ML19224D562
| ML19224D562 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| 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 7907120617 | |
| Download: ML19224D562 (1) | |
Text
C
- ""%s TE f
c UNITED STATES E
NUCLE AR REGULATORY COMMISSION E,,.jk,,;f h Ij lb REGION V
. - O, ' h. '56.{ L / J 1990 N CAllFORNI A flOULEVARD
t,,
8 SUIT E 202. WA LNUT CR E E K PLAZA 4+*,*
WALNUT CR E E K, CALIFORNI A 94596 June 25,1979 Docket flo. 50-133 Pacific Gas and Electric Company 77 Beale Street San Francisco, California 54106 Attention: f4r. Philip A. Crane, Jr.
As3istant General Counsel Gentl emen:
The enclosed IE Bulletin No. 79-13 is forwarded to you for information.
lic written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely, ll [ G.-., 1 $..
R. H. Engelken Director
Enclosures:
1.
IE Bulletin fio. 79-13 2.
Listing of IE Bulletins Issued in Last 12 idonths cc w/enclor. ires:
W. Barr, P;&E W. A. Raymond, PG&E E. Weeks, PG&E, Humboldt Bay (L
4/4 mm o si, gg L
UtilTED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND EllFORCEMENT WASHINGTON, D.C.
20555 June 25, 1979 IE Bulletin No. 79-13 CRACKliiG IN FEEDWATER SYSTEM PIDING Description of Circumstances:
On May 20, 1979, Indiana and Mic:iigan Power Conpany notified the flRC 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 containnent.
Leaking circunferential cracks were identified in the 16-inch feedwater elbows adjecent to two stsm generator nozzle elbow welds.
Subsequent radiographic exanination revealed crack indications in all eight steam generator feedwater 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 infomed licensees of the D. C. Cook failures cnd requested specific infornation on feedwater systen design, fabrication, inspection and operating histories. To further explore the ceneric nature of the cracking problen, the Office of Inspection and Enforcerent requested licensees of PWR plants in current outajes to immediately conduct volurretric examination of certain feedwater piping welds.
As a result of these actions, several other licensees with kestinghouse steam generators reported crack indications.
Southern California Edison reported on June 5,1979, that radiographic examination revealed indicaties of cracking in feedv;ater nozzle-to-piping welds on two of three steam generators of San Onof e Unit 1.
On June 15, 1979, Carolina Power and Light reported that radiography sMwed crack ;ndications in similar locations at their H. B. Robinson
' tit 2.
Duque ne Power ar d Light confirned on June 18, 1979, that radiography has shown cracking in their Beaver Valley Unit 1 feeuwater piping to vessel nozzle weld.
Public Service Electric and Gas Company reported on Juna 20, 1979 that Salen Unit 1 also has crack indications. Wisconsin Public Servira company decided m June 20, 1979 to cut out a feedwater nozzle-to-pipe w.
which contained questionable indication, for metallo;ical examination. As of June 22, 1979 and since May 25, 1 2 9 ceven other PWR facilities have inspected the feedwater nozzle-to-pipe welds withoui. finding cracking indications.
The feedwater nozzle-to-pipe canfigurations for D.C. Cook and for San Onofre are shown on the attached figuro 1 and 2.
A typical feedwater pipe-to-nozzle weld joint detail showing the principal crack.iocations for D.C. Cook and San Onofre are shown on the attached figure 3.
[
( 3DUPLICAT - _oguggy7 D
) Entire e On March 17, 1977, during hect-up for F Unit 1, a leak was discovered 1.
- he vc l J t he 16-inch uiameter feedwater piping pinto system t previous 1 nondestructive examination of all nozz f
under.
Y entered 7
~Y (A~K 03n, J
ANO a
414 083 I
' vase l
~- %
- '~,