ML081130231

Public Slides - Summary of April 17, 2008, Meeting Regarding Steam Dryer Portion of the Extended Power Uprate Review,

ML081130231
Person / Time
Site:	Browns Ferry
Issue date:	04/17/2008
From:	Structural Integrity Associates, Tennessee Valley Authority
To:	Office of Nuclear Reactor Regulation
Brown Eva, NRR/DORL, 415-2315
Shared Package
ML081420138	List: ML081120502 ML081130231 ML081360291
References
TAC MD5262, TAC MD5263, TAC MD5264
Download: ML081130231 (43)

Text

Non-Proprietary Information JIVAJ TENNESSEE VAL LEYdAUTH ORITY BROWNS..FERRY NUCLEAR PLANT

• Von Apri -17'.08

-Ly

• 2t.

Non-Proprietary Information ftAj Agenda

• Status

• Modifications Overview

• Margin Demonstration

• Hydrodynamic Damping

• Noise Reduction

• Additional Questions from March 20 Meeting

• Schedule 2

Non-Proprietary Information Status IRA I

• Analyses for Units 1 and 2 submitted Unit 3 analysis will be submitted June 16 RAI Round 15 & 16 responses provided

• Additional questions from March 20 meeting and Round 17 RAIs 3

Non-Proprietary Information Modifications Overview Planned/Completed Modifications Reinforcement of drain channel welds to 1/4" fillet, wrapped around bottom channel corner Replacement of tie-bars with new design Reinforcement of undersize welds for full thickness (cover plate, corner plates, & manway locations)

Steam path frequency suppression with Acoustical Vibration Suppressor (AVS) in blind flanged standpipes (removes 218 Hz resonance)

• Modifications Now Being Planned Steam dam gussets Steam path frequency suppression with Acoustical Side Branch (ASB) to mitigate SRV resonance being investigated at 110 Hz 4

Non-Proprietary Information Margin Demonstration

• Common understanding of margin expectation SR-a > 2.0 at EPU (CLTP scaled up)

For BFN; SR-a > 2.7 at CLTP

• Review of limiting locations (SR-a < 2.7) 14 locations on Unit 1 7 locations on Unit 2

• Simplified modeling of welded joints Weldment not modeled Generic 1.8 weld factor

• More refined treatment of welds Model weld geometry in detail Weld factor specific to weld

• Dryer Modifications 5

Non-Proprietary Information Unit 1 Limiting Locations Family Srank Node Description SRaReouinApac RakCurrentReouinApac 1

88059 Top Cover Over Vane Bank Perf Plate 1.56 Investigate reduced weld factor using detailed solid element Between the Toes of Adjacent Tie Bar Pads substructure model that includes fillet welds.

2 107054 Top Cover at Heel of Tie Bar Pad 1.59 If reduced weld factor does not provide sufficient margin 3

102407 Top Cover at Toe of Tie Bar Pad 1.62 (SRa >2.7 @ CLTP), pursue modification concept.

Tie Bar 912 Top Cover Over Van Bank Perf Plate Near Potential Modification Concepts:

940 Toe of Tie Bar Pad 1.63 Localized reinforcement around fillet weld Modified tie bar to reduce eccentricity (prying action) 6 96561 Top Cover at Heel of Tie Bar Pad 1.94 Additional tie bars 10 103094 Top Cover at Long Edge of Tie Bar Pad 2.28 5

1034 Steam Dam Lock Gusset at Contact Point 1.8 Pursue modification via additional gussets similar to original 1034 with Tie Bar (not weld joint) 1.8 dryer gussets. Dryer model will be adjusted to disconnect lock 7

103088 Steam Dam to Top Cover Joint 1.98 gusset from tie bar.

Dam 9

102521 Steam Dam at Top of Lock Gusset 2.19 11 103089 Steam Dam to Top Cover Joint 2.4 12 93824 Steam Dam to Top Cover Joint 2.56 14 103082 Steam Dam to Top Cover Joint 2.67 Drain 8

1059 Drain Channel To Skirt Joint at Bottom of 2.5 Investigate reduced weld factor using detailed solid element Channel 1059 Channel 2.5 substructure model that includes actual configuration.

