ML19320A847
| ML19320A847 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 06/11/1980 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 8007020676 | |
| Download: ML19320A847 (5) | |
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UNITED STATES e
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WASHINGTON, D. C. 20555 j
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June 11, 1980 Docket No. 50-155 Mr. David P. Hoffman Nuclear 1.icensing Administrator Consumers Power Cogany 212 West Michigan Avenue Jackson, Michigan 49201
Dear Mr. Hoffman:
On December 28, 1979, the NRC Office of Inspection and Enforcement issued l
Information Notice No. 79.37 that discussed the discovery of cracks in the keyway and bore sections of discs in Westinghouse low-pressure turbines.
A copy of this Information Notice with an errata sheet is enclosed.
Subse-quently, all licensees / users of lew-pressure turbines manufactured by General Electric were invited to meet with the NRC staff and' representatives of the vendor on January 9,1980, to discuss the probability of disc cracking in these turbines. A summary of this meeting and the General Electric Cogany's presentation are also enclosed with this letter.
At the time of the January 9 meeting, General Electric did not have any recent results of ultrasonic inspections of its low-pressure turbines. Since that date, full UT inspections have been performed on six rotors at five nuclear power plants. Some indications in the keyway region have been reported in discs at three of these plants. General Electric personnel believe that these indications were caused by water erosion rather than by stress corrosion.
The staff desires to learn more about the underlying reasons for the indica-tions found and the probable rate of growth of these indications and their effects on turbine disc integrity.
For this purpose, we request that you provide the information sought in to this letter and address its safety significance. Under the i
provisions of in CFR j50.54(f) your retpen:e is requested within 30 days of
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the receipt of this letter. A copy of this letter is being telecopied to you, along with Enclosure 3.
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Mr. David P. Hoffman June 11, 1980 i
It is sy understanding that additional UT inspections are to be performed by General Electric in the near future. We encourage this action as being the only certain means of determining the integrity of turbine discs. We also recommend that if you have not already done so, you develop a schedule for performing a full UT inspection of at least one of your low pressure l
turbines during the next major outage of your Big Rock Point Nuclear Power Plant.
This request for generic information was approved by GA0 under clearance number B-180225 (S79014); this clearance expires June 30, 1980.
Si cerely.
p1 ennis M. Crutchfield, Ch Operating Reactors Granch #5 Division of Licensing
Enclosures:
1.
Information Bulletin No. 70.37 2.
Meeting Summary 3.
Information Requests cc: See next page i
i
f Mr. David P. Hoffman June 11, 1980 I
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cc:
Mr. Paul A. Perry, Secretary V. S. Environmental Protection Consumers Power Cogany Agency 212 West Michigan Avenue Federal Activities Branch Jackson, Michigan 49201 Region V Office
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ATTN: EIS COORDINATOR Judd L. Bacon, Esquire 230 South Dearborn Street Consumers Power Cogany Chicage, Illinois 60604 212 West Michigan Avenue Jackson, Michigan 49201 Herbert Grossman, Esq., Chairman Atomic Safety and Licensing Board Joseph Gallo, Esquire U. S. Nuclear Regulatory Comission Isham, Lincoln & Beale Washington, D. C.
20555 h
1120 Connecticut Avenue Room 325 Dr. Oscar H. Paris Washington, D. C.
20036 Atomic Safety and Licensing Board U. S. Nuclear Regulatory Comission Peter W. Steketee, Esquire Washington, D. C.
20555
'f 505 Peoples Building Grand Rapids, Michigan 49503 Mr. Frederick J. Shon Atomic Safety and Licensing Board Sheldon, Harmon and Weiss U. S. Nuclear Regulatory Commission 1725 I Street, N. W.
Washington, D. C.
20555 Suite 506 Washington, D. C.
20006 Big Rock Point Nuclear Power Plant 3
ATTN: Mr. C. J. Hartman Mr. John O'Neill, II Plant Superintendent Route 2, Box 44 Charlevoix, Michigan 49720 Maple City, Michigan 49664 Christa-Maria Charlevoix Public Library Route 2, Box 108C 107 Clinton Street Charlevoix, Michigan 49720 Charlevoix, Michigan William J. Scanlon, Esquire Chairman 2034 Pauline Boulevard County Board of Supervisors Ann Arbor, Michigan 48103 t
Charlevoix County Charlevoix, Michigan 49720 Office of the Governor (2)
Room 1 - Capitol Building Lansing, Michigan 48913 l
Director, Technical Assessment Division
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Office of Radiation Programs
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(AW-459)
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U. S. Environmental Protection Agency Crystal Mall #2 Arlington, Virginia 20460
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f REQUEST FOR_INFOR!%TIOff RELATED TO TURBINE DISCS _
SITE SPECIFIC GENERAL OVESTIO'IS - To Be Comoleted in 30 Days Provide the following information for each LP turbine:
I.
Turbine type A.
Number of hours of operation for each LP turbine at time of last B.
turbine inspection or if not inspected, postulated to turbine inspection C.
Number of turbine trips and overspeeds For each disc:
D.
type of material including material specifications 1.
tensile properties data 2.
toughness properties data including Fracture Appearance Transition 3.
Temperature and Charpy upper steel energy and temperature keyway temperatures 4.
critical crack size and basis for the calculation 5.
calculated bore and keyway stress at operating design overspeed 6.
7.
calculated K1c data 8.
minimum yield strength specified for each dise Provide details of the results of any completed inservice inspection of II.
LP turbine rotors, including areas examined, since issuance of an operating For each indication detected, provide details of the location license.
of the indication, its orientation, size, and postulated cause.
Provide the nominal water chemistry conditions for each LP turbine and III.
describe any condenser inleakages or other significant changes in water chemistry to this point in its operating life.
If your plant has not been inspected, describe your preposed schedule and IV.
approach to ensure that turbine cracking does not exist in your turbine.
If your plant has been inspected and plans to return or has returned to I
V.
power with cracks or other defects, provide your proposed schedule for the next turbine inspection and the basis for this inspection schedule, 4
i including postulated defect growth rate.
Indicate whether an analysis and evaluntion reqardinq turbino mf utic,
VI.
If auc an have been perfonned for your plant and provided to the staff.
analysis and evaluation has been performed and reported, please provide j
In the event appropriate references to the available documentation.
that such studies have not been made, consideration should be given to
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scheduling such an action, i
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, GI!:ERIC 00ESTIOils - To Se Comoleted in 30 Days Describe what quality control and inspection procedures are used for I.
the disc bore and keyway areas.
Provide details of the General Electric repair / replacement procedures II. ' for faulty discs.
What immediate and long term actions are being taken by General Electric III.
What to minimize future " water cutting" problems with turbine discs?
actions are being recommended to utilities to minimize " water cutting" of discs?
Describe fabrication and heat treatment sequence for discs, including IV.
thermal. exposure'during shrinking operations.
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