ML20078R765
| ML20078R765 | |
| Person / Time | |
|---|---|
| Site: | McGuire  |
| Issue date: | 12/15/1994 |
| From: | Mcmeekin T DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 94-06, 94-6, NUDOCS 9412270212 | |
| Download: ML20078R765 (3) | |
Text
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i-T.C of6litxa DukeIbwer Company hicGwre Nuclear Generation Department Vice President i
12iOOllagen ferryRoad(kfG0lW)
(704)87M800
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Hunterwille. NC28078MS (704)87M809 fax i
1 DUKEPOWER December 15,1994 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555
Subject:
McGuire Nuclear Station Unit 1 Special Report No.: 94-06 Pro $lem investigation Process No.: 1-M94-1387
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i Gentlem Attached for your Information is Special Report No. 94-06, pursuant to requirements of Technical Specification 3/4.5.3, Emergency Core Cooling Systems (ECCS). This report documents performance of testing in an effort to reduce ECCS check valve leakage where flow was knowingly initiated into the RCS "B" Cold Leg Loop from the FWST to assist in the proper seating of these valves. The only concern in this evolution is a potential increase in fatigue usage of the associated piping; however, under the controlled conditions of the evolution, the resulting increase in usage was detarmined to be insignificant and acceptable. This item is considered to be of no significance with respect to the health and safety of the public.
Very truly yours, u
T.C. McMeekin RJD/bcb Attachment cc:
Mr. S.D. Ebneter INPO Records Center Administrator, Region 11 Suite 1500 U.S. Nuclear Regulatory Commission 1100 Circle 75 Parkway 4
101 Marietta St., NW, Suite 2900 Atlanta, GA 30339 Atlanta, GA 30323
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Mr. Victor Nerses Mr. George Maxwell U.S. Nuclear Regulatory Commission NRC Resident inspector Office of Nuclear Reactor Regulation McGuire Nuclear Station Washington, D.C. 20555 9412270212 941?*,5 PDR ADOCK 05C00369 9
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0.L Walsh (EC11C)
Zack Taylor (CNS)
G.A. Copp (EC050)
J.l. Glenn (MG02ME)
P.A. Herran (MG01VP)
R.C. Norcutt (MG01WC)
S.G. Bonesole (ONS Reg Compliance)
G.H. Savage (EC06E)
G.B. Swindlehurst (EC11-0842)
M.S. Tuckman (EC07H) 1 R.F. Cole (EC05N)
D.B. Cook (EC13A)
Tim Becker(PB02L)
P.M. Abraham (EC081)
Bruce Caldwell(MG01VP) s V. Wilkie (ONO3SR)
D P. Kimball(CN05SR)
NSRB Support Staff (EC05N)
Kay Crane (MG01RC)
Rich Casler (EC05N)
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5 DUKE POWER COMPAMY McGUIRE NUCLEAR STATION SAFETY REVIEW GROUP SPECIAL REPORT This Special Report is due to requirements of Technical Specification 3/4.5.3, Emergency Core Cooling Systems. This report concerns'an intentional increase of fatigue usage to NI system piping by manually initiated flow through the "B" Cold Leg from the FWST during testing for valve 1NI-71, On October 12, 1994. This occurance is documented on problem investigation process (PIP) 1-M94-1387 Special Report No.: 94-01 Date Of Report: December 14, 1994 On October 4, 1994, testing was initiated on several Safety Injection.
(NI) system check valves which had been worked on during the Unit 1 End Of Cycle (EOC) 9 refueling outage.
This testing was initiated as a proactive effort to decrease check valve leakage. Testing of the.yalves was accomplished using procedures PT/1/A/4200/08B, Reactor Coolant %(NC)
Pressure Isolation Valve Leak Rate Test, and PT/1/A/4206/09, NI Check Valve Movement Test. The initial testing began with the NC system'at approximately 300 psig and 130 degrees F (water solid conditions).
Initial alignment and testing for NI system to the Cold Legs was performed successfully. Valve 1NI-71, Accumulator 1B Discharge Check Valve, did not meet the leak rate test acceptance criteria apparently due to improper seating.
On October 6, 1994, maintenance was performed on valve 1NI-71.
Following the maintenance the valve was pa tially stroked.
Subsequent leak testing again revealed leak-by in excess of accer.ance criteria.
4 Testing continued over the next several days in an ef rt to determine a i
cause of the leak-by and to see if the valve would seat properly at a higher NC system pressure. This type of testing is consistent with similar cases within the industry. No significant change was noted from the previous testing.
On October 12, 1994, venting alignment testing was attempted but it also resulted in no decrease in the flow through the valve.
In an effort to get the valve to seat properly, a restricted change to procedure PT/1/A/4206/09, NI Check Valve Movement Test, was prepared and performed. The purpose of the change was to intentionally manually initiate an NI system injection into the "B" Cold Leg and thereby cause the valve to seat properly. This test was performed in Mode 4 (Hot Shutdown) with NC system Tave > 325 degrees F.
It' isolated the A, C, and D Cold Leg NI system Injection Lines, with Operations personnel able to realign NI Safety Injection within 30 minutes.
Flow was injected through valve 1NI-71 by routing NI system pump discharge through the normal two inch line to Loop B.
A vent path was established to the test header. These efforts to swing the valve closed had no impact on the leak-by.
NC system Tave was at 337.9 degrees F during the injection.
Injected flow was 170 gpm.
There were three separate injections, each lasting for 15 seconds, 15 seconds, and 30 seconds, respectively and stopped by closing the isolation valve or by stopping the NI system pump.
The total accumulated actuation cycles to dato for the affected NI system nozzle is 9.
The current value of the usage factor for tha affected NI system nozzle is < 0.70.
i The results of this proactive testing suggested the valve would continue to leak at higher pressures and, the decision was made that startup of Unit 1 should be discontinued to repair the valve.
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