ML20087M891
| ML20087M891 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 03/23/1984 |
| From: | Sinclair J VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| FVY-84-27, NUDOCS 8404020120 | |
| Download: ML20087M891 (2) | |
Text
e NERMONT YANKEE NUCLEAR POWER CORPORATION RD 5, Box 169, Ferry Road, Brattleboro, VT 05301
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ENGINEERING OFFICE March 23,1984 1671 WORCESTER ROAD FVY 84-27 FRAMINGHAM, MASSACHUSETTS 01701 TELEPHONE 617-872-8100 United-States Nuclear Regulatory Commission Washington, D. C. 20555 Attention:
Office of Nuclear Reactor Regulation Mr. Domenic B. Vassallo, Chief Operating Reactors Branch No. 2 Division of Licensing
References:
(a) License No. DPR-28 (Docket No. 50-271)
(b)- Letter, VYNPC to USNRC, FVY 84-22, dated March 13, 1984
Subject:
Vermont Yankee Recirculation and RHR Systems Weld Joint Inspection Program for the 1984 Refueling Outage
Dear Sir:
By Reference (b), we provided you with our plans for inspection of the recirculation and other reactor coolant boundary piping systems during our 1984 refueling outage. The purpose of this letter is to provide you with the enclosed replacement page for page one of the program. The page has been corrected, as indicated in the margin, to correct for a typographical error.
Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION J. B. Sinclair Licensing Engineer JBS/smh Enclosure cc: United States Nuclear Regulatory Commission Office of Inspection and Enforcement Region I 631 Park Avenue King of Prussia, PA 19406 Attention:
Mr. Robert Gallo h
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1.0 ULTRASONIC EXAMINATION CRITERIA 1.1 Scope Vermont Yankee intends to include 47 welds of the Recirculation l
and Residual Heat Removal Systems in the initial sample selected for examination during the 1984 refueling outage. The sample size has been determined based upon the following table:
Available percent in Number of Resultant Condition Population Initial Sample Examinations Overlays of repaired welds with IGSCC greater than or equal to 10%
of circumference 17 70*
12 Unrepaired welds with known IGSCC 12 100 12 Previously inspected welds with no indication of 26 20 7
Previously uninepected welds 60 20 16 Repaired welds with IGSCC less than 10% of the 5
0 0
circumference Total 47 Further distribution of the sample set will include assurance that the different pipe sizes are represented in the sample.
If additional ICSCC is detected in the samples representing the l-welds not previously inspected or the previously inspected welds I
not found to contain IGSCC, the sample size will be increased in accordance with the rules of IWB 2430 of Section XI as defined in L
I&E Bulletin 83-02.
l
- Ten overlayed joints are identical (sweepolet to riser). The overlay thickness is greater than 75% Tmin at each joint, greatly exceeding wall thickness required for design loads. The inspection approach here is to UT five of these joints (most affected by IGSCC) for weld metal integrity and bond to base metal. If no indications are found, the remaining five will not be re-inspected..
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