ML19262A392
| ML19262A392 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/07/1975 |
| From: | Lear G Office of Nuclear Reactor Regulation |
| To: | Arnold R METROPOLITAN EDISON CO. |
| References | |
| 750527, NUDOCS 7910260719 | |
| Download: ML19262A392 (3) | |
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GLear DJaffe Pet ropolitan Edison Compan, SATeets ATTU:
Mr.
R. C. Arnold Vice President - Generation TBAbernathy SVarga F. C.
Fax 542 ACRS (14) deadict. Pennsylvanie Ic693 Gray file extra cpc Gentlemen:
Adverse operating experience concerning main steam isolation valves (MSIVs) has been reported to the Cf tice of Inspection and Enf orcement ( OIS I') followine operat ional tests and spurious closures at various FKR stations.
In an ef fort to rain a better understandint of these events, Information Ecouest No. 74-2 was sent to all PWR stations by OI&E.
Be inforration thus obtained was used as input to a generic review ccaducted by the Division of Feector Licecsine.
During our review, we had the benefit of discussions with personnel repre-senting various valve manuf acturers and also with utility representatives whose facilities were af fected.
Durine tho course of our generic review we noted that a type of PSIV (a Y-pa t t e rn globe design) experienced f ailure during a rout ine plant startup. Cur review of this occurrence indicates that the ability of Y-pattern desirns to tolerate the dynamic forces associated with postulated steam line break conditions without significant mechanical danas;e must be reviewed.
Therefore, for Y-pattern globe valves, we require that analyses or test data to substantiate the performance of cach design under postulated accid ent conditiocs be submitted to us f or review.
AccordinF y, within 6 weeks followinF receipt of this letter, please provide tne l
infor=atioe recuested in the enclosure to this letter for Three Mile Island Unit 1.
Three sirned originals and thirty-sevec copies are receired.
This recuest for generic information was approved by CAO ur: der a blanket clearacce nu=ber E-16G2256 (EC072); this clearance expires July 31. 1977.
Siccerely.
tl ffs: '
Ceorge Lear. Chiet' O/
Operating B e a c t o rs Eranch ~3
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Form AEC-315 (Rev. 9-53) AICM 0240 W u. s. novranastwv rmurine orricas to74.sas.ies O
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Metropolitan Edison Company 2
PAY 2 7 1975
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G. F. Trowbridge, Esquire Shaw, Pittman, Potts, Trowbridge 6 Madden Barr Building 910 17th Street, N. M.
Washington, D. C.
20006 GPU Service Corporation Richard W. Heward, Project Manager Thomas M. Crimmins, Jr., Safety and Licensing Manager 260 Cherry Hill Road Parsippany, New Jersey 07054 Pennsylvania Electric Company Vice President, Technical 1001 Broad Street Johnstown, Penn3ylvania 15907 Mr. Weldon B. Arehart, Chairman Board of Supervisors of Londonberry Township 2148 Foxiana Road Middletown, Pennsylvania 17057 Miss Mary V. Southard, Chairman Citizens for a Safe Environment P. O. Box 405 Harrisburg, Pennsylvania 17108 Government Publications Section State Library of Pennsylvania Box 1601 (Education Building)
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9FOUEST FOR ADDITIONAL INFORMATION Y-PATTERN GLOBE AND S'n'ING-CHECK '1AIN STEAM ISOLATION VALVES 1.
Provide a su= mary of the analyses employed to confirm the integrity of the main steam isolation valves (MSIVs) under the dynamic loads associated with the postulated steam line breaks.
Include the following:
(a) The maximum calculated impact energy that will be sustained by valve internal elements and seating surfaces under the conditions imposed by postulated main steam line breaks for your station.
For Y-pat tern globe MSIVs, this response should address both forward and reverse flow.
(b) A summary of the mathods employed to calculate the energy levels given in response to (a) above.
(c) A su= mary of the maximum stress or strain calculated to occur in the principle elements of the valve assembly when subject to the impact forces characterized in (a) above.
(d) A summary of any other methods or criteria employed in conjunction with, or in lieu of, the information requested in (a), (b), and (c) above to provide assurance that the valve is adequately designed to perform the specified safety functions.
If the analysis has been performed by the valve manuf acturer or other party, reference to this document is satisfactory provided that the document is on file with the staf f.
2.
Describe any modifications incorpora t ed in, or to be incorpora t ed in,
the main steam isolation valves at your station.
Provide the present schedule for completion of this work.