ML20003G362
| ML20003G362 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 04/21/1981 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8104290149 | |
| Download: ML20003G362 (3) | |
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[D Commonwealth Edison
) One First National Plaz3, Chicigo. Illinois
[
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( O }~ Address Reply to: Post Office Box 767 Chicago Illinois 60690 j
April 21, 1981 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC. 20555
Subject:
Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 Utilization of ASME Code Case N-292 NRC Docket Nos. 50-454, 50-455, and 50-457
Dear Mr. Denton:
l This is to inform you of our intent to make use'of ASME Coce Case N-292, regarding deposition of wela metal prior to preparing ends for welding.
A copy of the approved Code Case is
]
attached.
This Code Case was approved by the ASME Council on January 15, 1981, with no comment by the NRC representative.
It allows more efficient construction by reducing rework and materials wa. stage.
Commonwealth Edison requests that the NRC staff acknowledge i
acceptability of this Code Case for immediate use at Byron and Braidwood Stations.
One (1) signed original and thirty-nine (39) copies of this letter and the attachment are enclosed for your use.
Very truly yours, Yo T. R. Tramm Nuclear Licensing Admin.istrator Pressurized Water Reactors l
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Case N-292 Depositing Weld Metal Prior to Preparing Ends for Welding Section III, Division 1, Classes 1, 2, and 3 Construction.
Inquiry:
May weld metal be deposited on either or both the inside and outside surfaces at the ends of Section III, Division I, Classes 1, 2, and 3 items prior to final counterboring, sizing, or grinding in order to provide for the required alignment and thickness at the end preparation for welding?
Reply:
It is the opinion of the Committee that weld metal may be deposited on either or both the inside and outside surfaces at the ends of Section III, Division, Classes 1, 2, and 3 items prior to final counterboring, sizing, or grinding to provide for the required alignment and thickness of end preparations for welding provided the following requirements are met:
1.0 The weld metal shall be deoosited in accordance with the requirements of NB 4000, NC 4000, or ND-4000, as applicable.
PWHT of the weld deposit, when required, may be performed prior to final weld preparation, or may be performed concurrently with PWHT of the completed weld.
The amount of weld metal which may be dehosited is 2.0 limited in width to the larger of three times the nominal base material thickness or one inch from the end of the final weld end preparation, and the total thickness of deposited weld metal after final weld end preparation is limited to one-fourth the nominal base material thickness, or one-half inch maximum, whichever is greater.
Amounts of deposited weld metal which exceed these criteria shall be considered repair of base material and shall meet the requirements of NB-4130, NC 4130, or ND 4130, as applicable.
e 3.0 The deposited w3ld metal on Class 1 and Class 2 items shall be examined by radiography and in addition, Class 1 item shall be examined by the r.agnetic particle or licuid penetrant method.
The examina tion procedures and acceptance standards shall be in accordance with the requirements of NB-5000 and NO-5000 as applicable.
The radiographic examination may be performed either before or aftgr final weld end preparation or it may be pe* formed ccncurrently with the radiographic examination of the completed "eli.
M";nct*c 79rticle or licuid penet ant evtmin? tion c'c11 be perfor ed af ter final weld e-d preparation.
P00R ORENAL
s.
4.0 Af ter final weld end preparation, the deposited weld metal-en Class-3 items chall be examined by the magnetic particle or liquid penetrant method in accordance with.the requirements of ND-5000.
5.0 Use of this case.shall be noted on the Certificate Holder's Data Report Form.
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