ML19323D831
| ML19323D831 | |
| Person / Time | |
|---|---|
| Site: | Atlantic Nuclear Power Plant  |
| Issue date: | 04/29/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Collier A OFFSHORE POWER SYSTEMS (SUBS. OF WESTINGHOUSE ELECTRI |
| References | |
| NUDOCS 8005220406 | |
| Download: ML19323D831 (1) | |
Text
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'o UNITED STATES l'
NUCLEAR REGULATORY COMMISSION g
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.. r REGION II b[
101 MARIETTA ST., N.W., SulTE 3100 o,
ATLANTA, G EORGIA 30303 o
APR 2 91980 In Reply Refer To:
RII:JP0 (150-437,-
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Offshore Power Systems Attn:
A. R. Collier, President P. O. Box 8000 Jacksonville, Florida 32211 Gentlemen:
The enclosed IE Information Notice No. 80-16 provides information on 6
two instances of main steam swing check or isolation valves binding 'ue to shaft packing.
Sincerely, i
D f t.
James P. O'Rei ly I
Director
Enclosures:
1.
IE Information Notice No. 80-16 2.
Recently Issued IE Information
,.j Notices
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UNITED STATES 8002280667 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, DC 20555 April 29, 1980 l
IE Information Notice No. 80-16
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SHAFT SEAL 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 7
I disassembly of the main steam isolation valves at Indian Point 2, it was 1
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 of these valves in all four loops and verifying that valve disc movement is not restricted.
During testing in the hot standby mode at the Trojan Nuclear Plant on April 15, 1980, three of the four main steam line isolation va:ves 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 a re being investigated by the licensee.
l This Information Notice is provided as notification of a possible significant It is expected that the recipients will review the informa, tion for matter.
possible applicability to their facilities and appropriate corrective action taken.
No written response to this IE Information Notice is required.
i
o IE Information Notice No. 80-16 Enclosure April 29, 1980 RECENTLY ISSUED IE INFORMATION NOTICES Information Subject Date Issued To Notice No.
Issued 80-16 Shaft Seal Packing Causes 4/29/80 All power reactor Binding in Main Steam Swing facilities with an OL Check and Isolation Valves or CP 80-15 Axial (Longitudinal) 4/21/80 All light water reactor Oriented Cracking In facilities holding power Piping reactor OLs or cps 80-14 Safety Suggestions From 4/2/80 All power reactor Employees facilities with an OL or CP 80-13 General Electric Type SBM 4/2/80 All light water reactor Control Switches - Defective facilities holding power Cam Followers reactor OLs or cps 80-12 Instrument Failure Causes 3/31/80 All hulders of power Opening of PORV and Block reactor OLs and cps Valve 80-11 General Problems with ASCO 3/14/80 All holders of Reactor Valves in Nuclear Application OL, CP, fuel fabrica-Including Fire Protection tion and processing Systems facilities 80-10 Partial Loss of Non-Nuclear 3/7/80 All power reactor Instrument System Power facilities holding Supply During Operation OLs and cps 80-09 Possible Occupational 3/7/80 All holders of Health Hazard Associated power reactor OLs with Closed Cooling Systems and near term cps 80-08 The States Company Sliding 3/7/80 All power reactor Link Electrical Terminal facilities with an OL Block or a CP 80-07 Pump Shaft Fatigue Cracking 2/29/80 All Light Water Reactor Facilities holder power reactor OL.s and cps
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