ML14170A570
| ML14170A570 | |
| Person / Time | |
|---|---|
| Site: | Harris, Brunswick, Robinson  |
| Issue date: | 12/28/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Jackie Jones CAROLINA POWER & LIGHT CO. |
| References | |
| NUDOCS 8001250044 | |
| Download: ML14170A570 (9) | |
Text
NRl REfeo UNITED STATES NUCLEAR REGULATORY COMMISSION REGION il 101 MARIETTA ST., N.W., SUITE 3100 ATLANTA, GEORGIA 30303 In Reply Refer To:
~1?
~~ur 50-26 50Q2, 50-403 G JL T i Carolina Power and Light Company ATTN:
J. A. Jones Senior Executive Vice President and Chief Operating Officer 411 Fayetteville Street Raleigh, North Carolina 27602 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, James P. O'Reill Director
Enclosures:
- 1.
IE Information Notice No. 79-37
- 2.
List of Recently Issued IE Information Notices
DEC 28 1979 Carolina Power and Light Company
-2 cc w/encl:
A. C. Tollison, Jr.
Plant Manager Box 458 Southport, North Carolina 28461 R. Parsons, Site Manager Post Office Box 101 New Hill, North Carolina 27562 R. B. Starkey, Jr., Plant Manager Post Office Box 790 Hartsville, South Carolina 29550 5'**
UNITED STATES ISINS NO.:
6870 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT 7910250525 WASHINGTON, D.C. 20555 December 28, 1979 IE Information Notice No. 79-37 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 50.55e 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'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'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 corrosion 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' 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 December 28, 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'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 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 Enclosure 2. Changes to the forementioned inspection schedules proposed by Westinghouse may be necessary as new technical information becoies 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.
Enclosures:
As stated 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 PPD 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
(Continued)
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 Zimmer 1
Commonwealth Ed.
Byron 1
Commonwealth Ed.
Byron 2
Commonwealth Ed.
Braidwood 1
Commonwealth Ed.
Braidwood 2
Connecticut Yankee Haddam Neck 1
Duke Power McGuire 1
Duke Power McGuire 2
Duquesne Lt.
Shippingport 1
Duquesne Lt.
Beaver Valley 1
Duquesne Lt.
Beaver Valley 2
Flordia Power Corp.
Crystal River 3
Flordia Power & Lt.
St. Lucie 1
Flordia Power & Lt.
St. Lucie 2
Houston L&P So. Texas 1
Houston 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 Salem 2
Pacific G&E Diablo Canyon 1
Pacific G&E Diablo Canyon 2
(Continued)
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
VEPCO 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
UTILITY STATION UNIT Duke Power Co.
Oconee 1
Duke Power Co.
Oconee 2
Duke Power Co.
Oconee 3
OPPD Ft. Calhoun 1
Baltimore Electric
& Gas Calvert Cliffs 1
Metropolitan Edison Three Mile Island 1
Indiana & Michigan Electric D.C. Cook 1
Indiana & Michigan Electric D.C. Cook 2
Northeast Utilities Millstone 2
Portland General Electric Trojan 1
Toledo Edison Davis Besse 1
Arkansas Power &
Light Arkansas Nuclear One 2
WPPSS Hanford 1
IE Information Notice No. 79-37 Enclosure December 28, 1979 RECENTLY ISSUED IE INFORMATION NOTICES Information Date Notice No.
Subject Issued Issued To 79-37 Cracking in Low Pressure 12/28/79 All holders of power reactors Turbine Discs OLs and CPs 79-36 Computer Code Defect In 12/31/79 All holders of power reactor Stress Analysis of Piping OLs and CPs Elbow 79-35 Control of Maintenance and 12/31/79 All holders of power reactor Essential Equipment OLs and CPs.
79-34 Inadequate Design of Safety-12/27/79 All holders of power reactor Related Heat Exchangers OLs and CPs 79-33 Improper Closure of Primary 12/21/79 All holders of power reactor Containment Equipment Access OLs and CPs Hatches 79-32 Separation of Electrical 12/21/79 All power reactor facilities Cables for HPCI and ADS holding OLs and CPs 79-31 Use of Incorrect Amplified 12/13/79 All power reactor facilities Response Spectra (ARS) holding OLs and CPs 79-30 Reporting of Defects and 12/6/79 All power reactor facilities Noncompliances, 10 CFR holding OLs and CPs and Part 21 vendors inspected by LCVIP 79-29 Loss of NonSafety-Related 11/16/79 All power reactor facilities Reactor Coolant System holding OLs or CPs Instrumentation During Operation 79-28 Overloading of Structural 11/16/79 All power reactor facilities Elements Due to Pipe Support with an OL or CP Loads 79-27 Steam Generator Tube 11/16/79 All power reactor facilities Ruptures At Two PWR holding OLs and CPs Facilities79-12A Attempted Damage To New 11/9/79 All Fuel Facilities, Fuel Assemblies research reactors, and power reactors with an OL or CP