ML092440518

08/07/2009 TVA Conference Call Presentation Slides on Browns Ferry Nuclear Plant, Unit 1 Steam Dryer Analysis

ML092440518
Person / Time
Site:	Browns Ferry
Issue date:	08/07/2009
From:	Tennessee Valley Authority
To:	Office of Nuclear Reactor Regulation
Brown E, NRR/DORL, 415-2315
Shared Package
ML092440524	List: ML092430520 ML092440518
References
TAC MD5262
Download: ML092440518 (14)

Text

TENNESSEE VALLEY BROWNS FERRY NUCLEAR UNIT Steam Dryer August

[II]Steam Dryer Stress Analysis

• Low Flow Noise Included

• Re-analyzing Steam Dryer Stress Show SR > 2.0 -As built steam dryer at 110% OL TP -Modified steam dryer at 1200/0 OL TP 2

[II]Steam Dryer Stress Analysis

• 1100/0 OL TP Based on CDI 08-15P (March 2009) with: -Low flow noise included -Adjusted bump-up for 1100/0 v 2 & 110% resonance

-Same steam dryer configuration

-Utilization of ASME Table NG 3352-1 -SR > 2.0 3 iii]Steam Dryer Stress Analysis

• 120% OL TP Based on COl 08-15P 2009) -Low flow noise

-Additional steam dryer

-Revision of two o 1 SIA-1-Utilization of ASME Table NG -SR > 4

[II]Steam Dryer Stress Analysis z y index I Outer Hood -Old & Lock Group Drain Group Inner Hood Group 5 Steam Dryer Stress Analysis Middle Hood/F&T Tie Group Outer Hood Side Panel Vane Bank End Group Outer Bank Discharge End panel Middle Hood I Top Group 6 III]Steam Dryer Stress Analysis Noise Retained Modifications Old Tie Bar/Lock Gusset Reinforcing Bar ole Replace with TVA Gusset Group I lli; i 't:! ,. * ; -.L 3t L Drill Yo" DIA lie Two (2) lJUssets are "'ll\lired per C-vssel Pad s:eam dam. four (-4) iotal per unit.

n Existing Configuration at 4 Locations, Where Old TB Remnant and Lock Gusset Were Retained.

L/Stress Intensities Seen in Base Plate, TB 1 Connection

& Lock Gusset Connections.

Mod Removes this Configuration and Replaces with Revised Gusset as Found in all other Locations, Stiffens the top of Steam Dam with a Pipe Section, & Reinforces the %" Thick Outer STEAM DAM GUSSET ASSEMBLY Hood Cover. PATCH PLATE DETAILS -BFN U1 7 Steam Dryer Stress Analysis Noise Retained Modifications Inner Hood Stiffeners

-Group II Limiting stress location is at bottom corner of Hood Stiffener 2 sided fillet weld. Addition of stress relief semi-circular hole reduces stress acting on weld and adds flexibility to corner. Modifications provide a SRF = Previous Solid Sub Model Revised to Evaluate Stress Relief and Resultant SRF HOOD SlIPPORT .2:5 I ! 3.f1E 3,1 ! 000-TO-HOOD SUPPORT RELIEF HO ASEUNE DIMENSIONS 8

[iI]Steam Dryer Stress Analysis Noise Retained Modifications Drain Channels -Group III DC Follow the Dryer Skirt Modal Response.

Limiting Stress Location is at Bottom of Drain Channel Weld, that has been Already Reinforced and Wrapped Underneath the DC. Addition of Stress Relief Semi-circular Hole Reduces Stress Acting on Weld and Adds Flexibility to Corner. Modifications Provide SRF =.43 Previous Solid Sub Model Revised to Evaluate Stress Relief and Resultant SRF 1Ia" Drain el(ref}j J'ttt R 3.50 (lef l-\ ! A ----114" Dryer Skirt (reI)__ 18" [)fain Ch01f1nel (reI) _ Semi-circu 'Nolie: These dimensi:>ns are g;ven as arc along .!he O'..I"V3".ure of Section A-A drain Ch01f1 DRAIN CHANNEL END RELIEF HOLE CONCEPT 9

[iJJ Steam Dryer Stress Analysis Noise Retained Modifications 6 This n:et::h is appbcable only co lie bars spanning the ci;scharge duc.-:s. 4 reauired.

.... ----Middle Hood/F&T Tie Bar -Group IV One location, between outer and middle banks, has a high stress located under the tie " bar in the weld to the hood section. Additional reinforcement using a reinforcing plate and additional welds is to be added. Vane Rank A total of four (4) symmetrical locations will be Cover (rei) modified. [7/0-Max ,__ .. __.-- See FW'e 'j ,I. 6" *1 (ref) C FLARED &TAPERED TIE BAR OUTER VANE BANK DISCHARGES See OU.:er Tie Bar-to-Hood Reinroreement DetI:iI Shee, 8,80t:om comers be rounded to 0.25" maximum rallYs 'thin % 1 inc:ll 01 flare break line to {aciSta:e welding. 1**1 l' Surfac.e may be m.a.chined a requ'red ior lihlp if vane bank to hood offsl!l is Iessthill 114'_ 10 Steam Dryer Stress Analysis Noise Retained Modifications Outer Hood Side Panel / Vane Bank End Wall Group V Limiting Component is the 3/8" thick Vane Bank End Closure Plate. Structural Thickness Changes Of Drain Trough, behind Plate, Contribute to Stress Intensity.

Mod Provides Reinforcement to Distribute Stress 318" x Reinfordng "7 3/8" Vane 3/8" Outer Hood L--End Plate (ref) Closure Plate (ref) Bf 1/4" Vane Bank Outlet Skle Trough Plate (ref) 1/2" x 6-1/2' Trough Upper Ring (ref) C ReinforCing Plate, Both SiOes (re.f) 1/2" Vane Bank Bottom Plate (ref) End View -Outer Hood Closure-to-Vane 1/2" x 6-1/2' Trough Reinforcing Plate (ref) 318" Vane Bank End Plate (ref) 316 .., 2' x 318" thk x 24" Ig Reinfordng Bar 318" Hood Closure Plate (ref) --'..., I lY Section A-A (Cut Thru Trough) Section B-B (Cut Thru Perforated Plate) 11

[II]Steam Dryer Stress Analysis R 0.25 (TVP) Noise Retained Modifications

+ Outer Bank Discharge End /Middle Hood/ Top Group VI Limiting stress is in the 1f4" thick hood cover plate and 1f4" attachment fillet weld. Mod provides additional reinforcement, additional 3.00 weldment, and stiffening.

B oJ! ,_,"_ ..LJ-L- MIDDLE HOOD/COVER PLATE/END CLOSURE REINFORCING GUSSET 0.25 0.75 SECTION B-B 12

[II]Steam Dryer Stress Analysis -Interim Operation at Limited Power o Based on stress analysis at 11 OL TP with currently modified steam dryer o Low flow noise included o SR > 2.0 o Implement mid-cycle

-Operation at 120% OL TP after Additional Steam Dryer Modifications o Based on stress analysis at OL TP with additional modifications to steam dryer o Low flow noise included o SR > 2.0 o Implement modifications Fall 2010 13

[II]Steam Dryer Stress Analysis Planned Submittals

-110 % OL TP o Load report o Stress report o Limit -120% o Load report o Stress report o Limit curves o Submodels

-Submittal by August 28 14