. Nuclear Regulatory Commission NAPS /JHlJMAE R6 Attention:' Document Control Desk Docket No.
50-339 Washington, D.C. 20555 License No.
NPF-7 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNIT 2 REPLYnTO A NOTICE OF VIOLATION AND PROPOSED IMPOSITION OF CIVIL PENALTY (EA 93-262)
We have reviewed your letter of January 7,1994, which. forwarded a Notice of Violation and a proposed imposition of a $15,000 civil penalty. Our Reply to the Notice of Violation and a check in payment of the civil penalty are provided as attachments to 1
this letter.
Recurring violations are of particular concern to us. We expect to learn from past experience and take the necessary corrective actions to prevent recurrence. The original concern was identified by us as an operating experience issue and has been aggressively pursued. Corrective actions from these events included,1) use of increasingly precise valve positioning techniques,2) use of increasingly accurate flow measurement instrumentation, 3) increasing the understanding of flow rate measurement applications and uncertainties, 4) prompt action to re-establish acceptable flow rates,5) revising the Technical Specification flow balance band and
'6) continued performance of high head safety injection flow balance testing, although not required by Technical Specifications, in order to verify design basis. flow requirements are established. ' We are fully committed to providing aggressive management oversight to fully understand and resolve this issue.
. lf you have any further questions, please contact us.
Very truly yours, bis
%1)b ;M W. L, Stewart 4
Senior Vice President - Nuclear Attachments 1.
Reply to the Notice of Violation p) 2.
Check for Payment of the Civil Penalty p,
9402080329 94o201 I
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jI PDR :ADOCK 0500o339 y
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cc:
Regional Administrator U.S. Nuclear Regulatory Commission Region 11 101 Marietta Street, N.W.
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Suite 2900 Atlanta, Georgia 30323 Mr. R. D. McWhorter NRC Senior Resident inspector North Anna Power Station 1
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J REPLY TO A NOTICE OF VIOLATION AND PROPOSED IMPOSITION OF CIVIL PENALTY (EA 93-262)
INSPECTION REPORT NOS. 50-338/93-28 AND 50-339/93-28 NRC COMMENT During an NRC inspection conducted on October 14 - October 20,1993, 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 -
Nuclear Regulatory Commission proposes to impose.a civil penalty pursuant to Section 234 of the Atomic Energy Act of 1954, as amended (Act),42 U.S.C. 2282 and 10 CFR 2.205. The particular violation and associated civil penalty are set forth below:
Technical Specification (TS) '4.5.2.h requires that under certain circumstances prior to entering Mode 3 each Emergency Core Cooling System (ECCS) subsystem be demonstrated operable by performing a flow balance test to verify for high head safety injection lines with a single pump running that, a) the sum of the injection line flow rates, excluding the highest flow rate, be greater than or equal to 359 gpm, b) the total pump flow rate be less than or equal to 660 gpm (650 gprn prior to issuance of Amendment 151 on August 4,1993) and, c) for cold leg injection balancing, a value of greater than or equal to 48.3 gpm will be used for simulated sealinjection flow during balancing.
Contrary to the above:
(1) For the period from October 25,1993, when Unit 2 entered Mode 3, to November 8, 1993, the ECCS subsystems were not demonstrated operable in accordance with TS 4.5.2.h. Specifically, on October 14, 1993, the sum of the injection line flow rates, excluding the highest flow rate were adjusted such that the sum was '
384 gpm.
On November 8,1993, the measurement and l data analysis methods used for reaching this conclusion that the flow rate had been adequately-restored were demonstrated to be faulty.
Specifically, the-instrumentation used on October _14,1993 to demonstrate compliance with TS 4.5.2.h was determined to have an error band greater than assumed in the October 14,1993 analysis of the measurements such that the adjusted flow rate was.not demonstrated to be greater than or equal to 359 gpm.
(2) For operating cycle 9 from April 21,1992 to September 7,1993, when Unit 2 was in Mode 3 or higher for part of that time, the ECCS subsystems were not demonstrated operable in accordance with TS 4.5.2.h.
