ML18033A651

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Provides Corrections to Thermal Overload Heaters Sizing Criteria Submitted by TVA 880923 Ltr.Based on in-depth Evaluations & Discussions w/motor-operated Valve Mfgs,Tva Issued Quality Info Rept to Specify Listed Criteria
ML18033A651
Person / Time
Site: Browns Ferry Tennessee Valley Authority icon.png
Issue date: 02/28/1989
From: Gridley R
TENNESSEE VALLEY AUTHORITY
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TAC-62260-F, NUDOCS 8903080122
Download: ML18033A651 (6)


Text

CCPLERAyED DI~~BUTION DE M 04 STR+0~REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)ACCESSION NBR:8903080122 DOC.DATE: 89/02/28 NOTARIZED:

NO FACIL:50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee AUTH.NAME AUTHOR AFFILIATION GRIDLEY,R.

Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)DOCKET 05000260

SUBJECT:

Provides corrections to TOL heater sizing criteria submitted by TVA 880923 ltr.DISTRIBUTION CODE: D030D COPIES RECEIVED:LTR ENCL SIZE: TITLE: TVA Facilities

-Routine Correspondence NOTES:1 Copy each to: S.Black, J.G.Partlow, B.D.Liaw, F.McCoy 05000260 S RECIPIENT ID CODE/NAME SIMMS,M GEARS,G INTERNAL: ACRS NUDOCS-ABSTRACT 6~~01 EXTERNAL: LPDR NSIC NOTES COPIES LTTR E CL 1 1 RECIPIENT ID CODE/NAME PD ADM/LFMB OGC/HDS2 NRC PDR COPIES LTTR ENCL D S I D h NOTE m ALL<<RIDS>>RECIPIENIS:

PIZASE HELP US K)REDUCE HASTE!CXNI'ACZ'IHE DOCUMEN1'DÃHDL DESK, ROOM Pl-37 (EXT.20079)KO ELIMINATE RKR MQK HKH DISTEGBUTIGN LIPXS K)R DOCUMEM1'S YOU DON'T NEED!I TOTAL NUMBER OF COPIES REQUIRED: LTTR 15 ENCL l J r t TENNESSEE VALLEY AUTHORITY CHATTANOOGA.

TENNESSEE 37401 5N 1578 Lookout Place FEB RS 1383 U.S.Nuclear Regulatory Commission ATTN: Document Control Desk Hashington, D.C.20555 Gentlemen:

Docket No.50-260 In the Matter of)Tennessee Valley Authority)BRONNS FERRY NUCLEAR PLANT (BFN)-THERMAL OVERLOAD (TOL)HEATERS (TAC NO.62260-F)

Reference:

TVA letter to NRC dated September 23, 1988,"BFN-Response to Request For Additional Information

-Overload Protection of The Motor Control Center Circuits (TAC 62260-F)" This letter provides corrections to the TOL heater sizing criteria submitted by the referenced letter.Since that time TVA has revised the TOL heater-sizing criteria and calculation methodology.

This change was required based on evaluations of the Safety System Functional Inspection (SSFI)observations and nuisance trip problems experienced during the motor operated valve (MOV)operability verifications.

The SSFI inspection documented inadequacies in the application of TOL heater sizing criteria and manufacturer data in the sizing calculations.

These errors,,which were subsequently documented in a condition adverse to quality report, resulted in overly conservative motor, protection and insufficient margin for MOV operational loads.Based on indepth evaluations and discussions with MOV manufacturers, TVA has issued a Quality Information Report to specify the following criteria: Current l.200'/Nominal Torque Current (141'L Full Load Current)T~i5 ttl>duty cycle and<8 minutes (not applicable for dc)2.Locked Rotor Current a.ac b.dc a.<15 seconds (10 seconds preferred) b.<10 seconds 3903030i22 390223 PDR ADOCK 05000260 P PDC I An Equal Opportunity Employer 30 i)o l E U.S.Nuclear Regulatory Commission FEB RS'I%8 Use of this criteria along with proper application of manufacturer's data has resulted in larger size TOL heaters thus ensuring that motor operation is prioritized.

TVA has resized the TOL heaters and cycled those HOVs required for fuel load operations to ensure that nuisance tripping does not occur.Additionally, TVA will revise the calculations, resize the TOLs as appropriate, and cycle the other safety related HOVs before restart.The tracking and closure of the CAQR will ensure that the TOL heaters are properly sized and the sizing calculations are appropriately revised.If you have any questions, please telephone Patrick P.Carier, BFN Site Licensing, at (205)729-3570.Very truly yours, TENNESSEE VALLEY AUTHORITY cc: Hs.S.C.Black, Assistant Director for Projects TVA Projects Division U.S.Nuclear Regulatory Commission One Hhite Flint, North 11555 Rockville Pike Rockvi lie, Maryland 20852 Mr.F.R.HcCoy, Assistant Director for Inspection Programs TVA Projects Division U.S.Nuclear Regulatory Commission Region II 101 Harietta Street, NH, Suite 2900 Atlanta, Georgia 30323 Browns Ferry Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637 Athens, Alabama 35609-2000 R.'Cri ley, anager Nuclear Licensing and Regulatory Affairs t 8,"J 4.3C,