ML19354E860
| ML19354E860 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/25/1990 |
| From: | Devine J GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 5000-90-1864, C311-90-2008, NUDOCS 9002020102 | |
| Download: ML19354E860 (2) | |
Text
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l GPU Nuolent Corporation
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Nuolear
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Middletown, Pennsylvania 17067 0191
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717 944 7621 TELEX 84 2366 Writer's Direct Dial Nurnber:
1 January 25, 1990 l
C311-90-2008 5000-90-1864 US Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
Dear Sir:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289-Proposed Alternative to ASME Boiler and Pressure Vessel (B&PV)
Code Section III Requirements Ref 1:
Babcock & Wilcox letter JHT/89-235 dated Noveinber 7,1989 to NRC, l
Taylor to Document Control Desk.
l Ref 2: NRC letter dated December 11, 1989 to Babcock & Wilcox, Richardson l
to Taylor.
It has recently been shown that Babcock & Wilcox (B&W) mechanical-steam generator plugs manufactured from certain heats of Alloy 600 are susceptible to' Primary Water Stress Corrosion Cracking (PWSCC).
Therefore, in accordance with 10CFR50.55(a)(3), GPUN is requesting approval for the use of B&W steam generator plugs manufactured with an alternate material. The alternate I
material is a nickel base alloy, ASME designation SB-166 (Alloy 690).
B&W has requested ASME and NRC approval (see reference 1) for the application of Alloy 690 material specifications SB-166, SB-167, SB-168 and SB-564 for ASME Code Section III repairs. Currently, ASME Code. Case N-474 permits the use of Alloy 690 for material specification SB-163, 1,
The ASME Code Main Committee has agreed to review the request.
It.is anticipated that the review will result in the inclusion of the above material specifications into an addenda to Code Case N-474.
Reference 2, which is an NRC response to Reference 1 on this subject.matier,:
indicates an understanding that an appropriate Code Case will be considered for final ASME approval in January, 1990.
It further states that if the appropriate Code Case has been approved by the ASME, the NRC can generically i
endorse its use for this application.
9002020102 900125
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PDR ADOCK 05000289 g0t P
PDC i
GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation
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-2 January 25, 1990 b000-90-1864 i
Alloy 690 has been shown to be superior to Alloy 600.
In particular, Alloy 690 I
has superior corrosion resistance to PWSCC. This particular feature can avert i
potential plug cracking concerns associated with Alloy 600 plugs, thus leading j
to improved safety.
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Because of the above mentioned safety improvement and the ASME precedence for the use of Alloy 690 in Code Case N-474, there is a high level of confidence in 1
the industry that Alloy 690 will be approved for steam generator plugs.
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Thus GPUN plans to procure and install, as needed, Alloy 690 steam generator plugs during the current BR refueling outage. The plugs will be in service prior to refilling of the steam generator primary side, which is currently i
planned for February 20, 1990.
NRC approval for the use of such plugs is requested.
Sincerely, d4..
J.'C.
C. DeVine, Jr.
Vice president & Director l
Technical Functions' l
JCD/EJP/emw
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cc:
R. Hernan I
i W. Russell i
J. Stolz I
F. Young i
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