ML080360067

Steam Dryer RAI 15 Status, Slides

ML080360067
Person / Time
Site:	Browns Ferry
Issue date:	01/25/2008
From:	Tennessee Valley Authority
To:	Office of Nuclear Reactor Regulation
Brown Eva, NRR/DORL, 415-2315
Shared Package
ml080360097	List: ML080360067
References
TAC MD5262, TAC MD5263, TAC MD5264
Download: ML080360067 (15)

Text

im TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT Steam Dryer RAI 15 Status January 25, 2008.rl""",

Finite Element Model Discrepancies"Differences Between Unit 1 FEM and Actual Configuration

-Cover Plate is 1 " thick vs. 1/2/" thick as modeled-Cover plate has no man-way as modeled-Outer hood vertical stiffeners have top covers that were omitted in model-Dryer support restraint was modeled as bolted restraint

-now revised to pin connection

-Support beam was disconnected from support ring (due to cracked welds) vs. modeled as attached to support ring" FEM Verified G. Nelson2 I 0.00 10 .00 (in) 5 .010.00 (n/ Increase cover plate thickness to 1" Analyze with a 3/4" Fillet weld Remove Man way Revise Dryer support restraint Add top covers to vertical stiffeners Browns Ferry Unit 1 Finite Element Model Finite Element Model Discrepancies

• Differences Between Unit 2/3 FEM and Actual Configuration

-The cover plate attachment welds to support ring and hood were not described as undersized welds in stress analysis-The man-way attachment welds were not described as undersized welds in stress analysis-The cover plate was not modeled with a 2" rise to the hood attachment

• Modifications to Unit 2 Steam Dryer in 2009-Replace and upgrade dryer tie bar design-Reinforce cover plate and man-way welds* Modifications to Unit 3 Steam Dryer in 2010-Replace and upgrade dryer tie bar design-Reinforce cover plate and man-way welds* FEM Verified G. Nelson 4 I 0.00 100.00 (in) 0.00 100.00 (in)/ 50.00 50.00" Clarify that Cover Plate & Man-way welds to be reinforced from '" to 3/8"" Cover plate slopes up 2" from support ring, was modeled as flat" Revise Dryer Support Restraint from fixed to pinned Browns Ferry Unit 2, 3 Finite Element Model 5 Potential for SRV Resonance 0 Potential for Resonance Onset Between CLTP and EPU-Frequency range 105 Hz to 112 Hz most likely-No demonstrated SRV resonance at CLTP velocities (135 -142.25 ft/sec) from plant data* 1/5 Scale Testing of A & B Main Steam Lines (preliminary data)-A MSL has 3 SRVs and 4 Blind Flanges-B MSL has 2 SRVs in active steam flow region, and 2 SRVs and 2 Blind Flanges in dead leg-1/5 Scale Test Report to be completed on 1/30/2008-Testing shows SRV frequency (109 Hz) onset starting at CLTP and small increase at EPU Mach numbers-Need to quantify SRV resonance through further testing J. Wolcott 6 Potential for SRV Resonance 1/8 Scale Testing for EPU Prediction

-Assess Stress Margins at EPU o Quantify the effects of potential resonance o Used to judge adequacy of CLTP stress margin o Used to determine the need for mitigation modifications

-Test circuit includes reactor vessel, dryer, nozzles, 4 MSLs and components through turbine high pressure inlet o Provides flow interaction and potential coupling between steam lines o Comparison of CLTP and EPU flows provides "Bump up" factor for steam dryer stress margin at EPU conditions

-BUMP UP Factor Applied to CLTP Results J. Wolcott 7 Bias and Uncertainty Issues RA" FEM Inputs Still Under NRC Review-Hope Creek 2 Dryer Benchmark Analysis (shake test)-Mesh Convergence

-Frequency Discretization Errors-75% Bias and Uncertainty Applied to the Peak-Other -NRC discuss" Issue Resolution Impacts BFN FEM Results and Schedule K. Spates 8 Margin Improvement IVA* Noise Reduction and Margin Improvement

