ML16340B491
| ML16340B491 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 02/27/1981 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Crane P PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 8103160661 | |
| Download: ML16340B491 (10) | |
Text
gP,A REGS~
Wp0
>>>>*<<+
UNITED STATES NUCLEAR REGULATORY COMMISSION REGION V 1990 N. CALIFORNIABOULEVARD SUITE 202, WALNUTCREEK PLAZA WALNUTCREEK, CALIFORNIA94596 February 27, 1981 Docket Nos. 50-275, 50-323 Pacific Gas and Electric Company P. 0.
Box 7442 San Francisco, California 94106
'ttention:
Mr. Philip A. Crane, Jr.
Assistant General Counsel
~IO'lI M,a+~~IgI0nPi C5 Gentlemen:
This information notice is provided as an early notification of a possibly significant matter and it is expected that recipients will review the information for possible applicability to their facilities.
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 the appropriate NRC Regional Office.
Sincerely, R.
H. Engelken Director
Enclosure:
1.
IE Information Notice No. 81-04 cc w/
enclosure:
M.
- Raymond, PGSE R. C. Thornberry, Plant Manager (Diablo Canyon)
E.
B. Langley, Jr.,
PGSE arO3~60
n/ r
<P,cX V>
SSINS No.: 6835 Accession No.:
8011040265 IN 81-04 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICF.
OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 February 27,1981 IE Information Notice No. 81-04:
CRACKING IN t1AIH STEAM LINES Descri tion of Circumstances:
The Virginia Electric Power Company promptly notified the HRC.on February 23, 1981 that a radiography examination, during the ongoing steam aenerator replacement outage at Surry Unit 1, had revealed a lenothy 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 ~onnection 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 120F around the fitting counterbore between the 4 o'lock,,to 8 o'lock 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-fi.tting 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 weldments jn Surry Unit 2 main steam lines utilizing "Kot Piping" ultrasonic techniques.
.Preparations are also being made to ultrasonic examine similar weldments at Horth Anna Unit 1, currently in cold shutdown for refueling.
Recommendation to Licensees:
This information is provided as an early notification of q significant safety matter that is still under review by the NRC staff. It is expected that recipients will review the information for possible applicabi]ity to their plants.
For those plants having similar main steam line configurations which are currently in a refueling or extended repair outage, itis recommended that a ultrasonic and/or radiographic examination of the three welds and counterbore areas of the T-fittings be performed before resumption of 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.
Attachments:
1.
Sketch 2.
Recently issued IE Information Notices
0 r,
i'C' Q
'i
$<v~
pg~MW'~ww > /
rv'<5'S:
(~~
J M~~~ dr~~
rc
$<y'WW~wMF~~
(Py+eaAPJ) 0
~/8t.
444 Wr~r~+
&Q zoW< ~
r-'
/6 if
/
4, iI i
1 v i a
f, I
\\
j
+l ',
1
RECENTLY ISSUED IE INFORMATION NOTICES Attachment 2
IN 81-04 Information Notice No.
81-03 81-02 81-01 80-45 80-44 Sub 'ect Checklist for Licensees Making Notifications of Significant Events in Accordance with 10 CFR 50.72 Transportation of Radiography Devices Poss ible Failures of General Electric Type HFA Relays Potential Failure of BWR Backup Manual Scram Capability Actuation of ECCS in the Recirculation Mode While in Hot Shutdown Date of Issue 2/12/81 1/23/81 1/16/81 12/17/80 12/16/80 Issued to All power reactor facilities.wi.th an OL A'}1 Radiography licensees All power reactor facilities with an OL or GP.
gl PH( fagi1ities with an.Ol. or CP Pll Pl<R facilities with an OL or CP 80-43 Failures of the Continuous 12/5/80, Water Level Monitor for the Scram Discharge Volume at Dresden Unit No.
2 All.power reactor faci.]i.ties with an OL or Cp 80-42 80-41 80-40 Effect of Radiation on Hydraulic Snubber Fluid Failure of Swing Check Valve in the Decay Heat Removal System at Davis-Besse Unit No.
1 Excessive Nitrogen Supply Pressure Actuates Safety-Relief Valve Operation to Cause Reactor Depressur-ization 11/24/80 11/10/80.
ll/10/80 All power reactor facilities with an OL or CP All power reactor facilities with an OL qr CP A]1 power reactor faciliti.es with an OL or CP OL = Operating Licenses CP = Construction Permits
pa
'P t