ML20207L899

Board Notification 86-025:forwards Safety Evaluation Rejecting Util Fracture Mechanics Methodology Used to Justify Tech Spec Change Request 148 Re Plugging Limits for once-through Steam Generator Tubes

ML20207L899
Person / Time
Site:	Three Mile Island
Issue date:	12/23/1986
From:	Thoma J Office of Nuclear Reactor Regulation
To:	Paris O, Shon F, Wolfe S Atomic Safety and Licensing Board Panel
Shared Package
ML20207L900	List: ML20207L899 ML20207L920
References
CON-#187-2149, TASK-AS, TASK-BN86-025, TASK-BN86-25 BN-86-025, BN-86-25, OLA-OLA-2, NUDOCS 8701130025
Download: ML20207L899 (4)

Text

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+N g December 23, N Docket No. 50-289 MEMORANDUM FOR: The Atomic Safety and Licensing Board for Three Mile Island, Unit 1 (S. J. Wolfe, 0. H. Paris, F. J. Shon)

FROM: John Thoma, Project Manager PWR Project Directorate #6 Division of PWR Licensing-B Office of Nuclear Reactor Regulation

SUBJECT:

BOARD NOTIFICATION REGARDING TMI-1 PLUGGING LIMITS FOR ONCE THROUGH STEAM GENERATORS (TSCR 148) AND USE OF FRACTURE MECHANICS METHODOLOGY (BN-86-25)

The enclosed Safety Evaluation (SE) is being provided to the Board because it is applicable to Technical Specification Change Request (TSCR) 148 which concerns once through steam generator (OTSG) tube plugging limits for TMI-1.

Parties to the proceeding are being informed by copies of this memorandum.

By a filing dated July 28, 1986, titled "NRC Staff Response To Licensee's Motion for Deferral of Hearing Schedule", the NRC staff stated its intention to issba a single Safety Evaluation Report (SER) addressing TSCR 148 by January 31, 1987, or about four weeks after Licensee submits analysis of the OTSG tube test results, whichever is later. The basis for this statement was an understanding that a final,SER could not be issued until after tube samples were drawn and analyzed.

For issues in contention before the Board, it is still the NPC staff's position that a final SER cannot be produced until the tube analyses are complete. However, after several extensive discussions with the Licensee and further review of TSCR 148 and supporting information, the NRC staff has concluded that it will deny TSCR 148 based solely on considerations outside of those under contention before the Board and regardless of tube analysis results. Enclosed for the Board's information is the NRC staff's SE which rejects the fracture mechanics methodology used by the Licensee to justify this amendment.

In the staff's SE, we conclude that the elastic-plastic fracture mechanics and net section collapse analyses performed by the Licensee in support of the

proposed steam generator tube plugoing limit criteria are not adequate to demonstrate that such criteria will meet the factors of safety recommended by Regulatory Guide 1.121. Neither does the Licensee offer an acceptable alternative to the safety factors of Regulatory Guide 1.121. Specific weaknesses in the Licensee's submittal include the following

! 1. As input to the fracture mechanics analyses, GPUN used axial tube loads, for normal operating and faulted c.onditions, that were obtained from a P&W i topical report which has not been reviewed or approved by the NRC.

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/ 2. GPUN incorrectly inserted non-linearly derived loads and stresses into a linear elastic calculational procedure.

3. Bending loads due to flow induced vibration during a main steam line break have not been addressed.

4. The tube material true stress-true strain curve estimation procedure was not validated.

5. GPUN did not demonstrate that the use of data from 304 stainless steel with a power fit law is conservative for the actual tube material (Inconel 600).

6. GPUN did not demonstrate that the derived J-R curve is representative of the tube and flaw geometry.

7. GPUN's value for flow stress, a critical factor in the analysis, is non-conservative when compared to proven material yield and ultimate strengths at temperature.

