ML18081A897
| ML18081A897 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 12/28/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Schneider F Public Service Enterprise Group |
| References | |
| NUDOCS 8001140547 | |
| Download: ML18081A897 (8) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION REGION I 631 PARK AVENUE KING OF PRUSSIA, PENNSYLVANIA 19406 OEC 3 1 1979 Public Service Electric and Gas Company ATTN:
Mr. F. W. Schneider Vi~e President - Production 80 Park Place Newark, New Jersey 07101 Gentlemen:
This Information Notice is provided as an early notification of a possibly significant matter. It is expected that recipients will review the infor-mation for possible applicability to their facilities.
No specific action or response is requested at this time.
If NRC evaluations so indicate, further li'censee actions may be requested or required.
If you have questions regarding this matter, please contact this office.
Sincerely, tf/;fa1 a& ~
Director
Enclosures:
- 1.
IE Information Notice No. 79-37 with attachments
- 2.
List of Recently Issued IE Information Notices CONTACT:
L. E. Tripp (215-337-5282) cc w/encls:
F. P. Librizzi, General Manager - Electric Production E. N. Schwa l j e, Manager - Quality Assurance R. L. Mittl, General Manager - Licensing and Environment
- H. J. Midura, Manager - Salem Generating Station
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ENCLOSURE 1 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 ISINS NO.:
6870 Accession No.:
7910250525 IE Information Notice No. 79-37 Date:
December 31, 1979 Page 1 of 2 CRACKING 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 possibl~ violation of Part 10 CFR 50.55(e) and/or 10 CFR 21 Regulations 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 cracking to electric utility executives on October 30, 1979.
Telephone discussions between the NRC staff and Westinghouse 1 s Turbine Division on November 20, 1979 established that cracking, attributed to stress corrosion phenomena, had been* found in the keyway areas of several LP turbine discs at operating 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 also notified on November 20, 1979 that during the current overhaul of Commonwealth Edison 1 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 greater depth than the keyway cracks found to date.
According to Westinghouse, these bore cracks have been metallurgically examined and preliminary findings show them not to be typical of classical stress corros1on cracking observed in the keyways.
The probable cracking mechanism and impact on disc integrity is being further evaluated by Westinghouse.
A meeting 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 1 request, Westinghouse provided the staff an updated report on December 21, 1979 regarding the current field inspection program 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 Beach returned to power on December 23, 1979 with a*small crack in the No. 2 disc of LP Turbine No. 2.
An analysis by Westinghouse indicated that the observed crack will not attain critical dimensions during 28 additional months of turbine operation.
The NRC staff is evaluating the turbine inspection results and analysis by Westinghouse.
IE Information Notice No. 79-37 Date:
December 31, 1979 Page 2 of 2 Westinghouse also notified the staff that extrapolation of information obtained from Indian Point Unit 3 inspection and analysis indicates that disc cracking could be significant at Indian Point Unit 2 and the turbines should be inspected sooner than the spring outage of 1980.
The NRC staff is currently reviewing Consolidated Edison 1 s plans for prompt evaluation of this potential problem at this unit. lists the PWR plants having Westinghouse 1500/1800 ~pm turbines.
The AA category represents those turbines which appear to have the earliest need for inspection.
With the exception of Yankee Rowe, Westinghouse has recommended to utilities that inspection of these machines be completed by the Spring 1980 outage period.
The Rowe unit is uninspectable by the present ultrasonic techniques due to its design.
Westinghouse has recommended the remaining machines of the Category A plants be inspected as their service periods approach five years or in the event significant corrosion problems become evident during this time.
The NRC staff is currently reviewing the need for inspection of those PWR plants having other interfacing turbine designs shown in Attachment 2.
Changes to the forementioned inspection schedules proposed by Westinghouse may be necessary as new technical information becomes available.
From the information available to the NRC staff at this time it appears that cracking may be more generically widespread in turbine discs (e.g., keyways and bore areas) than previously observed.
It is important to note that the UT inspections performed by Westinghouse thus far were essentially limited to the keyways (disc outlet) of selected discs whereas the Zion Unit 1 inspection results indicate that examination of the disc bore section must be taken into account.
Also, Westinghouse is currently re-evaluating their previously estimated
- turbine missile energies based on recent missile test results from model symmetric and non-symmetric missile impact tests.
Their preliminary findings, although subject to change, now indicate possible higher missile exit energies in some cases than previously expected.
This Information Notice is provided as an early notification of a possibly significant matter, the allegations and the generic safety implications of which are currently undergoing review by the NRC staff. It is expected that recipients will review the information applicable to their facilities.
If NRC evaluations so indicate, further licensee actions may be requested or required.
Embedded cracking in keyways and disc bore areas have been observed only in Westinghouse LP turbines thus far.
However, the NRC staff believes that turbines of other manufacturers should be included in consideration of this problem.
No written response to this Information Notice is required.
If you have any questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Attachments:
As stated to IE Information Notice No. 79-37 UTILITY.
PASNY Arkansas P&L VEPCO Carolina P&L So. Calif. Ed.
Yankee A. P.
