ML19322C901
| ML19322C901 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/31/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Arnold R METROPOLITAN EDISON CO. |
| References | |
| IEIN-79-37, NUDOCS 8002050159 | |
| Download: ML19322C901 (1) | |
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UNITED STATES g
I NUCLEAR REGULATORY COMMISSION a
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REGION I 631 PARK AVENUE
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W xlNo or Pnuss:A. P1ENNSYt.VANIA 194o6 0:cket Nos. 50-289 DEC 311979 50-320 Metropolitan Edison Company ATTN:
Mr. R. C. Arnold, Sr.
Senior Vice President 100 Interpace Parkway Parsippany, New Jersey 07054 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 j
licensee actions may be requested or required.
If you have questions regarding this matter, please contact this office.
Sincerely, b
N' I y
- fBoyce H. Grierv 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:
J. G. Herbein, Vice President N: : lear Operatf ors E. G. Wallace, Licensing Manage' G. P. Miller, Manager, Unit 1 J. J. Colitz, Manager Plant Engineering (TMI-1)
J. J. Barton, Manager Site Operations
- 8. Elam, Manager Plant Engineering (TMI-2)
L. W. Harding, Supervisor of Licensing R. F. Wilson, Director TMI-2 I. R. Finfrock, Jr.
R. W. Conrad G. F. Trowbridge, Esquire J. B. Lieberman, Esquire M. Mary V. Southard, Chairperson, Citizens for a Safe Environment l
8002050 i
s.
ENCLOSURE 1 UNITED STATES ISINS NO.:
6870 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT 7910250525 WASHINGTON, D.C.
20555 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 possible violation of Part 10 CFR 50.55(e) and/or 10 CFR 21 Regulations concerning reportacility of recently discovered stress corrosion cracking in Westinghouse 1800 rpm low pressure turbine discs.
Westinghouse had made a presentation on the turbine disc crackir.g to electric utility executives on October 30, 1979.
Telephone discussions between the NRC staff and Westinghouse'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 (f.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's Zion Unit 1 LP turbino, ultrasonic examination revealed embedded cracks located on the inlet side on the disc bore area where no cracks had been previously l
observed.
Ultrasonic measurements indicate this disc bore cracking is of greater depth than tha 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 corrosion cracking observed in the keyways.
The probable cracking mechanism and impact on disc integrity is being further evaluated cy Westinghouse.
A seeting 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 p!snt inspection priorities.
In response to the staffs' 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, recem-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.
Encicsure 1 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 Corsolidated Edison's plans for prompt evaluation of this potential problem at this unit. lists the PWR plants having Westinghouse 1500/1800 rpm turbines.
The AA category represents those turbines which apoear to have the earliest need for inspection. With the exception of Yankee xowe, 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 l
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.
j 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 O
Attachmen+.1 to IE Information Notico Ns. 79-37 Page 1 of 3 CATEGORY AA UTILITY STATION UNIT Florida, P&L Turkey Point 3
Consolidated ED.
Indian Point 2
PASNY Indian Point 3
Arkansas P&L Russellville 1
VEPCO Surry 1
Carolina P&L Robinson 2
So. Calif. Ed.
San Onofre 1
Yankee A.P.
Rowe 1
Wisc. Mich. Pwr.
Point Beach 1
Consumers Pwr.
Palisades 1
Commonwealth Ed.
Zion 1 1
Commonwealth Ed.
Zion 2 2
Florida P&L Turkey Point 4
Nebraska PPO Cooper 1
Wisc. Mich. Pwr.
Point Beach 2
Maine Yankee Bailey Point 1
Rochester G&E Ginna 1
Northern States Prairie Island 1
Wisc. P.S.
