ML20097E781
| ML20097E781 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 06/09/1992 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 92-367, NUDOCS 9206150029 | |
| Download: ML20097E781 (3) | |
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Vinoisir Ei.nctuic Ann Powen Co>u ANY ltiruuoxn.Vueoisir unent June 9,1992 s
U. S. Nuclear Regulatory Commission Serial No.92-367 Attention: Document Control Desk NAPS /JHt/TAH:R5 Wasnington, D. C. 20555 Docket Nos. 50-338 60 339 License Nos. NPF-4 NPF 7 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION 'JNITS 1 AND 2 W.S.Pj:CTION REPORT NOS. SQ-338/92-10 AND 50 339/R?d1D RESPONSE TO THE NOTICE OF VIOLATION We have reviewed your letter of May 15,1992, which referred to the inspection conducted at North Anna Power Station from March 22,1992, through April 18,1992, and reported in inspection neport Nos. 50-333/92-10 and 50 339/9210. The letter also transmitted notice of a violation that was identified during the inspection. Our response to the Notice of Violation is attached, if you have any further questions, please contact us.
Very truly yours, q;
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L W. L. Stewart Senior Vice President - Nuclear Attachment oc: IJ. S. Nuclear Regulatory Commission 101 Marietta Street, N.W.
Suite 2900 Atlanta, Georgia 30323 Mr. M. S. Losser NRC Senior Resident inspector North Anna Power ' tation I
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- Docket Nos, 50 338&339 SerialNo.
92+367
Attachment:
Pa00 t of 2
- RESPONSE TO THE NOTICE OF VIOLATION jNSPECTION REPORT NQS. 50-338/9210 AND 50-339/9210 NRC COMMENT-During a NRC inspection conducted on March 22 April 18,1992, a violation of NRC i
requirements was identified. In accordance with the " General Statement of Policy and Procedure for NRC Enforcement-Actions," 10 CFR Part 2, Appendix C, (1991), the violation is listed below:
Technical Specification 4.5.2.h requires, as a condition of operability, that for high:
head safety injection lines with a single pump running, the sum of the injection line flow rates, excluding the highest flow rate ir, greater than or equal to 384 gpm.
Contrary to the above, testing performed 'on' April 10,1992, demonstrated that the
-y sum of the injection line flow rates, excluding the highest flow rate was 347 gpm because of incorrectly positioned _hranch line throttle valves and that this condition:
existed while the system was required to be operable.
Thic is a Severity Level IV Violation (Supplement 1).
RESPONSE TO THE NOTICE OF VIOLATION 1.
ADMaSSION OR DENIAL OF THE ALLEGED VIOLATION The violation is correct as stateo.
l 2.
REASON FOR THE VIOLATION The violation was caused by the repositioning of a branch line throttle valve-following the safety injection flow calance test that was conducted during the 1090 Unit 2 refueling outage. Following testing in 1990, stem height measurements of
- the safety injection branch line throttle valves were taken and locking devices were installed to maintain their position. A question later arose as to_whether the-
"as (oft" position of the throttle valves had been inadvertently altered during thei installation of the locking devices. Personnel were dispatched to measure the-stem height positions. These' measurements were compared to the-previously recorded measurements and were in agreement. During the 1992 flow test, conducted with state of the art ultrasonic flow instrumentation, it was determined that a very small amount of branch line throttle valve _ movement could produce ficws outside the narrow safety injsetion flow acceptance criteria range provided by Technical Specification 4.5.2.h.
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Docket Nos. 50-3388339-Serial No.
92 367
Attachment:
Page 2 of 2
- i 3.
CORRECTIVE STEPS WHICH HAVE BEEN TAKEN AND THE RESULTS ACHIEVED The throttle valves in the safety injection system branch lines were readjusted to establish flow in accordance with the Techn! cal Specification requirements. The two cold leg safety injection branch lines with the lowest flow rates were verified to have a total flow rate greater than or equal to 384 gpm, as required by Technical Specification 4.5.2.h. The hot leg safety injection flows were within Technical Specification limits and did not require adjusting.
Following readjustment of the valves, locking valve stem covers were installed on the Unit 2 throttle valves. The keyholes in the cover locks were then injected with a sealant mate: # to ensure that the position of the valves are not disturbed during-the performance of routine valve lineups or other evolutions. Because these covers restrict access to the valves, but do not directly constcain them, their installation does not result in inadvertent valve movement, The physical attributes of the throttle valves in-the safety injection system branch lines make them.
resistant to random movement caused by vibrations, or system pressure and temperature variations.
An assessment of the low safety injection flows was performed, and it was determined that the acceptance criteria of 10CFR50.46 continued to be satisfied.
4.
CORRECTIVE STEPS WHICH WILL BE TAKEN TO AVOID FURTHER VIOLATIONS
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Locking valve stem covers will continue to be used for securing the throttle valves in the safety _ injection system branch lines _instead of the locking cap nuts previously discussed.
A Technical Specification change is also being considered, based on the latest safety analysis, to expand the acceptance range for the safety injection system branch line flow rates.
5.
THE DATE WHEN FULL COMPLIANCE WILL BE ACHIEVED Full compliance has been achieveo.
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