ML19350A678
| ML19350A678 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 02/27/1981 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | William Jones OMAHA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 8103160644 | |
| Download: ML19350A678 (1) | |
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UNITED STATES POR:HQ
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NUCLEAR REGULATORY COMMISSION
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REGION IV NSIC
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$11 RYAN PLAZA CRIVE. SUITE 1000 ARLINGTON. TEXAS 76011 State February 27,198/
Cocket No.
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Omaha Public Powar District ATTN:
W. C. Jones, Division Manager -
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Gentlemen:
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This IE Informaticn Notice is provided as an early notificat cY a possibly significant matter and it is expected that recipients will review the informa-mation for possible applicability to their facility.
No response is requested at this time.
If further NRC evaluations so indicate, an IE Circular or Bulletin will be issued to further recommend or request specific licensee actions.
If you have questions regarding this matter, please contact the Director of tne appropriate NRC Regional Office.
Sincerely, e
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Karl V. Seyfrit Director
Enclosures:
1.
IE I.aformation Notice No. 81-04 2.
List of Recently Issued IE Information Notices
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- 5. C. Stevens, Manacer Fort Calhoun Station
?cs: Office Sox 98 crt Calhoun, 'lecraska 58102 81031eo#f p
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Accession No.:
8011040265 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 IE Information Notice No. 81-04 February 27, 1981 Page 1 of 2 CRACKING IN MAIN STEAM LINES Descriotion of Circumstances:
The Virginia Electric Power Company promptly notified the NRC on February 23, 1981 that a rad',ography examination, during the ongoin steam generator replacement outage at Surry Unit 1, had revealed a 15
.hy crack indication in the I.O. counterbore area of a weldment 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 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 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 the 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 measurements of the crack at its mid-length indicated a crack depth 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 tecnniques.
Preparations are also being made to ultrasonic examine similar welcments at North Anna Unit 1, currently in cold shutcown for refueling.
Reccmmencation 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 similar main steam line configurations wnich are currently in a refueling or extendec repair outage, it is recommenced that a ultrasonic and/or radiograonic examination of the tnree welds and countercore areas of the T-fittings be performed before resumption of operations, unless some current basis for assu-ance of piping integrity is availaole.
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IN 81-04 February 27, 1981 Page 2 of 2 No response to this notice is requested at this time.
If you have any questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Attachment:
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IE Information Notice No. 81-04 February 27, 1981 LISTING 0F RECENTLY ISSUED IE INFORMATION NOTICES Information Subject Date Issued To Notice No.
Issued 80-41 Failure of Swing Check 11/10/80 All power reactor Valve in the Decay Heat facilities with an Operating Removal System at Davis-License (OL) or Construction Besse Unit No. 1 Permit (CP) 80-42 Effect of Radiation 11/24/80 All power reactor on Hydraulic Snubber Fluid facilities with an Operating License (0L) or Construction Permit (CP) 80-43 Failures of the Continuous 12/5/80 All power reactor Water Level Monitor for facilities with an the Scram Discharge Volume Operating License (OL) at Dresden Unit No. 2 or Construction Permit (CP) 80-44 Actuation of ECCS in the 12/16/80 All power reactor Recirculation Mode While facilities with an in Hot Shutdown Operating License (0L) or Construction Permit (CP) 80-45 Potential Failure of 12/17/80 All pressurized water BWR Backup Manual Scram reactor facilities with Capability an Operating License (0L)
Construction Permit (CP) 81-01 Possible Failures of 1/16/81 All power reactor facilities General Electric Type with an Operating License HFA Relays (0L) Construction Permit (CP) 81-02 Trant?ortation of 1/23/81 All Radiography licensees Radiography Devices 81-03 Checklist for Licensees 2/12/81 All power reactor Making Notifications of facilities with an Significant Events in Operating License (OL)
Accoraance with 10 CFR Part 50.72 Enclosure
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