ML19224D610
| ML19224D610 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 06/25/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Wachter L NORTHERN STATES POWER CO. |
| References | |
| NUDOCS 7907130138 | |
| Download: ML19224D610 (1) | |
Text
TIC j#""G0(4 UNITED STATES f.
NUCLEAR REGULATORY COMMISSION e
e *., l REGION 111 t
799 ROOSE V E LT RO AD b 't...#
June 25, 1979
%,,,,4 G LE N E LLY N, ILLINOIS 60137 Docket No. 50-282 Docket No. 50-306 Northern States Power Company ATTN:
Mr. Leo Wachter Vice President Power Production and System Operation 414 Nicollet Mall Minneapolis, MN 55401 Gentlemen:
Enclosed is IE Bulletin No. 79-13 which requires action by you wi;h regard to your power reactor facility with an operating license.
Should you have any questions regarding this Bulletin or the actions required by you, please contact this office.
Sincerely, 7
James G. Keppler /
Director
Enclosures:
- 2. List of IE Bulletins Issued in Last 12 Months cc w/encls:
Mr.
F. P. Tierney, Jr.,
Plant Manager Central Files Director, NRR/ DPM Director, NRR/ DOR PDR Local PDR NSIC TIC John W.
Ferman, Ph.D.
Nuclear Engineer 367 046
[. - *
[ l _.-
7907130\\Y (
U.S. NUCLEAR REGULATonY COMMISSION OFFICE OF INSPECTTON AND ENFORCEAENT REGION IT.I June 25, 1979 IE rulletin No. 79-13 a
CRACKING IN FEEDWATER SYSTEM PIPING Description of Circumstances:
On May 20, 1979, Indiana and Michigan Power Company 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 containment. Leaking circunferential cracks were identified in the 16-inch feedwater elbows adjacent to two steam generator nozzle elbow velds.
Subsequent radiographic examination revealed crack indications in all eight steam generator feedwater lines at this location en 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 informed licensees of the D. C. Cook failures and regtested specific information en feedwater system design, fabrication, inspection and operating histories. To further explore the generic nature of the 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 Light reported that radiography showed crack indicatione 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 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 metallurgical 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 showing the principal crack locations for D.C. Cook and San Onofre are shown on the attached figure 3.
On March 17, 1977, during heat-up for hot f 7'~
"""~" "~' ' ~ ~ ' ' -
Unit 1, a leak was discovered in the vessel 6
DUPLICATE DOCUMENT the 16-inch diameter feedwater piping to st I
Entire document previously entered nondestructive examination of all nozzle we r,
into system under:
790GP 503 4S ANO 1
W 047 l
No. or pages:
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