ML18139A247
| ML18139A247 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 04/29/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Ferguson J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| NUDOCS 8005220342 | |
| Download: ML18139A247 (4) | |
Text
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e UNITED STATES NUCLEAR REGULATORY COMMISSION REGION II In Reply Refer To:
RII:JPO 50-338, 50-339
~40S; 50-405
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101 MARIETTA ST., N.W., SUITE 3100 ATLANTA, GEORGIA 30303 APR 2 9 1980 Virginia Electric and Power Company Attn: 'J. H. Ferguson Executive Vice President-Power P. O. Box 26666 Richmond, Virginia 23261 Gentlemen:
The enclosed IE Information Notice No. 80-16 provides information on two instances of main steam swing check or isolation valves binding due to
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t shaft packing.
Enclosures:
- 1.
IE Information Notice No. 80-16
- 2.
Recently Issued IE Information Notices
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Sincerely,
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James P. ~~
Director
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.Virginfa Electric and Power Company cc w/encl:
W.R. Cartwright, Station Manager Post Office Box 402 Minera~, Virginia 23117 P. G. Perry Senior Resident Engineer Post Office Box 38 Mineral, Yirginia 23117 W. L. Stewart, Manager Post Office Box 315 Surry, Virginia 23883
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UNITED STATES NUCLEAR REGULATORY COMMISSION
- oFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, DC 20555 April 29, 1980 SSINS No.:
6870 Accession No.:
8002280667 -
_ IE Information Notice No. 80-16 SHAFT ~EAL PACKING CAUSES BINDING IN MAIN STEAM SWING DISC CHECK AND ISOLATION VALVES Description of Circumstances:
Recently two instances of binding of swing check valves have occurred.
During disassembly of the main steam isolation valves at Indian Point 2, it was observed that all four reverse flow check valves were stuck at or near fully open.
These 28" valves are manufactured by Atwood & Morrill Co.
Investigation revealed that this condition was apparently caused by excessively tight shaft packing which did not allow free movement of the valve disc.
This condition was reported on January 31, 1980.
An evaluation determined that with the existence of the reported condition in event of a main steam line break upstream of a main steam isolation valve together with coincident single failure of a main steam isolation valve to close in another loop, the potential existed for blowdown of the contents of two steam generators.
Main steam line break analyses applicable to Indian Point 2 have been performed assuming blowdown of the contents of one steam generator and have not considered multiple steam generator blowdown.
Therefore, it is possible that the reported condition could have contributed to the exceeding of a safety limit as defined in the Unit 2 Technical Specifications if a main steam line break had occurred.
The reported condition was corrected by adjusting the packing bf these valves in all four loops and verifying that valve disc movement is not restricted.
During testing.in the hot standby mode at the Troj~n Nuclear Plant on April 15, 1980, three of the four main ste.am line isolation valves failed to close when manually actuated.
The cause of the occurrence was binding in the shaft packing.
The valve is air opened and is closed by gravity, steam flow and a small spring force; -the valves were manufactured by Atwood & Morrill Co.
The licensee believes that the valves would have closed during actual operations with steam flow in the line. The valves were repaired and tested satisfactorily.
Modifications to the valves to install air operators to help close the valves are being investigated by the licensee.
- This Information Noti_ce is provided as notification of a possible significant matter. It is expected that the rec:fpients will review the information for possible applicability to their.facilities and* appropriate.corrective action taken.
No written response* to this ;IE Information Notice is required *.
e IE Information Notice No. 80-16 April 29, 1980 Information Notice No. 80-16 80-15 80-14 80-13 80-12 80-11 80-10 80-09 80-08 80-07 RECENTLY ISSUED IE INFORMATION NOTICES Subject Date Issued Shaft Seal Packing Causes 4/29/80 Binding in Main Steam Swing Check and Isolation Valves Axial (Longitudinal) 4/21/80 Oriented Cracking In Piping Safety Suggestions From 4/2/80 Employees General Electric Type SBM 4/2/80 Control Switches - Defective Cam Followers Instrument Failure Causes 3/31/80 Opening of PORV and Block Valve General Problems with ASCO 3/14/80 Valves in Nuclear Application Including Fire Protection Systems Partial Loss of Non-Nuclear 3/7/80 Instrument System Power Supply During Operation Possible Occupational 3/7/80 Health Hazard Associated with Closed Cooling Systems The States Company Sliding 3/7/80 Link Electrical Terminal Block Pump Shaft Fatigue Cracking 2/29/80 Enclosure Issued To All power reactor facilities with an 01 or CP All light water reactor facilities holding power reactor OLs or CPs All power reactor facilities with an 01 or CP All light water reactor facilities holding power reactor OLs or CPs All holders of power reactor OLs and CPs All holders of Reactor OL, CP, fuel fabrica-tion and processing facilities All power reactor facilities holding OLs and CPs All holders of power reactor OLs and near term CPs All power reactor facilities with an OL or a CP All Light Water Reactor Facilities holder power reactor OLs and CP$
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