8. GPUN's analyses do not show that recommended safety margins of Regulatory Guide 1.121 are met for flaws greater than 60 percent throughwall. GPUN also does not provide a detailed technical justification for an alternatiye approach to the safety margins of Regulatory Guide 1.121. -

The issues of contention before the Board relate to eddy current uncertainty and potential effects of future corrosion on determining tube plugging limits. As outlined above, the NRC staff is rejecting the amendment based on issues different from the contentions (i.e., the Licensee has not met the recommended safety margins in Regulatory Guide 1.121 or provided satisfactory alternatives). It should be specifically noted that the enclosed SE does not address any area of contention in the hearing, although it is relevant to the proceeding. The enclosed SE was issued on December 23, 1986.

/S/

John Thoma, Project Manager l PWR Project Directorate #6 Division of PWR Licensing-B Office of Nuclear Reactor Regulation i

Enclosure:

l As stated cc w/ enclosure:

See next page *See previous white for concurrences 1

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Mr. Henry D. Hukill Three Pile Island Nuclear Station, GfuNuclearCorporation Unit No. I cc:

Mr. R. J. Toole Mr. Richard Conte O&M Director, TMI-1 Senior Resident Inspector (TMI-1) )

GPU Nuclear Corporation U.S.N.R.C.

Middletown, Pennsylvania 17057 P.O. Box 311-

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Middletown, Pennsylvania

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17057 l Richard J. McGoey '

Manager, PWR Licensing Regional Administrator, Region I GPU Nuclear Corporation U.S. Nuclear Regulatory Conunission  !

100 Interpace Parkway 631 Park Avenue Parsippany, New Jersey 70754 King of Prussia, Pennsylvania 19406 Mr. C. W. Smyth Mr. Robert B. Borsum TMI-1 Licensing Manager Babcock & Wilcox GPU Nuclear Corporation Nuclear Power Generation Division

, P. O. Box 480 . Suite 220, 7910 Woodmont Avenue.

Middletown, Pennsylvania 17057 Bethesda, Maryland 20814

Ernest L. Blake, Jr., Esq. Governor's Office of State Planning Shaw,.Pittman, Potts & Trowbridge and Development 2300 N Street, N.W. ATTN: Coordinator, Pennsylvania Washington, D.C. 20037 State Clearinghouse '

P. O. Box 1323 Sheldon J. Wolfe, Esq., Chairman Harrisburg, Pennsylvania -17120 '

Atomic Safety and Licensing Board U.S. Nuclear Regulatory Commission Mr. Larry Hochendoner Washington, D.C. 20555 Dauphin County Commissioner Dauphin County Courthouse Mr.~ Frederick J. Shon Front and Market Streets Atomic Safety and Licensing Board Harrisburg, Pennsylvania 17101 U.S. Nuclear Regulatory Commission

, Washington, D.C. 20555 Mr. David D. Maxwell, Chairman Board of Supervisors

Dr. Oscar H. Paris Londonderry Township

'. Atomic Safety and Licensing Board RFD#1 - Geyers Church Road t .U.S. Nuclear Pegulatory Commission Middletown, Pennsylvania 17057 Washington,'D.C. 20555 Pr. Thomas M. Gerusky, Director Atomic Safety & Licensing Board Panel Bureau of Padiation Protection U.S. Nuclear Regulatory Commission Pennsylvania Department of Washington, DC 20555 Environmental Resources P. O. Box 2063 Atomic Safety & Licensing Appeal Harrisburg, Pennsylvania 17120 Board Panel (8)

U.S. Nuclear Regulatory Commission Thomas Y. Au, Esq.

Washir.gton, D.C. 20555 Office of Chief Counsel Department of Environmental Resources c Docketing and Service Section 505 Executive House Office of the Secretary P. O. Box 2357 U.S. Nuclear Regulatory Commission Harrisburg, Pennsylvania 17120 Washington, D.C. 20555 Ms. Louise Bradford TMIA 1011 Green Street Harrisburg, Pennsylvania 17102

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Mr. Henry D. Hukill -

2- Three Mile Island Nuclear Station GfuNuclearCorporation Unit 1 TMIA 315 Peffer Street Harrisburg, Pennsylvania 17102 Bruce W. Churchill, Esq.

Shaw, Pittman, Potts & Trowbridge 2300 N Street, N.W.

Washington, D.C. 20037

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