ML18033A274

Forwards Plant Program for Seismic Qualification of Drywell Steel for Review & Requests Issuance of Written Statement Documenting Programs Acceptability

ML18033A274
Person / Time
Site:	Browns Ferry
Issue date:	05/26/1988
From:	Gridley R TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML18033A276	List: ML18033A274 ML18033A277
References
TAC-00302, TAC-302, NUDOCS 8807180235
Download: ML18033A274 (7)

Text

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-P CCELEMTZD DISTRIBUTION DEMONSTRATION SYSTEM REGULATORY INFORMATION DISTRXBUTION SYSTEM (RIDS)

ACCESSION NBR:8807180235 DOC.DATE: 88/05/26 NOTARIZED: NO DOCKET FACIL:50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 AUTH. NAME AUTHOR AFFILIATION GRIDLEY,R. Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Requests review of encl program re drywell steel interim operability criteria. R DISTRIBUTION CODE: D030D COPIES RECEIVED:LTR TXTLE: TVA Facilities Routine Correspondence

/ ENCL J SIZE: ~/2 NOTES:S.Black 3 cy.1 cy. ea to: Ebneter,Axelrad,S.Richardson, 05000260 B.D.Liaw,K.Barr, OI.

8 RECIPXENT COPIES RECIPIENT COPIES <<jj ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL SIMMS,M 1 1 PD 1 1 A MORAN,D 1 1 GEARS,G 1 1 INTERNAL ACRS 1 1 ADM/LFMB 1 0 AEOD 1 1 NUDOG~BSTRACT 1 1 D

OGC 15-B-18 1 0 REG FIEE 01 1 1 EXTERNAL: LPDR 1 1 NRC PDR 1 1 NSIC 1 1 NOTES: 9 9 R,

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TOTAL NUMBER OF COPIES REQUIRED: LTTR 22 ENCL 20

TENNESSEE VALLEY AUTHORITY:

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5N 157B Lookout Place bO('NOTED USHRC ve Rs 1888 JIB "3 P):09 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:

In the Matter of Docket Nos. 50-260 Tennessee Valley Authority BROWNS FERRY NUCLEAR PLANT (BFN) SEISMIC QUALIFICATION OF DRYWELL STEEL-(NRC TAC NO. 00302)

This letter describes the BFN program for the seismic qualificati.on of drywell steel. This letter supplements the information provided by section III.3.8 of revision 1 to the BFN Performance Plan which was transmi.tted by S. A. White's letter dated July 1, 1987 and my letters, dated March 10, 1988 and April 28, 1988. This letter incorporates resolution of the NRC staff's concerns as discussed in our meeting, dated May 18, 1988.

Enclosure 1 to this letter describes the BFN program for resolving this issue. Enclosure 2 provides the BFN drywell steel interim operability criteria. TVA requests your review of this program and the issuance of a written statement documenting the programs acceptability.

Please refer any questions regarding thi.s submittal to M. J. May, Manager, BFN Site Licensing, (205) 729-3570.

Very truly yours, TENNESSEE VALLEY AUTHORITY R. ridley, D'ctor Nuclear Licensing and Regulatory Affairs Enclosures cc: See page 2 8807180235 880526 PDR 4DOCK 05000260 An Equal Opportunity Employer P PDC

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U.S. Nuclear Regulatory Commission MN 26 1988 cc (Enclosures):

Mr. K. P. Barr, Acting Assistant Director for Inspection Programs TVA Projects Division Office of Special Projects U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. G. G. Zech, Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Browns Ferry Resident Inspector Browns Ferry Nuclear Plant Route 12 P.O. Box 637 Athens, Alabama 35611

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ENCLOSURE 1 TENNESSFE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT UNIT 2 DRYWELL STEEL PLATFORMS This report gives TVA's plan to demonstrate the adequacy of drywell steel platforms.

Issue A nonconforming condition report identified an unanalyzed attachment to one of the lower drywell platforms. Investigation showed this to be part oE a generic problem fox all drywell platforms.

Blank round While dispositioning nonconEorming condition report BFN-BWP-8309, the following was determined: Drywell floor framing steel at elevations 563'nd 584'ad not been reevaluated Eor some loads which were added or revised since the original design, structural behavior oE platforms under combined loadings was not completely evaluated and documented, and some conEigurations did not match drawings. Additional findings were later identified in SCR BFN CEB 8634, 8640, and 8643 on platforms at elevations 604', 616', and 628'.

Resolution To assure the adequacy of drywell steel platforms, the following plan was implemented:

1. A detailed walkdown of all drywell platforms was performed to document the as-built configuration,

2. Detailed analysis of each platform was performed using the GT-STRUDL program. The model included primary as well as secondary steel that supports piping systems and cable trays. All support loads considex'ed were the maximum values Eor OBE and DBE load conditions. Resulting stresses were compared to an interim Operability Criteria based on the AISC code.

Platforms at elevations 604'; 616'; and 628'ave been evaluated to design critex'ia BFN 50-C-7100, revision 1, attachment G "Miscellaneous Steel Components for Class I and II Components."

3. Modifications are necessary to meet the interim operability criteria, on secondaxy steel beams and connections and were mainly due to safety relief valve piping loads. Additionally, stiEfener plates were added to reduce the local stresses in beams at attachment points.

4. Additional modifications were made to correct installation problems observed during the walkdowns.

5. All modifications necessary to meet operability criteria will be made pr'ior to restart of unit 2.

6. The FSAR requires that the drywell steel platfoxms remain Eunctional fox.

loads due to the platform weight and all attachment loads. Specific stxess allowables are identified in FSAR Table 12.2.16. These commitments are reflected in the design criteria for drywell steel platforms.

The drywell platform design will be brought up to the FSAR commitment post-restart incorpoxating final pipe. support attachment loads consistent with the schedule for completion oE the progxam to resolve IE Bulletin 79-14. Modifications required to meet design criteria will be implemented prior to restart following the next refueling outage.

To assuxe the structural adequacy of drywell platforms Eor future attachments, a long-term pxogram has been established to monitor and evaluate new attachments.

Licensin Issue The Interim Opexability Criteria used to determine the structural adequacy of dxywell platfoxms allows 1.6 times the capacity 'S'ased on the AISC code, instead of the FSAR stress limits oE 0.9Fy.

JustiEication The use of the Operability Criteria on an interim basis is considered justified because of the Eollowing:

1. The interim operability critexia minimizes the modifications in highly congested radioactive areas now, whi.le maintaining adequate industry accepted safety margins.

2. The long-term program provides fox updating the designs for the latest loads, resulting Erom the 79-14 program, and meeting the FSAR requirements.

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3. The operability criteria is based on NUREG 0800, Standard Review Plan, section 3.8.3, which has been accepted for use on other nucleax power plants. Also, the use oE the AISC code allowable stresses with appropriate load factors has been accepted by NRC fox the Torus Long Term Integrity program as documented in section 4-3.4 of the BFN Plant Unique Analysis Report (PUAR) which was transmitted by letter dated January 3, 1984, and as supplemented by submittals dated September ll, 1984 and January 25, 1985.

Approval of the BFN-PUAR is documented by letter from D. B. Vassallo to H. G. Parxis, dated May 6, 1985.

The drywcll steel qualification px'ogram is comprehensive and assures the structural adequacy of the drywell steel platforms.