ML19290E712
| ML19290E712 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 02/25/1980 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | Burstein S WISCONSIN ELECTRIC POWER CO. |
| References | |
| NUDOCS 8003140431 | |
| Download: ML19290E712 (3) | |
Text
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[pn nua (o UNITED STATES
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,v.c(g; NUCLEAR REGULATORY COMMISSION C
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February 25, 1980 Docket No.
50-301 Mr. Sol Burstein Executive Vice President Wisconsin Electric Pcwer Company 231 West Michigan Street Milwaukee, Wisconsin 53201
Dear Mr. Burstein:
On December 28, 1979 the NRC Office of Inspection and Enforcement issued Inf ormation Notice No. 79-37 that presented information available to the staff related to the discovery of cracks in the keyway and bore sections of Westinghouse 1800 rpm low pressure turbines. A copy of this Information Notice with errata sheet is enclosed.
Westinghouse notified utility users of this potential problem on October 30, 1979 and was requested by the staff to present a similar briefing in Bethesda, Maryland on December 17, 1979. You were contacted on December 14, 1979 and invited to send representatives to the staff briefing and also were requested to advise the staff of the actions being taken in regard to this potential problem at your operating nuclear power plant.
Westinghouse was later requested to meet again with the staff and licensee-users on January 8,1980 to supplement the information provided in the earlier meeting and in interim correspondence with the staff.
On the basis of information provided by Westinghouse and recent indications from turbine disc inspections now underway at Arkansas Nuclear One Unit 1, Beaver Valley Unit i and Indian Point Unit 2, it is evident that the probability of crack formation in these turbine discs is significantly greater than previously assumed by the vendor.
In light of this information and the actions being taken by the licensee-users, we consider this warrants your prompt full UT inspection of LP rotor discs, especially the keyways and bore areas, and documentation to the NRC of your justification for continued operation until such inspections are made and all defects thus identified are corrected.
Therefore, in accordance with 10 CFR 50.54(f), you are requested to provide within 20 days of the date of this letter, or in any event prior to restart if your unit is not operating, written statements, signed under oath or affirmation, which will enable the staff to determine whether or not your license to operate Point Beach, Unit No. 2 should be modified, suspended, or revoked.
As part of your statement, you should provide and address the safety significance of the information requested in Enclosure 2 to this letter.
6003140
Mr. Sol Burstein February 25, 1980 Because of the general nature of the information sought in Enclosure 2 we are transmitting a copy of this enclosure to Westinghouse by separate letter. As discussed in the December 17, 1979 meeting we urge you to address the generic aspects of this problem and to coordinate your responses through an owner's group.
Sincerely,
/
Darrell G. ~ sen ut, Acting Director Division o Operating Reactors
Enclosures:
1.
IE Information Notice No. 79-37 With Errata Sheet 2.
Request for Information Related to Turbine Disc Cracks - 20 Day Response cc: w/ enclosures See next page
Mr. 501 Eurstein Wisconsin Electric Power Company February 25, 1980 cc:
P.r. Bruce Churchill, Esquire Shaw, Oittman, Potts and Trowbri:ge 13C0 M Street, N.W.
kasningtt1, D. C.
20036 Document Department University of Wisconsin Stevens Point Library Stevens Point, Wisconsin 54481 Pr. Glenn A. Reed, Manager Nuclear C?erations Wisconsir. Electric Power Company Point Beach Nuclear Plant 6510 Nuclear Road Two Rivers, Wisconsin 54241
Emi are i UNITED STALES.
ISINS NO.:
6870 NUCI FAR REGUU$10RY COMMISSION Accession No.:
OflICE OF INSPECTION AND ENFORCEMENT 7910250525 tlASHINGTON, D.C.
20555 Dec ec.be r 28, 1979 IE Infornation Notice No. 79-37 CT.ACKING IN LOW PRESSURE TURBINE DISCS Decription 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 1300 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 Nov w.bcr 20, 1979 established that cracking, attributed to stress corrosion Aen.
na, had been fcund in the keyway areas of several LP turbine discs at operating plaats and that inservice inspection techniques (i.e., in situ ultra-sonic c m.instioa) for crack detection have been developed and are being imple-c.?nted in the field.
The Office of Inspoction and Enforcecant was also notified on N: e.ber 20, 19/9 that during the current overhaul of Co nor.sealth Edison's Zion Unit 1 LP turbine, ultrasonic exa,..ination revealed embedded cracks located on the inlet sida un the disc bore area whcre no cracks had been previcusly cbscr.ed. Ultr m nic measurements indicate this disc bore cracking is of greater depth than the kepay cracks found to date.
Acco: ding to Westinghcuse, these bore crocks have been metallurgically examined and preliminary findings show them not to be typical of classical stress corrosion cracking observed in the keyways.
The proWble cracking mechanism and impact on disc integrity is being further evaluated by 'elastinghcuse.
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 nissile evaluation, inspection techniques and plant inspection priorities.
In response to the staf fs' request, Westinghouse provided the staff an updated report on December 21, 1979 regarding the current field inspection program that included a list f 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 Sorry 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 pcwer.
Point wer on December 23, 1979 with a small crack in the No. 2 di Westinghouse indicated that the ob DUPLICATE DOCUMENT during 28 additional conths of tur the turbine inspection results and Entire document previously entered into system under:
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