ML19211C118
| ML19211C118 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 12/28/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Goodwin C PORTLAND GENERAL ELECTRIC CO. |
| References | |
| NUDOCS 8001100098 | |
| Download: ML19211C118 (1) | |
Text
pa arcoq'o UNITED STATES 4
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.e WALNUT CREEK, CALIFORNI A 94596 December 28, 1979 Docket No. 50-344 Portland General Electric Company 121 S. W. Salmon Street Portland, Oregon 97204 Attention: Mr. Charles Goodwin, Jr.
Assistant Vice President Gentlemen:
This Information Notice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the information for possible applicability to their facilities. No specific action or response is requested at this time.
If NRC evaluations so indicate, further licensee actions may be requested or required.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely,
~
R. H. Engelken Director
Enclosures:
1.
IE Information Notice No. 79-37 2.
List of Recently Issued IE Information Notices cc w/ enclosures:
C. P. Yundt, PGE F. C. Gaidos, PGE l73b 9b3 L
y 001100 Of#
~
UNITED STATES ISINS NO.: 6870 NUCLEAR REGULATORY COMMISSION Accession No.:
0FFICE OF INSPECTION AND ENFORCEMENT 7910250525 WASHINGTON, D.C.
20555 December 28, 1979 IE Information Notice No. 79-37 CRACKIflG IN LOW PRESSURE TURBINE DISCS Description of Circumstances:
An anonymous letter was received by the Director of the Office of Inspection and Enforcement, on November 17, 1979 which alleged possible violation of Part 10 CFR 50.55e and/or 10 CFR 21 Reaulations concerning reportability of recently discovered stress corrosion cracking in Westinghouse 1800 rpm low pressure turbine discs.
~
Westinghouse had made a presentation on the turbine disc crackina to electric utility executives on October 30, 1979.
Telephone discussions between the NRC staff and Westinahouse's Turbine Division on November 20, 1979 established that crackina, attributed to stress corrosion ohenomena, had been found in the keyway areas of several LP turbine discs at operatina plants and that inservice inspection techniques (i.e., in situ ultra-sonic examination) for crack detection have been developed and are being imple-mented in the field. The Office of Inspection and Enforcement was al notified on November 20, 1979 that during the current overhaul of Commonwealth Edison's Zion Unit 1 LP turbine, ultrasonic examination revealed embedded cracks located on the inlet side on the disc bore area where no cracks had been previously observed. Ultrasonic measurements indicate this disc bore cracking is of creater depth than the keyway cracks found to date.
Accordina to Westinghouse, these bore cracks have been metallurgically examined and preliminary findinas show them not to be typica' of classical stress corrosion cracking observed in the keyways.
The probable cracking mechanism and impact on disc integrity is being further evaluated by Westinghouse.
A meetino was held on December 17, 1979 between the NRC staff, Westinghouse and utility representatives to discuss the disc cracking problem, repair alter-natives, turbine missile evaluation, inspection techniques and plant inspection priorities.
In response to the staffs' request, Westinghouse provided the staff an updated report on December 21, 1979 reaardina the current field inspection orocram that included a list of nuclear power plants already inspected, recom-mended inspection schedules and pertinent information related to LP turbines where cracks have been observed.
Inspections to date have identified turbine disc cracks at Surry Unit 2, Point Beach Unit 2, Palisades, Indian Point Unit 3 and Zion Unit 1.
All units except Point Beach Unit 2 will make repairs before the plants return to power. Point Be ember 23, 1979 with a small crack in the No. 2 disc Westinghouse indicated that the obser durina 28 additional months of turbin DUPLICATE DOCUMENT the turbine inspection results and an Entire document previously entered into system under:}h 2h9 No. of pages: ] .}}