Hod 13 964 Inner Hood To Hood Support Joint at 2.2 Investigate reduced weld factor for double fillet configuration.

Hoo 9454 Bottom of Hood 2.2 This location is inaccessible.I 6

Non-Proprietary Information Unit 2 Limiting Locations N

Family Srank Node Description SRaReouinApac RakCurrentReouinApac 1

96745 lop Cover/Top Tie Bar Base Thick 1.65 Investigate reduced weld factor using detailed solid element substructure model that includes fillet welds.

2 88313 lop Cover Inner Hood/Top Cover 1.86

_______Overlap/Top Perf Plate If reduced weld factor does not provide sufficient margin 3

97260 lop Cover/Top Tie Bar Base Thick 1.98 (SRa >2.7 @ CLIP), pursue modification concept.

Tie Bar 4

107776 Top Cover/Top Tie Bar Base Thick 2.38 Potential Modification Concepts:

Localized reinforcement around fillet weld 5

100330 lop Cover Inner Hood/Hood Support/Top 2.44 Modified tie bar to reduce eccentricity (prying action)

Tie bar Base Thin Additional tie bars 7

107924 lop Cover Middle Hood/Top Perf 2.56

_________________Plate/Top Cover Overlap Mid Plate 6

88299 Mid Plate/Top Tie Bar Mid 2.48 Bearing load Notch.III 7

Non-Proprietary Information Tie bar Unit 1 Location #1 H -ftA Node 88059 8

Non-Proprietary Information Tie bar Unit 1 -Location #2 JRAJ Node 107054 9

Non-Proprietary Information Tie bar Unit 1 Location #3 H -ftA Node 102407 10

Non-Proprietary Information Tie bar Unit 1 Location #4 SR-a "#Id) 2.7 2.8 2.5 2A 2.3 2.2 21t 2

1.8 1.7 I.5 Node 91420 11

Non-Proprietary Information Tie bar Unit 1 Location #6 H -ftA F

S R-a s (Wdk 2.7 2.8 2.4 2.3 2.2 2.1 2

1.9 1.8 11 I.8 1.5 Node 96561 12

Non-Proprietary Information Tie bar Unit 1 Location #10 SR-a (weld) 2.7 2.6 2.5 2A 2.2 2.1 2

1.9 1.8

1. 7 is6 Node 103094 13

Non-Proprietary Information Tie Bar

• Detailed weld

• Configuration known from VT-1 inspection 14

Non-Proprietary Information Dam Unit 1 Location #5 I-RAI Node 107394 15

Non-Proprietary Information Dam Unit 1 Location #7 JRAJ z

Y x

SR-a (weld) 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2

19 1.7 1.8ý,

Node 103088 16

Non-Proprietary Information Dam Unit 1 Location #9 JRAJ x Y Node 102521 17

Non-Proprietary Information Dam Unit 1 Location #11 ljw z

Sy x

SR-a w#Md) 2.7 218 2A 2,3 2.2 21 2

1.:

1'. 87 Node 103089 18

Non-Proprietary Information Dam Unit 1 Location #12 IM z

SY x

a (wow) 2.7 2.5 2.5 2A 2.3 2.2 2A 2

1.9 is 1.7 Node 93824 19

Non-Proprietary Information Dam Unit 1 Location #14 lfw z

x

ýs e#.id 2.7 2.6 2.4 2.3 2.2 2.1 2

1.

1.87 Node 103082 20

Non-Proprietary Information Dam Addressed by modification to add additional steam dam gussets 21

Non-Proprietary Information Drain Channel Unit 1 Location #8 Node 104539 22

Non-Proprietary Information Drain Channel JRAJ

" Apply specific weld factor Reinforced drain channel welds wrapped around bottom channel corner

• Configuration known from VT-1 inspection Original

, weld Reinforced weld Drain Channel Wrap the vertical weld reinforcement 23

Non-Proprietary Information Hood Unit 1 Location #13 IM Node 94654 24

Non-Proprietary Information Hood IM

• Apply specific weld factor Fillet weld both sides

• Configuration known from VT-1 inspection

-i--

1/4" thk. pit.

