ML19332E817
| ML19332E817 | |
| Person / Time | |
|---|---|
| Site: | McGuire  |
| Issue date: | 11/29/1989 |
| From: | Tucker H DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8912130017 | |
| Download: ML19332E817 (3) | |
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-November 29, 1989-i a
U.S. Nuclear Regulatory Commission LDocoment Control Desk Washington, DC '20555 n
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Subject:
McGutie Nuclear Station, Unit 1-r
-Docket No. 50-369 Diesel' Generator Special Report 4
- Gentlemen:
. Pursuant to Tachnic.al Specification'(T.S.) 6.9.2 as specified by T.S.
'4.S.1.1.3, find attached a special report concerning a Valid Failure on-
- Diosel Generator 1A.
If there are any questions, please contact S.E. LeRoy at (704).373-6233.
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,Very truly yours.-
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Attachment xc
'?tr. S.D. Ebneter, At.ministrator Mr. P.K. Ven Doorn, NRC U.S. Nuclear' Regulatory Commission Senior Resident Inspector
. Region II' McGuire Nuclear Station 101 Marietta St.,-NW, Suite 2900 Atlanta. Georgia '30323 Mr. D.S. Hood, Project Manager office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC ;20555
,INPO Records Center Suite 1500 1100 circle 75 Parkway R
Atlanta,' Georgia 30339 8912130017 BT1129
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' ADOCK 05000369
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Document Control Desk November-29, 1989
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McGuire Nuclear Station Diesel Generator 1A Special Report t-On October. 30, 1989 at 2100, while performing 'he pre / start checklist for:
t the monthly surveillance test (PT/1/A/4350/02A) on Diesel Generator (DG) 1A, an Operator discovered a large fuel oil leak from valve 1FD-83. The leak was isolated and DG 1A was declared inoperable. Work request (WR) no. 75111 was initiated to repair the leak.
1311s event is-considered a Valid Failure because ^f the discovery of a condition that would have caused a failure. This event is classified as start attempt no. 754 for DG 1A.
Valvo '1FD-83 (DG Fuel.011 Transfer P mp Back Pressure Relief) is a diaphragm valve manufactured by Viking Pump. The valve is located on the discharge of the fuel oil transfer pump to prevent the fuel oil storage tank from gravity draining into, and overflowing the fuel oil day tank.
The leak was from a vent hole above the diaphragm.
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Two replacement diaphragms were installed but in each case the' leak was still present. A new valve was obtained, disassembled, and its diaphragm assembly was installed in valvo 1FD-83. This action-stopped the leak.
. Vibration readings were taken on the fuel oil transfer pump and were satisfactory. On October 31, 1989, start attempts no. 755 and no. 756 were-performed at 1340 and 2015, respectively, to troubleshoot and verify the repair. On October 31,1989 at 2300, start attempt no. 757 was performed to verify the DG opernbility and perform the monthly surveillance test. Start
-attempt no. 757 was a Valid Success. DG 1A was then declared operable.
On November 6,1989, Operations personnel found valve 1FD-83 leaking. The i
Icak was very small and did not affect the operability of the DG, Work-request no. 140320 was initiated and the leak was closely monitored.- On November 8, 1989 Mechanical Maintenance (MNT) personnel-replaced valve 1FD-83 with a-new valve. No further leakage trom this valve has been noted.
Start attempt no. 758 was performed to verify the maintenance work. This start attempt was considered an Invalid Test because the run was intentionally terminated prior to operating DG one hour at greater than 50 percent load, s
The cause-of the valve failure was attributed to aging of the diaphragm material. The material loses elasticity in time and may also be affected by the fuel oil. The valve work request history indicated that leaks occurred in 1982 and 1986. 1
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November 29, 1989 MNT personnel also-determined that valve orientation may have an impact on the probability of leakage.
MNT personnel will evaluate the valve's maintenance program to include as necessary:
1.
Establishing a PM to periodically change out the diaphragms for each-DG applications and, 2.
Init.iating a Station Problem Report to change the valve -
orientaticn.
. Duke Design Engineering has been requested to perform a study on the feasibility of eliminating the fuel oil transfer pump and back pressure relief valve altogether.~ The study is to determine if a gravity fill situation can be setup from the underground storage tank to the day. tank.
Other options include elimination of the back pressure relief valve by installing a loop seal, and addition of a bypass line around the fuel oil transfer pump.
DG 1A has had one Valid Failure in the last 20 Valid Tests and 3 Valid Failures in the last 100 Valid Tests. On a unit basis, the combination of
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DG 1A and IB have had 5 Valid Failures in the last 100 Valid Tests. The surveillance test frequency remains monthly.
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