ML20004F811
| ML20004F811 | |
| Person / Time | |
|---|---|
| Site: | Cooper, Arkansas Nuclear, Fort Calhoun, Fort Saint Vrain  |
| Issue date: | 03/04/1981 |
| From: | Madsen G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| NUDOCS 8106220458 | |
| Download: ML20004F811 (1) | |
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UNITED STATES
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NUCt. EAR REGULATORY COMMISSION REGloN IV g
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MEMORANDUM FOR: Those Listed Below FROM:
G. L. Madsen, Chief, Reactor Projects Branch, RIV
SUBJECT:
IE INFORMATION NOTICE NO. 81-04 Subject IE Infomation Notice has been sent to the following licensees. A copy is attached for your infomation.
Arkansas Power & Light Company ANO-1 & 2 (50-313, 50-368)
Nebraska Public Power District Cooper Nuclear Station (50-298)
Omaha Public Power nistrict Ft. Calhoun Nucl u r Station (50-285)
Public Service Company of Colorado Fort St. Vrain (50-267)
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'G. L. 4.adsen, Chief Reactor Projects Branch
Attachment:
As stated DISTRIBUTION:
IE FILES MPA/DTS CENTRAL FILES
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SSINS No.: 6835 Accession No.:
8011040265 UNITED STATES NUCLEAR REGULATORY CCMMISSION OFFICE OF INSPECTION AND ENFORCEMENT
'4ASHINGTON, D.C. 20555 IE Information Noticc 'lo. 31-04 February 27, 1981 Page 1 of 2 CRACKING IN MAIN STEAM LINES Descriotion of Circumstances:
The Virginia Electric Power Company promotly notified the NRC on Feoruary 23, 1981 that a radiography examination, during the ongoing steam generator replacement outage at Surry Unit 1, had revealed a lengthy crack indication in tne I.O. countercore area of a welcment on the in-line "T" fitting which 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 ccnnection is located outside the containment penetration f aneciately uostream 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 about 120 F around the fitting counterbore between the 4 o' clock to 3 o' clock position.
Cracking was also observed in the weld countercore at the opposite end of the T-fitting during visual examination of the piping interior.
Radio-
. wmc examination of "3" 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.
Controllec excavation and deptn measurements of the crack at its mid-length indicated a crack depta of about 0.090" in this location.
The cause of cracking has not yet been established.
VEPCO has planned an ultrasonic examination of similar welcments in surry Unit 2 main steam lines utilizing " Hot Piping" ultrasonic tecnnicues.
Precarations are also being mace to ultrasonic examine similar welcments at North Anna Unit 1, currently in cold snutcown for refueling.
Recommencation to Licensees:
$de 44mtion is crovided as an early notification of a significant safety g? 5 t 9/ 7 m : '
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or possible acclicacility to Oneir
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- NRC staff.
It is exoected tnat m
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main steam line configurations wnica h
DUPLICATE DOCUMENT t recair outage, it is rec:mmenced I'
- amination of :ne tnree welcs anc f"
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entered into system under:
3r assurance of oicing integrity 30ll N o Q 7 ANo No. of paces:
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