ML19254E086
| ML19254E086 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 10/04/1979 |
| From: | Moody D Maine Yankee |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| WMY-79-110, NUDOCS 7910310062 | |
| Download: ML19254E086 (3) | |
Text
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$,"dl ENGINEER;NG OFFICE WESTBORO, MASSACHUSETTS 01581 617-366-9011
"%J B.4.2.1 WY 79-110 October 4, 1979 United States Nuclear Regulatory Commission Office of Inspection and Enforcement Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 Attention:
Mr. Boyce H. Grier, Director
References:
(a) License No. DPR-36 (Docket No. 50-309)
(b)
I&E Letter to MYAPC deced June 25, 1979, I&E Bulletin No. 79-13 (c) MYAPC Letter to USNRC, Response to I&E Bulletin No. 79-13, WMY 79-11, July 13, 1979
Dear Sir:
Subject:
Report of Examinations Performed as Required by Bulletin 79-13 The following information is being submitted in response to the require-ments of item 6 of Reference (b).
During the periou 1 September 1979 through 25 September 1979, MYAPC per-formed examinations of 63 Main Feedwater pipe butt welds and 3 Auxiliary Feed to Main Feed branch connections. These welds included all feedwater line welds from the containment penetrations up to and including the pipe to nozzle and nozzle transition piece welds.
The pipe butt welds were radiographed per the requirements of item 1.a of Reference (b). The Auxiliary Feed connections were radiographed in a best effort basis. The Auxiliary Feed configuration is a 6 x 14 weldolet, wh ch is difficult to radiograph when no access to the pipe ID is available. To supplement the radiography, MYAPC performed a liquid penetrant examination and an ultrasonic examination on the branch connection welds. No evidence of unacceptable indications were found in the branch connection welds.
The requirement of item 2.a of Reference (b) to include examination of one pipe diameter downstream on the water feed line was performed on a best effort basis using ultrasonic examination. The downstream side of the Main Feed lines at the Auxiliary Feed connection is close to.the penetration through the crane wall.
The following is a summary of code unacceptable indications per NC-5000, which were found during the 79-13 examinations.
1235 CW 7910310 0 6 3 p
United States luclear Regulatory Commission October 4, 1979 Attention:
Mr. Boyce H. Grier, Director Page Two 1)
Downstream of Feedwater Check Valves -
1.1)
Feedwater line to #3 Steam Generator - weld #3 (fif th weld upstream of nozzle) showed lack of fusion in the root passes approximately 5/8" long. The indication is shown on the original construction radiograph.
Ultrasonic examination using ASME Sec. XI, App. III techniques indicated a 25% DAC signal at the max point of the indication. The indication would not be recordable during a nornal ISI.
2)
Upstream of Feedwater Check Valves 2.1)
Feedwater line to #3 Steam Generator 2.1.1)
Wald #13 indicated two (2) areas of lack of fusion. The area between 42 and 0 marker totaled 7/8" long.
The indication is 2 separate areas 1/4" long and 3/8" long with a 1/4" space. The area is found on the original radiograph with no change. An ultrasonic evaluation indicates a 60% DAC reflector at maxi =um position. This would be a recordable indication during ISI.
The area between 20-22 =arker indicated approximately 1/2" lack cf fusion. This indication can be found on the original radiogrcph. UT evaluations showed a 40 %
DAC spot.
This would not be recordable during an ISI.
2.1.2)
Weld 17 indicated lack of fusion or elongated slag 1/2" long.
The indication can be seen on the original radiograph. There is no c.hange from original. No UT was performed.
2.1.3)
Weld 19 indicated lack of fusion approximately 2" long (accumulated length of 2 indications). The indication is found on the original radiograph. UT evaluation shows less than 10% DAC with 45% shear exam and 20%
with a 70% shear exam. This indication would not be recordable during an ISI.
2.2)
Feedwater line to #2 Steam Generator. Weld 17 indicated a pore with possible star crack (crater crack). The indication is very fine but can be seen in the original radiograph. No UT evaluation was performed, because of the low probability of detection.
072
f-United States Nuclear Regulatory Con: mission October 4, 1979 Attention:
Mr. Boyce H. Grier, Director Page Three 3)
The indications described above originated from the initial welding. They are veld defects not considered or not detected during the original review of construction radio-graphy.
No change can be detected in any indication from the initial radiographs.
Maine Yankee evaluation considers the above welds acceptable for continued operation.
It will evaluate the repair of weld
- 13 on Feed line #3. The repair would be performed to eliminate continued monitoring of this indication.
4)
In accordance with item 1.c of reference b.)
a visual inspection of the piping supports for the three main feedwater lines was conducted. A total of 41 supports were inspected. All supports were found to be free of defects and to be in accordance with design documents.
We trust that you find this information satisfactory; however, should you require additional infor=ation, please contact us.
Very truly yours, MAINE YANKEE ATCMIC POWER COMPANY
/
Donald E. Moody Manager of Operations DEM/s=w 1235 073