ML19350B273
| ML19350B273 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 02/27/1981 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Kay J YANKEE ATOMIC ELECTRIC CO. |
| References | |
| NUDOCS 8103200198 | |
| Download: ML19350B273 (1) | |
Text
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.A Docket No. 50-29 f.'
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Yankee Atomic Electric
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,I/lR.Z "o,001 A ATTN: Mr. James A. Kay h4
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Senior Engineer
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1671 Worcester Road y
N Framingham, Massad
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v Gentlemen:
The enclosed IE Information Notice No. 81-04, " Cracking in Main Steam Lines" is forwarded to you infor=ation.
No written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely, cfm/9-[k '
YbCvl -
e H. Grier sirector
Enclosures:
1.
IE Information Notice No. 81-04, with 2 attachments CONTACT:
L. E. Tripp (215-337-5282) cc w/encls:
H.-Autio, Plant Superintendent J. E. Tribble, President possou \\ s
SSINS No.: 6835 Accession No.:
8011040265 IN 81-04 UNITED STATES NUCLEAR REGULAf0RY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTGN, D.C. 20555 February 27,1981 IE Information Notice No. 81-04:
CRACKING IN MAIN STEAM LINES Description of Circumstances:
The Virginia Ele tric Power Company promptly notified the NRC on February 23, 1981 that a radiov.phy examination, during the ongoing steam generator replacement outage at Surry Unit 1, had revealed a lengthy crack indication in the I.D. counterbore area of a weldment on the in-line "T" fitting whi'ch connects the vertical run of 30-inch piping to the safety relief valve beacer and 30-inch main steam line of Steam Generator "A".
This piping connection is located outside the containment penetration immediately costream of the main steam isolation valve as shown in the attached sketch.
A visual and dye penetrant examination on the pipe I.D. surface of the weldment nearest the containment penetration established that the cracking extended 0
about 120 F around the fitting counterbore between the 4 o' clock to 8 o' clock position. Cracking was also observed in the weld counterbore at tSe opposite end of the T-fitting during visual examination of the piping interior.
Radio-graphic examination of "B" and "C" main steam line T-fitting welds disclosed crack indications at similar locations.
Metallurgical specimens of the cracking were trepanned from the T-fitting of the "A" main steam line for analysis.
Controlled excavation and depth i
measurements of the crack at its mid-length indicated a crack depth of about l
0.090" in this location.
The cause of cracking has not yet been established.
VEPCO has planned an ultrasonic examination.of similar weldment.
.a Surry Unit 2 i
main steam lines utilizing " Hot Piping" ultrasonic techniques.
Preparations are also being made to ultrasonic exaidna simil r valdments at North Anna Unit 1, currently in cold shutdown for refueling.
Recommendation to Licensees:
This information is provided as an early notification of a significant safety matter that is still under review by the NRC staff.
It is expected that recipients will review the information for possible applicability to their plants.
For those plants having
~
are currently in a refueling or that a ultrasonic and/or radiogr DUPLICATE DOCUMENT counterbore areas of the T-fitti operations, unless some current Entire document previously is available.
entered into system under:
R0//ovo24,5 Am No. of pages:
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