ML19350A677
| ML19350A677 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 02/27/1981 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Millen C PUBLIC SERVICE CO. OF COLORADO |
| References | |
| NUDOCS 8103160642 | |
| Download: ML19350A677 (1) | |
Text
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UNITED STATES pOR:HQ
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+i NUCLEAR REGULATORY COMMISSION LPOR g
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$11 RYAN PL.AZA ORIVE. SusTE 1%0 "9
v ARUNGToN. TEXAS 75011 State February 27,I92/
Occket No. 50-257 ch !, g/.g e
SnEl['[hlYh Public Service Comoany of Colorado E
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Mr. C. K. Millen 1
Senior Vice President S
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y Gentlemen:
13 This IE Information Notice is provided as an early notification of a ::ossibly significan; matter and it is expected :na recipients will review the infoma-mation for possible aaplicability to their facility. No res::ense is requested at nis time.
If furtner NRC evaluations so indicate, an IE Circular or Bulletin will be issued to further reco:nnend or request s::ecific licensee actions.
If you have cuestions regarding :nis matter, please c::ntact the Director of :ne appropriate NRC Regional Office.
Sincerely,
' '.7O
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.i-, w Karl 7. Seyfrit
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Director
Enclosures:
1.
IE Infomation Notice No. 31-04 2
2.
List of Recently Issued IE Information Notices
- 0. W. '4areccourg, Nuclear Procuction Manager For: St. Vrain Nuclear Station
?. O. Box 268
?'a:: evil'e, Calcraco 30551 L. 3 rey, Manager, Quait:y Assurance 810 s 1 e 06'/9 p
o SSINS No.: 6835 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 i
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 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 frem the T-fitting of the "A" main steam line for analysis.
Controlled excavation and depth l
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.
VEPC0 has planned an ultrasonic examination of similar welc'ments in Surry Unit 2 l
main steam lines utilizing " Hot Piping" ultrasonic techniques.
Preparations are also being made to ultrasonic examine similar weldments at North Anna Unit 1, l
currently in cold shutdown for refueling.
l Recommendation to Licensees:
i 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 l
plants.
For those plants having similar main steam line configurations wnicn are currently in a refueling or extended repair outage, it is recommended that a ultrasonic and/or radiographic examination of the three welds and counterbore areas of the T-fittings be performed before resumption of l
operations, unless some current basis for assurance of piping integrity is available.
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:
Sketch
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IE Information Notice No. 81-04 February 27, 1981 4
LISTING OF 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 (T 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 faciiities l
General Electric Type with an Operating License HFA Relays (0L) Construction Permit (CP) 81-02 Transportation of 1/23/81 All Radiography licensees Radiography Devices l
81-03 Checklist for Licensees 2/12/81 All power reactor Making Notifications of facilities with an Significant Events in Operating License (OL)
Accordance with 10 CFR Part 50.72 i
Enclosure k