ML20217D934

Informs That NRC Staff Has Accepted Deferral of Completion of Certain Actions Requested by Bulletin 96-03, Potential of Plugging of ECCS Strainers by Debris in Boiling Water Reactor

ML20217D934
Person / Time
Site:	Browns Ferry, Oconee
Issue date:	09/22/1997
From:	Williams J NRC (Affiliation Not Assigned)
To:	Kingsley O TENNESSEE VALLEY AUTHORITY
References
IEB-96-003, IEB-96-3, TAC-M96135, TAC-M96136, TAC-M96137, NUDOCS 9710060221
Download: ML20217D934 (4)

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, g NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 30468 4 001 k*.... September 22, 1997 Mr. Oliver D. Kingsley, Jr.

President. TVA Nuclecr and Chief Nuclear Officer Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga. Tennessee 37402 2801

SUBJECT:

BROWNS FERRY NUCLEAR PLANT UNITS 1. 2. AND 3 - RESPONSE TO BULLETIN 96 03 (TAC NOS. M96135. M96136. AND M96137)

Dear Mr. Kingsley:

The Nuclear Regulatory Commission (NRC) staff has accepted deferral of com)letion of certain actions requested by Bulletin 96 03. " Potential Plugging of Emergency Core Cooling System (ECCS) Strainers by Debris in Boiling Water Reactors " for the Browns Ferry Nuclear Plant (BFN) Unit 2 until December 31.

1998, or until NRC approval and TVA implementation of a license amendment incorporating containment overpressure credit for ECCS pump net positive suction head (NPSH) into the licensing basis, whichever is first.

On July 25. 1997 the Tennessee Valley Authority (TVA) provided a supplemental response to B 96 03. BFN Units 1. 2. and 3. Based on its initial review of this supplemental response, the NRC staff determined that portions of TVA's response appear to constitute an unreviewed safety question under the provisions of 10 CFR 50.59. If an unreviewed safet staff review and approval of those portions of TVA'ysquestion responseexists. NRC is required prior to implementation.

Specifically. TVA's July 25, 1997 letter states that containment overpressure is being credited to ensure adequate NPSH for low pressure ECCS systems.

Containment overpressure credit for NPSH is not currently part of the BFN licensing or design basis. The NRC staff believes that incorporation of containment overpressure credit into the licensing basis increases the possibility of malfunction of equipment important to safety. In addition, the margin of safety implicit in the requirements for ECCS pump operability may be reduced. Therefore, the NRC staff considers credit for containment overpressure for ECCS pump NPSH to be an unreviewed safety question. This position is consistent with that expressed by the NRC staff in a meeting with the Boiling Water Reactors Owners Group on February 19, 1997. This position was verbally discussed with members of y a r staff shortly after NRC receipt of your July 25, 1997 letter. \gl'0I

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On August 25, 1997. TVA pr posed to com)lete installation of the upgraded ECCS suction strainers during the upcoming B N Unit 2 refueling outage. TVA stated that it is preparing a license amendment to incorporate containment I

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overpressure into the licensing basis. Review of this license amendment will provide for NRC approval of the unreviewed safety question prior to its implementation in the BFN licensing basis, 9710060221 970922 DR ADOCK 0500 9 ['

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. f Mr. O. D. Kingsley 2- l TVA proposed to defer incorporstion of the containment overpressure credit '

until December 31, 1998, or until NRC staff approval of the associated license  !

amendment, whichever is sooner. TVA committed to maintain its foreign i material exclusion program, to perform thorough inspections to ensure  !

insulation is securely fixed and to verify that all foreign material has been  !

removed from the dr pool if necessary. ywell and Deferral of suppression incorporation ofpool, and to desludge the containment the suppression overpressure credit permits restart of BFN Unit 2 from the upcoming refueling outage with the upgraded ECCS suction strainers under the current licensing basis.

t The NRC staff finds that installation of the new suction strainers substantially improves the ability of the plant to acconynodate debris .

blockage, and that TVA's compensatory measures provide assurance that-debris loading will be maintained as low as practical. Therefore, the NRC staff.

accepts deferral of updating the BFN Unit 2 licensing basis to incorporate the containment overpressure credit in NPSH calculations consistent with 8 96 03 Option 1 until December 31, 1998, or until NRC approval and TVA implementation of the associated license amendment, whichever is first. '

You should be aware that similar situations have been identified for other

• boiling water reactors which also require license amendments. The NRC staff believes that TVA should have been aware of these activities, and should have been prepared to provide a proposed license amendnent as part of its supplemental response to B 96 03. without being prompted by the staff.

Questions regarding the acceptability of. the proposed amendment and the ,

schedule for im)1ementation could also have been resolved in a more timely manner had TVA yeen able to maintain its oririnal May 1997 schedule for providing its B 96 03 supplemental response. -

TVA's license amendment request should includ4 information similar to that provided by the licensees for the Dresden Mcelcello, and Pilgrim plants. .

Items =of interest to the NRC staff include, bu' are not limited to, details of .

NPSH and minimum containment pressure calculations including all assumptions and models used, time dependent NPSH required vs. NPSH available, and performance of containment spray'or other pressure mitigating safeguards.

