ML19350B269
| ML19350B269 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 02/27/1981 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Rich Smith VERMONT YANKEE NUCLEAR POWER CORP. |
| References | |
| NUDOCS 8103200195 | |
| Download: ML19350B269 (1) | |
Text
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UNITED STATES 8 '$,.,
g NUCLEAR REGULATORY COMMISSION j
REGION I 631 PARK AVENUE y
KING oF PRUSSIA, PENNSYLVANIA 19406 g***** e
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Docket No. 50-271 FEb 2,1981 N
y, R(((//h/ \\a Vermont Yankee Nuclear Power Corporation N
6] "'*',I4/,' f '7 gp3 ATTN: Mr. Robert L. Smith
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/9g7 A Licensing Engineer r-1671 Worcester Road Framingham, Massachusects 01701 4
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Gentlemen:
The enclosed IE Information Notice No. 81-04, " Cracking in Main Steam Lines" is forwarded to you information.
No wr> +.en response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely, WG-k s l vl. -
e H. Grier 1 rector
Enclosures:
1.
IE Informatien Notice No. 81-04, with 2 :ttachments CONTACT:
L. E. Tripp (215-337-5282) cc w/encis:
Mr. Warren P. Murphy, Plant Superintendent Mr. W. F. Conway, Vice President ar.d Manager of Operations Mr. J. E. Griffin, President Mr. L. H. Heider, Vice President h
8108200
SSTNS No.: 6835 Accession No.:
8011040265 IN 81-04 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 February 27,1981 IE Information Notice No. 81-04:
CRACXING IN MAIN STEAM LINES Description of Circumstances:
The Virginia Electric Power Company promptly notified the NRC on February 23, 1981 that a radiography 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 header and 30-inch main steam line of Steam Generator "A".
This piping connection is located outside the containment penetration immediately upstream 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 c' clock to 8 o' clock position. Cracking was also observed in the weld counterbore at the oppositt end of the T-fitting during visual examination of the piping interio.
Radio-graphic examination of "B" and "C" main steam line T-fitting welds disclosec'.
i crack indications at similar locations.
1 1
Metallurgical specimens of the cracking were trepanned from the T-fitting l
of the "A" main steam line for analysis.
Controlled excavatim and depth measurements of the crack at its mid-length indicated a crack tepth of about 0.090" in this location. The cause of cracking has not yet brcn established.
VEPCC N s planned an ultrasonic examination.of similar weldments in Surry Unit 2 main team lines utilizing " Hot Piping" ultrasonic techniques.
Preparations are also being made to ultrasonic examine similar weldments 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 revie by the NRC staff.
It is expected that recipients will review the infor.aation for possible applicability to their plants.
For those plants havirj
.1 are currently in a refueling e.. 9 that a ultrasonic and/or radiogr
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DUPLICATE DOCUMENT counterbore areas of the T-fitti operations, unless some current Entire document previously is available.
entered into system under:
%O/10//0245 m
No. of pages:
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