On November 8,1993, the test instrumentation used on April 10 and 11,1992 to demonstrate compliance with TS 4.5.2.h was determined to have an error band greater than was assumed in the analysis of the April 1992 measuremente.
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Specifically, considering the test instrumentation indicated flow rates measured on April 10 and 11,1992, and the greater error band, the A and B centrifugal charging pumps were not demonstrated to be operable.
Level IV violation (Supplement 1) enal y-$
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REPLY TO A NOTICE OF VIOLATION 1.
ADMISSION OR DENIAL OF THE ALLEGED VIOLATION The violation is correct as stated.
2.
REASONS FOR THE VIOLATION A detailed root cause evaluation of the event is currently in progress. The preliminary cause of this event is flow measurement inaccuracies associateG with the " strap on" ultrasonic test instrumentation used during the Unit 2 high head safety injection flow balance test.
Previously accounted for uncertainties with ultrasonic test instrumentation for balancing the Unit 2 high head safety injection flow were larger than previously believed due to unfavorable system piping geometries.
This instrument inaccuracy caused the high head safety injection system to be outside Technical Specification surveillance requirements.
Although there was failure to meet Technical Specification 4.5.2.h requirements, the applicable safety analysis limits were met.
3.
CORRECTIVE STEPS WHICH HAVE BEEN TAKEN AND THE RESULTS ACHIEVED.
The cold leg safety injection throttle valves were adjusted so that the sum of the two lowest flow rates was equal to 384 gpm and the total pump flow was less than or equal to 660 gpm using " strap-on" ultrasonic instrumentation.
Loctile 290 Threadlocker@ was installed on each of the cold leg safety injection throttle valves stem to yoke bushing to prevent valve stem movement since flow is sensitive to minor adjustments.
The cold leg safety injection throttle valves were radiographed to confirm that i
they were in an "as built" condition with respect to the disc, disc nut and stem t
arrangement. The valve's vendor verified that the valves were intact.
Previously unaccounted for uncertainties in the Unit 2 high *.ad safety injection flow balance measurements due to unfavorable system piping geometries were identified. Subsequently, reactor coolant pump seal injection flow rates were adjusted to allow the high head safety injection flow balance to meet the requirements of Technical Specification 4.5.2.h.
Enforcement ' Discretion was requested and approved from meeting the 3
requirements of Technical Specifications 4.5.2.h.1.b and 4.5.2.h.1.c to re-establish acceptable high head safety injection flow rates. An Emergs.1cy Technical Specification change was requeste? -- approved to eliminate TS 4.5.2.h.1.c which specified the simulated react: wolant pump seal injection flow requirement for cold leg flow injection bal&ncing.
Licensee Event Report 50-339/93-007-00 was submitted on November 12, 1993 documenting the. failure to meet Technical Specification 4.5.2.h requirements.
This event was reviewed for applicability to North Anna Unit 1.
The review determined that Unit 1 continued to comply with Technical Specification 4.5.2.h requirements.
Other plant systems that use the ultrasonic test instrumentation to meet surveillance requirements were reviewed. It was determined that surveillance requirements for the affected plant systems continue to be met.
A review of the effectiveness of the Root Cause Evaluation program was performed, and it identified areas that require strengthening in order to prevent recurring problems. Corrective actions will be implemented as appropriate.
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CORRECTIVE STEPS WHICH WILL BE TAKEN TO AVOID FURTHER VIOLATIONS A detailed root cause evaluation, in accordance with the Virginia Power Root Cause Evaluation Program Manual, is currently being performed to determine the cause of the event. Potential causes being evaluated include throttle valve L
cavitation, check valves sticking / flow blockage, safety injection flow diversion during testing, throttle valve movement and branch line flow measurement errors. Management will review the recommendations from the root cause evaluaticn and determine appropriate actions to prevent recurrence of this event. An industry operating experience entry will be issued following the completion of the root cause evaluation.
Further evaluation of the Technical Specifications will be conducted to determine whether additional enhancements may be warranted. If additional enhancements are warranted, a Technical Specification change will be submitted.
5.
THE DATE WHEN FULL COMPLIANCE WILL BE ACHIEVED Full concliance with Technical Specification 4.5.2.h has been achieved.
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