Please call me at (301)415 1470 if you have any questions regarding this topic, Sincerely, , ,

. m

/ Joseph ProjectF.Directorate Williams, Project 11 3 Manager-Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50 259, 50 260, and 50-296 cc: See next page

l Mr. Oliver D. Kingsley, Jr. P"0WNS FERRY NUCLEAR PLANT Tennessee Valley Authority CC Mr. O. J. Zeringue, Sr. Vice President Mr. Mark J. Burzynski, Managar Nuclear Operations Nuclear Licensing Tennessee Valley Authority Tennessee Valley Authority 6A Lookout Place 4J Blue Ridge 1101 Market Street -1101 Market Street Chattanooga, TN 37402-2801 Chattanooga, TN 37402-2801 Mr. Jack A. Bailey, Vice President Mr. Timothy E. Abney, Manager Cngineering & Technical Services Licensing and Industry Affairs Tennessee Valley Authority~

Browns Ferry Nuclear Plant 6A Lookout Place Tennessee Valley Authority 1101 Market Street P.O. Box 2000 Chattanooga, TN 37402-2801 Decatur, AL 37402-2801 Mr. C. M. Crane, Site Vice President Regional Administrator, Region 11 Browns Ferry Nuclear Plant U.S. Nuclear Regulatory Commission Tennessee Valley Authority 61 Forsyth Street, SW., Suite 23T85 P.O. Box 2000 Atlanta, GA 30303-3415 Decatur, AL 35609 Mr. Leonard D. Wert General Counsel Senior Resident Inspector Tennessee Valley Authority U.S. Nuclear Regulatory Commission ET 10H Browns Ferry Nuclear Plant 400 West Summit Hill Drive 10833 Shaw Road Knoxville, TN 37902 Athens, AL 35611 Mr. Raul R. Baron, General Manager State Health Officer Nuclear Assurance Alabama Dept. of Public Health Tennessee Valle.1 Authority 434 Monroe Street 40 Blue Ridge Montgomery, AL 35130-1701 1101 Market Street Chattanooga, TN 37402-2801 Chairman Limestone County Commission Mr. Karl W. Singer, Plant Manager 310 West Washington Street Browns Ferry Nuclear Plant Athens, AL 35611 Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609

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,Mr. O. D. Kingsley September 22, 1997 TVA proposed to defer incorporation of the containment overpressure credit until December 31. 1998, or until NRC staff approval of the associated license amendment, whichever is sooner. TVA committed to maintain its foreign material exclusion program, to perform thorough inspections to ensure insulation is securely fixed and to verify that all foreign material has been removed from the drywell and suppression pool, and to desludge the suppression pool if necessary. Deferral of incorporation of the containment overpressure credit permits restart of BFN Unit 2 from the upcoming refueling outage with the upgraded ECCS suction strainers under the current licensing basis.

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The NRC staff finds that installation of the new suction strainers substantially improves the ability of the plant to accommodate debris blockage, and that TVA's compensatory measures provide assurance that debris loading will be maintained as low as aractical. Therefore the NRC staff accepts deferral of updating the BFN Jnit 2 licensing basis to incorporate the containment overpressure credit in NPSH calculations consistent with B 96-03 Option 1 until December 31, 1998, or until NRC approval and TVA implementation of the associated license ament.nent, whichever is first.

You should be aware that similar situations have been identified for other boiling water reactors which also require license amendments. The NRC staff believes that TVA should have been aware of these activities, and should have been prepared to provide a proposed license amendment as > art of its supplemental response to B 96-03 without being prompted )y the staff.

Questions regarding the acceptability of the proposed amendment and the schedule for im)1ementation could also have been resolved in a more timely manner had TVA )een able to maintain its original May 1997 schedule for providing its B 96-03 supplemental response.

TVA's license amendment request should include information similar to that provided by the licensees for the Dresden. Monticello, and Pilgrim plants.

Items of interest to the NRC staff include, but are not limited to details of NPSH and minimum containment pressure calculations, including all assumptions and models used, time-dependent NPSH-required vs. NPSH-available, and performance of containment spray or other pressure-mitigating safeguards.

Please call me at (301)415-1470 if you have any questions regarding this topic.

Sincerely.

Joseph F. Williams. Project Manager Project Directorate 11 3 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket Nos. 50-259. 50-260.

and 50-296 cc: See next page DISTRIBU.Il0N:

Docket File FHebdon ACRS RElliott BClayton PUBLIC KKavanagh JJohnson. Ril BFN Reading BBoger OGC DOCUMENT NAME: G:\BFN\M96135.US0 *see previous concurrence To receive a copy of this document, indicate in the box: "C" - Copy without attachment / enclosure "E" - Copy with attachment / enclosure "N" - No copy OFFICE P0ll*3/PM /jp lC PDil*3/LA a. lCl SCSB l6 SRXB l C- 0:PDil*3 g) i NAME JWi t t isms t mw /W BClayt on 9'~ CBerlinger* TCottins* FMehdon i-f DATE 09/ 4 J97 /'/ 09/rW/97 '

09/12/97 09/17/97 09/11/97 0FFICIAL RECORD COPY