ML19290E754
| ML19290E754 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 02/25/1980 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | Dunn C DUQUESNE LIGHT CO. |
| References | |
| TAC-12598, NUDOCS 8003140479 | |
| Download: ML19290E754 (3) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION
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February 25, 1980 Docket No.
50-334 Mr. C. N. Dunn, Vice President Operations Division Duquesne Light Company 435 Sixth Avenue Pittsburgh, Pennsylvania 15219
Dear Mr. Dunn:
On December 28, 1979 the NRC Office of Inspection and Pforcement issued Information Notice No. 79-37 that presented informativa 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 staf f 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 correspandence 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 1 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 Beaver Valley Power Station, Unit No.1 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.
8003140
Mr. C. N. Dunn 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,
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i's e u, Acting Director m
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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. C. N. Dunn Duquesne Light Cocpany Februa ry 25, 1980 cc: Gerald Charnoff, Esquire Mr. Jaces A. Werling Jay E. Silberg, Esquire Plant Superintendent Shaw, Pittman, Potts and Trowbridge Beaver Valley Power Station 1800 M Street, N.W.
P. O. Box 4 Washington, D. C.
20036 Shippingport, Pennsylvania 15077 Karin Carter, Esquire Mr. John A. Levin Special Assistant Attorney General Public Utility Commission Bureau of Administrative Enforcement P. O. Box 3265 5th Floor, Executive House Harrisburg, Pennsylvania 17120 Harrisburg, Pennsylvania 17120 Mr. J. D. Sieger, Superintendent Mr. Roger Tapan of Licensing and Compliance Stone and Webster Engic.eering Duquesne Light Company Corporation Post Office Box 4 P. O. Box 2325 Shippingport, Pennsylvania 15077 Boston, Massachusetts 02107 Mr. J. D. Woodward R & D Center Westinghouse Electric Corporation Building 7-303 Pittsburgh, Pennsylvania 15230 B. F. Jones Memorial Library 663 Franklin Avenue Aliquippa, Pennsylvania 15001 Mr. Jack Carey Technical Assistant Duquesne Light Company P. O. Box 4 Shippingport, Pennsylvania 15077 Mr. R. E. Ma rt i n Duquesne Light Company 435 Sixth Avenue Pittsburgh, Pennsylvania 15219 Marvin Fein Utility Counsel City of Pittsburgh 313 City-County Building Pittsburgh, Pennsylvania 15219
Encl h.re 1 UNITED STATES ISINS NO.:
6870 NUCLEAR REGULATORY C0K91SSION Accession No.:
OFFICE OF INSPECTION ANC ENFORCEMENT 7910250525 VASHINGTON, D.C.
20555 December 28, 1979 IE Information Notice No. 79-37
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C.i'CNING IN LOW PRESSURE TURBINE DISCS Oncriptica of Circumstances:
An anony..:ous let.ter was received by the Director of tb 2 Office of Inspection and Enfcroc. rent, 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 Vestinghouse 1800 rpm low pressure turbine discs.
htinghouse had cade 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 Novecter 20, 1979 established that cracking, attributed to stress corrosion phenc ena, 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-cented in the field.
The Office of Inspection and Enforcement was also notified on November 20, 1979 that during the current overha il of Corraonwealth 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 previcusly observed.
Ultrc-tonic r.cature.ents indicate this disc bore cracking is of greater dapth than the key,ay 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 dirc 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 aissile evaluation, inspection techniques and plant inspection priorities.
In response to th? staffs' request, Westinghouse provided the staf f an updated report on December 21, 1979 regarding the current field inspection program that included a list of nuclear power plants already inspected, recom-manded inspection schedules and pertinent information related to LP turbines wF are 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 ower o with a srall crack in the No. 2 di h tine, house indicated that the ob during 28 additional conths of tur DUPLICATE DOCUMENT the turbine inspection results and Entire document previously entered into system under:
ANO,
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