1/*" fillet weld, both sides I

I Unit 1 node 94654 25

Non-Proprietary Information Margin Demonstration N

• Structural Integrity Associates, Inc.

Evaluation of Stress Concentration in the Browns Ferry Steam Dryer 26

Non-Proprietary Information Margin Demonstration Welds on Browns Ferry Steam Dryer Original activity o Fabrication drawings o PT - steam dams & gussets; vane banks o VT-hood joints Recent Modification activity o Performed to GE Installation Specification

[]

In accordance with ASME 2001,Section Xl, IWA 4660 o

Entire length of weld inspected. Weld height and throat thickness verified by weld gage.

o New tie bar subassemblies PT Inspection recorded with video equipment 27

Non-Proprietary Information 2]

28

Non-Proprietary Information JRAJ 29

Non-Proprietary Information JRAJ 30

Non-Proprietary Information Noise Floor JRAJ

" Low flow strain gage data used to remove non-acoustic sources Unit 1 @ 9% power Unit 2 @ 19% power Unit 3 data to be taken during startup Noise signal filtered and processed by ACM Removed at MSL inlet Results provided in CDI stress reports Minimum stress ratio Noise Retained Noise Removed Unit 1 1.21 1.56 Unit 2 1.59 1.65 31

Non-Proprietary Information IM 32

Non-Proprietary Information IVA]

33

Non-Proprietary Information IM 34

Non-Proprietary Information Additional Questions

" Mesh Discretization Bias Staff disagrees that mesh discretization is subsumed by uncertainty associated with shaker tests In draft Hope Creek EPU Safety Evaluation, NRC accounts for the additional 3.8 percent bias error In future analyses for BFN, 3.8 percent bias error from mesh discretization will be added

" Perforated Plate Mode Shapes

• Accumulative PSD vs Stress 35

Non-Proprietary Information JRAJ 36

Non-Proprietary Information Schedule 11VA11 Weld Factor Evaluation 5/1,5 Ul Sub Model Revised U1 Calcs Stress Tables 5/15 5/22 NRC Submittal

& Review 5/23 U2,3 Sub Model Revised U2,3 Calcs Stress Tables 5/15 5/22 Modification to FEMs Steam Dam Ul FEM Unit Solutions 0

0 5/22 6/5 Revised Ul Stress Analysis i

NRC Submittal

& Review U2,3 FEM Unit Solutions Revised U2 Stress Analysis U3C13 0

5/4 U3MSL U3 CLTP Data Load 0 -- 0 NRC Submittal

& Review 5/9 5/11 5/21 6/5 6/10 6/15 37

Structural Integrity Associates, Inc.

h/

F ation of the Brown's Ferry (BF) steam performed using three-dimensional-fi nite int model Oil elements, used for evaluation ood repIresentation of overall behavior Id "factors" are applied to results from shell del to incorporate the weld and stress centration for fatigue evaluation

-actors obtained from standard sources Factor of 1.8 calculated for Brown's Ferry Stiructural Integrity Associates, Inc.

y kg:roun-d evaluation can support characterization of to i refined results -

eling can include specific

,try an~d. provide further insight evaluating the results using mesh sensitive a function of -the type of Structural Integrity Associates, Inc.

rowns Ferry Weld Evaluation

'*.ess in the hood and drain channel stress ocations will be evaluated to determine impact

)f the double-sided fillet weld

- Original analysis considered one sided el oni

- Additional reinforcement (weld on opposite side) completed and 'impact on stress level Will be

.determined

-or tie rod family, substructure analysis to be

)er.ormed with solid refine. model to more iccurately determine margin.

jAStructural tote grily

Sollid Modeling

~-~

I -

~

Straight Fillet Fillet:Radlus Structural integrity Associates, Inc.

lovides good representation of the vior.

nent modeling can be useful in better behavior of the stress at geometric the steam dryer weld including odifications g can model specific weld geometry nt evaluation will be performed for the a..nel locations of interest eling will be performed for tie rod to havior Strctra Integrity