ML20127F686
| ML20127F686 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 01/14/1993 |
| From: | Dromerick A Office of Nuclear Reactor Regulation |
| To: | J. J. Barton GENERAL PUBLIC UTILITIES CORP. |
| References | |
| TAC-M80558, NUDOCS 9301200336 | |
| Download: ML20127F686 (3) | |
Text
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January 14, 1993 Docket No. 50-219 Mr. John J. Barton Vice President and Director GPU Nuclear Corporation Oyster Creek Nuclear Generating StTtion Post Office Box 388 Forked River, New Jersey 08731
Dear Mr. Barton:
~
SUBJECT:
REVIEW 0F IGSCC EXAMINATIONS IN CAST STAINLESS STEEL COMPONENTS (TAC NO. M80558)
The staff has reviewed the October 2,1992, submittal of GPU Nuclear Corporation (GPUN).
In it, GPUN addressed concerns we raised in our August 25, 1992 safety evaluation of examinations for intergranular stress corrosion i
cracking (IGSCC) and weld repairs. We had concluded that GPUN adequately addressed IGSCC in conformance with Generic Letter 88-01. However, we had requested that GPUN (1) commit to a walkdown inspection of piping supports to ensure that set points and air gaps are properly adjusted, and (2) enlain why current examination methods such as the refracted longitudinal wave techniques would not yield meaningful results in inspecting for IGSCC in five recirculation pump casing-to-suction-elbow welds.
GPUN agreed to perform walkdown inspections during the upcoming 14R refueling outage and thus address our first concern.
As for the ultrasonic inspections, GPUN explained why it believes current methods would not give meaningful results.
GPUN cited studies by the EPRI NDE center and others that concluded that current methods are unreliable.
Cast grain structures vary widely and affect ultrasonic wave propagation through the material. A better understanding of how grain stt uctures affect wave propagation is needed before changes to equipment can be made to improve the reliability of detecting defects. Work is continuing in this area and GPUN is keeping informed of new developments.
If a reliable method is developed, GPUN will reconsider performing these examinations.
Instead, GPUN intends to inspect the pump consistent with ASME Code Case N-481, " Alternate Examination of Cast Austenitic Pump Casings,Section XI, Division 1."
This case describes examinations acceptable in lieu of volumetric examinations.
Item (c) of the case would apply risual examination of the internal surfaces whenever a pump is dissembled for maintenance.
The NRC staff had discussed this option with GPUN earlier; GPUN has documented its commitment in its letter of November 25,
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'l Mr. John J. Barton We agree that ultrasonics would not yield reliable results and applying the Code case is an acceptable alternative.
Therefore, we consider this issue resolved.
Sincerely, Original signed by Alexander W 9romerick, Senior Project Manager Project Directorate I-4 Division of Reactor Projects - 1/II Office of Nuclear Reactor Regulation cc:
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DATE 0FFICIAL RECORD COPY-1 i
Document Name:
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Mr. John J. Barton Oyster Creek Nuclear GPU Nuclear Corporation Generating Station
-cc:
Ernest L. Blake, Jr., Esquire Resident Inspector Shaw, Pittman, Potts & Trowbridge c/o U.S. Nuclear Regulatory Commission 2300 N Street, NW.
Post Office Box 445 Washington, DC 20037 Forked River, New Jersey 08731 Regional Administrator, Region I Kent Tosch, Chief U.S. Nuclear Regulatory Commission New Jersey Department of 475 Allendale Road Environmental Protection King of Prussia, Pennsylvania 19406 Bureau of Nuclear Engineering CN 415 BWR Licensing Manager Trenton, New Jersey 08625 GPU Nuclear Corporation 1 Upper Pond Road Parsippany, New Jersey 07054 Mayor Lacey Township 818 West Lacey Road Forked River, New Jersey 08731 Licensing Manager Oyster Creek Nuclear Generating Station Mail Stop:
Site Emergency Bldg.
Post Office Box 388 Forked River, New Jersey 08731