-FIV noise floor o Remove strain gage signals associated with minimal steam flow o 1000# data available for Unit 1 o 0# data available for Unit 2 0 1000# data will be taken for Unit 3-Will be incorporated in revised stress analyses J. Wolcott 9 Clarification of RAIs" RAI 15 Questions 139/106 & 145/112* Follow-up Discussion from NRC/TVA Meeting 12/10/07-Question, cannot be answered as written-FEM Outputs in terms of displacement are not available* Alternative Responses-Discussion A. Bilanin 10 Schedule for RAI 1 5 Responses IRA* Project Schedule Impacts-Resolution of Bias and Uncertainty Issues-Performance of Scale Model Tests-Collection of Unit 3 Data-Re-perform FEM Analyses F.E. Hartwig 11 Preliminary Data 1/5 Scale Testing rns Ferrv MST A Browns Ferry MSL A with Inserts Bro 25 EI-20 15 10 5 0 0.05 BF1-- BF2-4-BF3-- BF4.........

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0.7 0 .5 -- IF 2 I ..... .---- ---- .. .------ ...S06 -0 PIFi-- ------0 .4 0 .. .. .. .----. 7 -- 00..2 CLTP- ----------0.15 0.2 0.25 0.- 0.05 0.1 0-15 0.2 Mach Number Mach Number CLTP M = 0.087, EPU M = 0.1 Significant effect seen from BF Inserts at the BF Chamber lfT t P1-4T Referonc*4 to CLTP------------

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0.1 0.25 0.3 I BF -1448 Hz Test 353 Hz Plant 10#W 10 -S10" 10ýS10410 -10'IV, 10, Frmquency.

M-FrequeM. If Preliminary Data 1/5 Scale Testing Browns Ferry MSL B Browns Ferry MSL B 8 7 N 0 z V)6 5 4 3 2 1 0 0.-------- I ---------

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.---. .V 0 i -SRV2-... SRV3 0 RV E PU--- -- --- --- -- ---- ----- -- --- --- --- --- --CLTP ---------

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0--- .... .....-- ---------

-- ---- ---z C-1 1.2 1 0.8 0.6 0.4 BF1 BF2 END EPU------- ----------

CLTP ----- -- ----------

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11 --------- ---- -----0.2 0 0.05 0.1 0.15 0.2 0.25 Mach Number 0.3 0..05 0.1 0.15 0.2 0.25 Mach Number 0.3 0.35 MSL B Has SRV 1, 2 in Steam Flow, SRV 3, 4 in Dead Leg EPU 10, 10, All Blind Flanges in Dead Leg (w/o Inserts)to0 Io'10o*1 0 IO .. .....A IE;01491COR~f16~dSOCXTP EPU I i I I lO~1e FrmquwCxy.

W Preliminary Data 1/5 Scale Testing 101 fN91-6 Rerned to CUP bf-491-0 Refeoemed to CLTP I- 1 R reET10,.SRV -450 Hz Test to ~109 HzPlant C...... .... ..............

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BF.- 900 HzTest~.l4 .. .~.. ..218 Hz Plant..1.. ......... ....p10 ~ ~~~~~....

... .. ..----IC Preliminary Data 1/5 Scale Testing Browns Ferry MSL A Browns Ferry MSL A with Inserts 12 N z I-10 8 6 4 2---------

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--- I-- ----S V I IV C)I-C)I...12 10 8 6 4 2 I 0.0 A ý , I ..I ...ý .I ý ..5 0 t 0.05 0.1 0.15 0.2 Mach Number 0.25 0.3 0.1 0.15 0.2 0.25 Mach Numnber 0.3 E z CLTP M = 0.087, EPU M = 0.1 EPU EPU br-'491-15 Referenced t0 CLTP bFf49147 Referemcedto CUTP SRV2 I SRV3 SRV -450 Hz Test 10' 'BF- 900 Hz Test:~~~~~~ 218 Hz Plant ° " .... -10.... ... -10' 10Frequency.

1z Frequency, M No significant effect seen on SRVs from Blind Flange Inserts