Kewaunee 1
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. to IE Informatien N2tica N2. 79-37 Page 2 of 3 CATEGORY A UTILITY STATION UNIT Alabama Power Farley 1
Alabama Power Farley 2
Baltimore G&L Calvert Cliffs 2
Carolina P&L Harris 1
Carolina P&L Harris 2
Carolina P&L Harris 3
Carolina P&L Harris 4
Cincinnati G&E Iimmer 1
Commonwealth Ed.
Byron 1
Commonwealth Ed.
Byron 2
Commonwealth Ed.
Braidwood 1
Commonwealth Ed.
Braidwood 2
Connecticut Yankea Haddam Neck 1
Duke Power McGuire 1
Duke Power McGuire 2
Duquesne Lt.
Shippingport 1
Ouquesne Lt.
Beaver Valley 1
Ouquesne Lt.
Beaver Valley 2
Florida Power Corp.
Crystal River 3
Florida Power & Lt.
St. Lucie 1
Florida Power & Lt.
St. Lucie 2
Houston L&P So. Texas 1
Hauston L&P So. Texas 2
Louisiana P&L Waterford 3
Metropolitan Ed.
Three Mile Island 2
Northern States Pwr.
Prairie Island 2
Pub. Service E&G Salem 1
Pub. Service E&G Sales 2
Pacific G&E Diablo Canyon 1
Pacific G&E Ofablo Canyon 2
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~ to IE Informttion N3tice No. 79-37 Page 3 of 3 CATEGORY A UTILITY STATION UNIT P.S. Indiana Marble Hill 1
P.S. Indiana Marble Hill 2
Puget Sound P&L Skagit 1
SMUD.
Rancho Seco 1
TVA Sequoyah 1
TVA Sequoyah 2
TVA Watts Bar 1
TVA Watts Bar 2
VF?CO North Anna 1
VEPCO North Anna 2
VEPCO North Anna 3
VEPCO North Anna 4
VEPCO North Anna 2
WPPSS Hanford 2
WPPSS WNPS 1
WPPSS WNPS 3
WPPSS WNPS 4
WPPSS WNPS 5
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. to Information N5tica Ms. 79-37 UTILITY STATION UNIT Duke Power Co.
Oconee 1
Ouke 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 WPPSS Hanford 1
- b ENCLOSURE 2 IE Information Notice No. 79-37 Date:
December 31, 1979 Page 1 of 1 RECENTLY ISSUED IE INFORMATION NOTICES Information Subject Date Issued to Notice No.
Issued 79-12A Attempted Damage to New 11/9/79 All Fuel Facilities, Fuel Assemblies Research Reactors and Power Reactors with an Operating License (OL) or Construction Permit (CP) 79-27 Steam Generator Tube 11/16/79 All Power Reactor Faci-Ruptures at Two PWR lities with an OL or CP Facilities 79-28 Overloading of Structural 11/16/79 All Power Reactor Faci-Elements Due to Pipe Support lities with an OL or CP Loads 79-29 Loss of Nonsafety Related 11/19/79 All Power Reactor Faci-Reactor Coolant System In-lities with an OL or CP strumentation During Operation 79-30
.Seporting of Defects and 12/6/79 All Power Reactor Faci-Noncompliances, 10 CFR lities with an OL Part 21 or CP 79-31 Use of Incorrect Amolified 12/13/79 All Power Reactor Faci-Response Spectra (ARS) lities with an OL or CP 79-32 Separation of Electrical 12/21/79 All Power Reactor Faci-Cables for HPCI and ADS lities with an OL or CP 79-33 Improper Closure of Primary 12/21/79 All Power Reactor Faci-Containment Access Hatches lities with an OL or CP 79-34 Inadequate Design of Safety-12/31/79 All Power Reactor Faci-Related Heat Exchangers lities with an OL or CP 79-35 Control of Maintenance 12/31/79 All Power Reactor Faci-and Essential Equipment lities with an OL or CP 79-36 Computer Code Defect in 12/31/79 All Power Reactor Faci-Stress Analysi: af Piping lities with an OL or CP Elbow l
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