ML19246B164
| ML19246B164 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 06/25/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Groce R VERMONT YANKEE NUCLEAR POWER CORP. |
| References | |
| NUDOCS 7907120584 | |
| Download: ML19246B164 (1) | |
Text
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- ;.t>* * * %g 33 UNITED STATES 8 \\^
NUCLEAR REGULATORY COMMISSION
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,0 KING OF PRUSSIA, PENNSYLVANIA 19406 June 25, 1979 Docket No. 50-271 Vermont Yankee Nuclear Power Corpcration ATTN:
Mr. Robert H. Groce Licensing Engineer 20 Turnpike Road Westborough, Massachusetts 01581 Gentlemen:
The enclosed Bulletin 79-13 is forwarded to you for information. No written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely, Y-bit-(B ce H. Grier 1 rector
Enclosures:
1.
IE Bulletin No. 79-13 w/ Attachments 2.
List of IE Bulletinis Issued in Last 12 Months cc w/encls:
W. F. Conway, Plant Superintendent Ms. J. Abtv., Technical Secretary A. Z. Roisman, Natural Resources Defense Council 3
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342 26b 2 00 r12 o581
ENCLOSURE 1 UflITED STATES flUCLEAR REGULATORY C0f!!!ISSI0f!
0FFICE OF INSPECTION A!!D E!! FORCE!!ENT WASHINGTON, D.C.
20555 IE Bulletin No. 79-13 Date: June 25, 1979 Page 1 of 4 CRACKING IN FEEDUATER SYSTEM PIPIflG Description of Circumstances:
On fiay 20, 1979, Indiana and flichigan Power Company notified the NRC of cracking in two feedwater lines at' their D. C. Cook Unit 2 facility. The cracking was discovered fol hwing a shutdown on fiay 19 to investigate leakage inside containment.
Leaking circumferential cracks were identified m the 16-inch feedwater ePows adjacent to two steam generator nozzle elbow welds.
Subsequent radiographic examination revealed crack indications in all eight steam generator feedwater lines at this location on both Units 1 and 2.
On flay 25, 1979, a letter was sent to all PUR licensees by the Office of Nuclear Reactor Regulation which informed licensees of the D. C. Cook failures and requested specific information on feedwater system design, fabrication, inspection and operating histories. To further explore the ceneric nature of the cracking problem, the Office of Inspection and Enforcement reouested licensees of PWR olants in current outages to immediately conduct volumetric examination of certain feedwater piping welds.
As a result of these actions, several other licensees with !festinghouse steam generators reported crack indications.
Southern California Edison reported on June 5,1979, that radiographic examination revealed indicatfor s of cracking in feedwater nozzle-to-piping welds on two of three steam generators of San Onofre Unit 1.
On June 15, 1979, Carolina Power and Licht reported that radiography showed crack indications in similar locations at their H. B. Robinson Unit 2.
Duquesne Power and Light confirmed on June 18, 1979, that radiography has shown cracking in their Beaver Valley Unit 1 feedwater piping to vessel nozzle weld.
Public Service Electric and Gas Company reported on June 20, 1979 that Salen Unit 1 also has crack indications. !lisconsin Public Service company decided on June 20, 1979 to cut out a feedwater nozzle-to-pipe weld which contained questionable indication, for metallurgical examination.
As of June 22,1979 and since May 15, 1979 seven other PUP. facilities have inspected the feedwater nozzle-to-pipe welds without finding cracking indications.
The feedwater nozzle-to-pipe configurations _ fot 0.C.. Cook antLfor3an nnnf a
shown on the attached figures 1 and 2.
weld joint detail showing the principal DUPLICATE DOCUMENT d
are shown on the attached figure 3.
1 Entirt. document previously entered l
On March 17, 1977, during heat-up for hc into system under:
Unit 1, a leak was discovered in the ved the16-inchdiameterfeedwaterpipingtk OhMW ANO nondestructive examination of all nozzld No. of pages:
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342 267 l:
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