ML20004C635
| ML20004C635 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 05/29/1981 |
| From: | Curtis N PENNSYLVANIA POWER & LIGHT CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, PLA-819, NUDOCS 8106040359 | |
| Download: ML20004C635 (4) | |
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. TWO NORTH NINTH STREET, ALLENTOWN, PA.18101
' PH ON E: (215) 770-5151 NORMAN W. CURTis
. %ce President.Ent,ineenng & Construction. Nuclear,
7745301 May 29, 1981
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b Mr. Boyce H.' Grier Director, Region I D
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0 U.'S. Nuclear Regulatory Commission 8#
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-King of Prussia, PA 19406 4
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SUSQUEHANNA STEAM ELECTRIC STATION
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INTERIM REPORT OF A DEFICIENCY INVOLVING PACIFIC SWING CHECK VALVE FAILURE ER's 100450/100508 FILES 840-4/900-10 PLA-819
Dear Mr.'Grier:
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This letter serves to confirm information provided by telephone to NRC Region I Reactor Inspector, Mr. L. Narrow, on April 10, 1981 by Mr. A. R. Sabol of PP&L.
Mr. Narrow was advised that the SSES Unit #1 RCIC Turbine Exhaust Line Check Valve, manufactured by MCC/ Pacific Valve Co. had failed during.
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functional testing. This deficiency is considered reportable under the provisions of 10 CFR 50.55(e).
The attachment to this letter contains a description of the deficiency, its cause, safety implications and the corrective action planned. This information is submitted pursuant to the provisions of 10 CFR 50.55(e).
Since the details of this report provide information relevant to the reporting requirements of 10 CFR 21, this correspondence is considered to also discharge any formal responsibility PP&L ma? have for reporting in compliance thereto.
We expect to provide a final report on this condition by July 31, 1981. We trust the Commission will find this information to be satisfactory.
Very truly yours, V
N. W..Curtis Vice President-Engineering & Construction-Nuclear RAS:sab P1N N SYLV ANI A POWER & LIG HT COMP ANY (8:10.6 0 //t%-
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- r' L'MrC.Boyce[H' - Grier '.
- - May - 29, - 1981 :
- cc _ Mr. ' Victor l Stello -- (15) -
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-Director-Office of Inspection'.& Enforcement-
- U.-S. Nuclear Regulatory Commission
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'Wasnington, D.C..20555'.
- Mr. G. ' Mcdonald,j Director 1(1) 4
. Office cf Manacament:Information & Erogram Control-
' U. S.";'4uclear mi Commission'~
' Washington, D.
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- Mr. Gary Rhoads.-
U..S.. Nuclear Regulatory Commission'
'P.O. Box.
- Shickshinny, PA 18655 i
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-INTERIM ~ REPORT-?A
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^ PACIFIC; SWING' CHECK:
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- VALVE DISC FAILURE
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UNITS 1 &.
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-ATTACHMENT.TO-PLA-819 a-v.
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INTERIM REPORT-
- 1.
Description of Problem -
Bechtel NCR-7166Lidentified that the~ RCIC Turbine Exhaust Line Check J-Valve failed during ISG functional testing. The stud (integrally cast with the disc) which attached the disc to the valve hinge arm broke
. off during. system testing. The valve is. a 10 inch,, nuclear class 2, carbon stee~.,150 # rated swing check manufactured by MCC/ Pacific Valve
- Co. The disc is a casting made of. SA--351, grade CA-15 material, (martensitic
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stainless steel)..
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....' 2~.1 Cause of Deficiencv
-f Two unrelated c.onditions contributed to the failure. First, erratic l-steam flow co..>itions ~ caused the valve disc to cycle violently open and 4
closed. 'As?a result, the end of the disc stud gradually wore a hole in
- the valve bonnet which served as the stop. This additional travel allowed l
the disc to impact against the valve body due to a lack of clearance. The loads ~ and stresses experienced by the disc resulted in a disc stud fracture.
- I Sec 'dly, the stud broke off in a brittle manner, which is abnormal for properly heat treated CA-15 material.
3.
Analysis of Safety Imolication The safety function of the valve is to provide short term containment isolation during an accident condition. The failure is considered a significant deficiency that is repertable undez 10CFR50.55(e).
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Corrective Action 3
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Bechtel Engineering is currently studying the failure to determine if i
a' system design problem exi::ts. They are working with plants that have i
e had air.ilar problems in the RCit system and with General Electric design aengineers.- Modifications will be performed as deemed necessary.
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.. To determine i.f metallurgical irregularities exist, PP&L has sent the i
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subject disc to an independent testing lab for metallurgical examination.
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If the test results indicate a caterial problem, Bechtel will work with l
Pacific Valve Co. to determine if the material problem is isolated to the 4
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subject disc or if other check valve discs made of SA-351, grade CA-15 l
naterial, are affected. All Pacific check valve discs for which unacceptable
[<e mechanical properties are identified will be replaced.
l 5.
Final Recort A final report will be released upon resolution of all issues.
It is f
anticipat d that the final report will be issued by July 31, 1981.
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