ML19224D564
| ML19224D564 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 06/25/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Crane P PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7907120621 | |
| Download: ML19224D564 (1) | |
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UNITED STATES
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1930 N. C ALIFORNI A BOULEVARD
,y SUIT E 702, WALNUT CR E E K PL AZ A WALNUT CRE EK, CAllFORNi A 94596 June 25,1979 Docket flos. 50-275 50-323 Pacific Gas and Electric Company 77 Beale Street San Francisco, California 94106 Attention:
fir. Philip A. Crane, Jr.
Assistant General Counsel Gentlemen:
The enclosed IE Bulletin t;o. 79-13 is forwarded to you for information.
fio written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely, l/ t f 3
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R. H. Engelken Director
Enclosures:
1.
IE Bulletin flo. 79-13 2.
Listing of IE Bulletins Issued in Last 12 f4onths cc w/ enclosures:
R. Ramsay, Diablo Canyon, PG&E W. A. Raymond, PG&E J. D. Worthington, PGSE (W
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UNITED STATES NUCLEAR REGULATORY COT 11SSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 June 25, 1979 IE Bulletin No. 79-13 CRACKING IN FEEDWATER SYSTEM PIPING Description of Circumstances:
On May 20, 1979, Indiana and Michigan Power Conpany notified the NRC of cracking in two feedwater lines at their D. C. Cook Unit 2 facility. The cracking was discovered following a shutdown on May 19 to investigate leakage inside containrent.
Leaking circunferential cracks were identified in the 16-inch feedwater elbows adjacent to two steam generator nozzle elbow welds.
Subsequent radiographic examination revealed crack indications in all eight steam generator feeduater lines at this location on both Units 1 and 2.
On May 25, 1979, a letter was sent to all PWR licensees by the Office of Nuclear Reactor Regulation which infort:ed licensees of the D. C. Cook failures and requested specific information on feedwater system design, fabrication, inspection and operating histories. To further explore the generic nature of che cracking problem, the Office of Inspection and Enforcement requested licensees of PWR plants in current outages to immediately conduct volumetric examination of certain feedwater piping welds.
As a result of these actions, several other licensees with Westinghouse steam generators reported crack indications. Southern California Edison reported on June 5, 1979, that radiographic examination revealed indications 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 confirned 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 Salem Unit 1 also has crack indications. Wisconsin Public Service company decided on June 20, 1979 to cut out a feedwater nozzle-to-pipe weld which contained questionable indication, for netallurgical examination. As of June 22, 1979 and since May 25, 1979 seven other PWR facilities have inspected the feedwater nozzle-to-pipe welds without finding cracking indications.
The feedwater nozzle-to-pipe configurations for D.C. Cook and for San Onofre are shown on the attached figures 1 and 2.
A typical feedwater pipe-to-nozzle weld joint detail shouing the principal crack locations for D C.,CnoLM W n-are shown on the attached figure ~ ~
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4 DUPLICATE DOCUMENT On March 17, 1977, during heat-up Entire document previously entered Unit 1, a leak was discovered in the 16-inch diameter feedwater pi jinto system under:
nondestructive examination of all )
ggg3yf No. of pages:
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