ML20077B467
| ML20077B467 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 05/03/1991 |
| From: | Fay C WISCONSIN ELECTRIC POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| CON-NRC-91-043, CON-NRC-91-43 GL-88-14, VPNPD-91-151, NUDOCS 9105140373 | |
| Download: ML20077B467 (2) | |
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VPNPD-91-151 NRC-91-043 May 3, 1991 U.
S.
NUCLEAR REGULATORY COMMISSION Document Control Desk Mail Station P1-137 Washington, D.
C.
20555 I
Ger.tlemen t DOCKETS 50-266 AND 50-101 RES101{SE TO GENERIC LETTER _0.0-14 INSTRUBEllT_6IR_EUPPLYPROBLEftS AEEECTING SAFETY-RELATED EQUlEBLill' POINT BEACH liUCLEAE_ELANT. UNITS 1 A111L2 In a letter dated July 27, 1989, we committed to replace Acahing instrument air vent valves in the Unit 1 Purge Supply and Exhauct System.
In a subsequent 1ctter dated June 18, 1990, we stated that this repair would be completed during the spring 1991 refueling outage.
You acknowledged this schedule in a letter dated January 9, 1991.
Because an adequate replacement valve is not available, we have made a procedural modification instead of a hardware change.
The subject vent valve is a cam-operated valve that supplies scaling air to the T-ring seals on the purge supply and exhaust isolation valves.
In the instrument air supply line, the vent valve is located between a check valve and the T-ring seals.
Since the vent valve leaks instrument air to the atmosphere, if l
the instrument air supply is lost, the valve would allow air to biced off the T-ring seals, potentially breaching containment l
integrity through the purge supply or exhaust line.
The subject vent valve is no longer produced, so we were unable l
to acquire an identical replacement valve.
The substitute valve, I
recommended by the manufacturer of the original vent valve, leaked during bench tests because it was not designed as an air tight valve, as we had thought.
We could not locate an adequate replacement vent valve.
l l
Because an adequate replacement valve was not found, a new procedure,
" Installation and Removal of Purge Valve Component Bypass Lines, RPM-150", has been instituted to assure the integrity of the l
9105140373 910503 0 $45' PDR ADOCK 05000266 PDR P
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U.
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Nuclear Regulatory Commission May 3, 1991 Page 2 Purge supply and Exhaust System.
Whenever containment integrity la required by Technical Specifications, the purge supply and exhaust isolation valves are locked shut, the Icaking vent valve is physically removed from the instrument air supply line, and instrument air is piped directly to the T-ring seals.
When the reactor is in a cold shutdown condition, and containment integrity is not required, the vont valves are replaced in the instrument air j
supply line to allow operation of the purge supply and exhaust isolation valves.
This procedure change insures that containment integrity will be maintained when required by Technical Specifications.
If you have any additional questions, please contact us.
Very truly yours, v-f
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0 C.W.
Fay i
Vice President Nuclear Power Copy to:
NRC Resident Inspector NRC Regional Administrator
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