Wisc. Mich. Pwr.
Consumers Pwr.
Commonwealth Ed.
Commonwealth Ed.
Florida P&L Nebraska PPD Wisc. Mich.* Pwr.
Maine Yankee Rochester G&E Northern States Wisc. P.S.
. CATEGORY AA STATION Turkey Point Indian Point Indian Point Russellville Surry Robinson San Onofre Rowe Point Beach Palisades Zion 1 Zion 2 Turkey Point Cooper Point Beach Bailey Point Ginna Prairie Island Kewaunee Page 1 of 3 UNIT 3
2 3
1 1
2 1
1 1
1 1
2 4
1*
2 1
1 1
1
UTILITY Alabama Power Alabama Power Baltimore G&L Carolina P&L Carolina P&L Carolina P&L Carolina P&L Cincinnati G&E Commonwealth Ed.
Commonwealth Ed.
Commonwealth Ed.
Commonwealth Ed.
Connecticut Yankee Duke Power Duke Power Duquesne Lt.
Duquesne Lt.
Duquesne Lt.
Florida Power Corp.
Florida Power & Lt.
Florida Power & Lt.
Houston L&P Houston L&P Louisiana P&L Metropolitan Ed.
Northern States Pwr.
Puo. Service E&G Pub. Service E&G Pacific G&E
. Pacific G&E to IE Information Notice No. 79-37 CATEGORY A STATION Farley Farley Calvert Cliffs Harris Harris Harris Harris Zimmer Byron Byron Braidwood Braidwood Haddam Neck
.McGuire McGuire Shippingport Beaver Valley Beaver Valley Crystal River St. Lucie St. Lucie So. Texas So. Texas Waterford Three Mile 1sland Prairie Island Salem Salem Diablo Canyon Diablo Canyon Page 2.of 3 UNIT 1
2 2
1 2
3 4
1 1
- 2.
1 2
1 1
2 1
1 2
3 1
2 1
2 3
2 2
1 2
1 2
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e e to IE Information Notice No. 79-37 Page 3 of 3 CATEGORY A UTILITY STATION UNIT P.S. Indiana Marble Hill 1
P.S. Indiana Marble Hi 11 2
Puget Sound P&L Skagit 1
SMUO.
Rancho Seco 1
TVA Sequoyah
.1 TVA Sequoyah 2
TVA Watts Bar 1
TVA Watts Bar 2
VEPCO North Anna 1
VEPCO North Anna 2
VEPCO North Anna 3-VEPCO North Anna 4
VEPCO North Anna 2
WP PSS Hanford 2
WPP SS WNPS 1
WP PSS WNPS 3
WP PSS WNPS 4
WP PSS WNPS 5
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e e to Information Notice No. 79-37 UTILITY STATION UNIT Duke Power Co.
Oconee 1
Duke Power Co.
Oconee 2
Duke Power Co.
Oconee 3
OPPD Ft. Calhoun 1
Baltimore Electric Calvert Cliffs 1
& Gas Metropolitan Edison Three Mile Island 1
Indiana & Michigan D.C. Cook 1
Electric Indiana & Michigan D.C. Cook 2
Electric Northeast Utilities Millstone 2
Portland General Trojan 1
Electric Toledo Edison Davis Besse 1
Arkansas Power &
Arkansas Nuclear One 2
Light WP PSS Hanford 1
Information Notice No.79-12A 79-27 79-28 79-29 79-30 79-31 79-32 79-33 79-34 79-35 79-36 ENCLOSURE 2 IE Information Notice No. 79-37 Date:
December 31, 1979 Page l of 1 RECENTLY ISSUED IE INFORMATION NOTICES Subject Attempted Damage to New Fuel Assemblies Date Issued to Issued 11/9/79 All Fuel Facilities, Research Reactors and Power Reactors with an Operating License (OL) or Construction Permit (CP)
Steam Generator Tube 11/16/79 All Power Reactor Faci-Ruptures at Two PWR lities with an OL or CP Facilities Overloading of Structural 11/16/79 All Power Reactor Faci-Elements Due to Pipe Support lities with an OL or CP Loads Loss of Nonsafety Related 11/19/79 All Power Reactor Faci-Reactor Coolant System In-lities with an OL or CP strumentation During Operation Reporting of Defects and Noncomplianc~s, 10 CFR Part 21 12/6/79 All Power Reactor Faci-lities with an OL or CP Use of Incorrect Amplified 12/13/79 All Power Reactor Faci-Response Spectra (ARS) lities with an OL or CP Separation of Electrical 12/21/79 All Power Reactor Faci-tables for HPCI and ADS lities with an OL or CP Improper Closure of Primary 12/21/79 All Power Reactor Faci-Containment Access Hatches lities with an OL or CP Inadequate Design of Safety-12/31/79 All Power Reactor Faci-Related Heat Exchangers lities with an OL or CP Control of Maintenance and Essential Equipment Computer Code Defect in Stress Analysis of Piping
.Elbow 12/31/79 All Power Reactor Faci-lities with an OL or CP 12/31/79 All Power Reactor Faci-1 ities with an OL or CP