ML051510256

Entergy Vermont Yankee Presentation Meeting Summary Attachment

ML051510256
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	05/09/2005
From:	Entergy Nuclear Operations
To:	Office of Nuclear Reactor Regulation
Boska, J, NRC/NRR/DLPM, 301-415-2901
References
Download: ML051510256 (28)

Text

Entergy VY Power Uprate Project NRR Management Presentation May 9, 2005

Introduction John Dreyfuss - VY Director of Engineering

Agenda Summary of VY EPU Overview of Submittals Steam Dryer Analysis Accident/Transient Codes & Methods Station Blackout Plans Going Forward

Summary - VY EPU December 2001 - Start Project September 2003 - Power Uprate Submittal January 2004 - NRC Acceptance April 2004 - Outage Modifications VYNPS ready for 115% operation

Summary - VY EPU (cont) 28 License Amendment Request Supplements Responses to 161 RAIs No Outstanding Supplements or RAIs

Submittals in Review Steam Dryer Analysis Accident/Transient Codes & Methods Applicability Station Blackout

Main Steam Dryer

Steam Dryer VY Analysis - Overview Industry OE and Lessons Learned VY-specific work:

Acoustic circuit model Benchmark validation Computational fluid dynamics (CFD) model Finite element structural model Proactive strengthening modification Dryer monitoring during power ascension

Steam Dryer FIV Measurement Instrumentation 8 Strain Gages on Main Steam Lines 4 Pressure Transmitters on MS Venturis 31 Accelerometers in Drywell 21 on main steam lines VY Vibration is Very Low

Steam Dryer VY Acoustic Loads Trend 80-100% Power Vermont Yankee PSD Curves Steam Line B PSD Signature VY Measured Data 80%, 90%, 100% Power 0.001 0.011 0.021 0.031 0.041 0.051 0.061 0.071 0.081 0.091 0

5 10 15 20 25 30 Frequenc,y Hz PSIrms^2/Hz Line B 100%

Line B 90%

Line B 80%

Steam Dryer FIV Measurement Comparison Steam Line Data PSD Comparison QC2 (OLTP) vs. VY 100% (CLTP) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

0 20 40 60 80 100 120 140 160 180 200 Frequency, Hz PSIrms^2/Hz VY 100% Pwr Measured Data QC2-OLTP Measured Data

TC TA TD TB QEA(t)

QED(t)

QEC(t)

QEB(t)

CV C CV B CV D CV A QDC(t)

QDD(t)

QDA(t)

QDB(t)

VC VA VD VB SB

'C(t)

'D(t)

'B(t)

'A(t)

N11A N11B Denotes source location Denotes instrument location Steam Dryer Acoustic Analysis Minimal acoustic loads at 80% -

100% power Potential acoustic sources identified for power ascension monitoring

Steam Dryer Acoustic Analysis - VY vs QC Loads 0

0.2 0.4 0.6 0.8 1

1.2 1.4 1.6 0

20 40 60 80 100 120 100% Power QC2: Pre-EPU QC2: EPU RMS Pressure (psid)

Node Number VY

Steam Dryer VY Acoustic Analysis - Benchmark Test Plan & Data Acquisition GE scale model (SMT) 13 test cases Separate from Exelon tests CDI prediction Model of SMT Used only steamline data to predict Entergy results comparison Viable, applied conservatively

Steam Dryer Acoustic Analysis - Benchmark

Vortex shedding produces loads Low magnitude, contribute slightly less than acoustic Steam Dryer Fluid Dynamics Analysis Loads

Steam Dryer Fluid Dynamics Analysis Loads Vermont Yankee CFD Loads, Point on Dryer Face 100% and 120% Power 0.00E+00 5.00E-04 1.00E-03 1.50E-03 2.00E-03 2.50E-03 0

10 20 30 40 50 60 70 80 90 100 Frequency, Hz PSIrms^2/Hz CFD Point L2 100%

CFD Point L2 120%

Steam Dryer VY Analysis - Key FIV Stress Results 385%

484%

469%

1,024%

Margin to Limit

(%)

13,600 13,600 13,600 13,600 Fatigue Stress Limit (psi) 3,535*

1.8 728 1,236 New Cover Plate-Front Hood Gusset Gussets:

2,810 1.8 171 646 Outer Hood Bottom Weld Vertical Plates:

2,900 4.61 92 538 Top Hood 1,328 1.8 46 691 Inner Hood Base Plate Horizontal Plates:

CLTP Peak Stress (psi)

Weld x Stress Concentration Factor Vortex Shedding Max Surface Stress (psi)

Acoustic Max Surface Stress (psi)

• Highest component stress

Steam Dryer VY Strengthening Modification 34° Lifting Lug Indication

License Condition Deliberate, controlled power increase Frequent data collection & evaluation FIV measurements Hourly during power increase & within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> of achieving each 2.5% step Moisture carryover every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Acceptance criteria Level 2: 80% of Level 1 ASME endurance limit Level 1: spectra projected to ASME endurance limit Steam Dryer Power Ascension Monitoring

License Condition (cont.)

Action statements Exceed Level 2: justify further power increase will not exceed Level 1 Exceed Level 1: initiate power reduction to acceptable level within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Steam Dryer Power Ascension Monitoring

Steam Dryer Power Ascension Monitoring 100%

CLTP 105%

CLTP 110%

CLTP 115%

CLTP 120%

CLTP Step 1 Power Ascension Target: 115% CLTP Power Change Monitoring Point Evaluation & Steady State Monitoring Data Start Plateau 1 Step 2 Power Ascension Target: 120% CLTP Plateau 2 Plateau 3 RFO 25 (Oct 2005)

Plateau 4

Steam Dryer Power Ascension Monitoring Vermont Yankee EPU Power Ascension Test Pressure PSD Spectra Limits, Sample Steam Line B 0.000 0.200 0.400 0.600 0.800 1.000 1.200 0

20 40 60 80 100 120 140 160 180 200 Frequency, Hz PSIrms^2/Hz VY Level 1 EPU Limit (<ASME C Endurance Limit)

VY Level 2 Curve (<80% of ASME Endurance Limit)

VY 100% Pwr Measured Data VY 80% Pwr Measured Data VY 120% Pwr Projected Data w/o Resonance

Generic Issue NRC actively reviewing issues in MELLLA+

Large GE EPU operating experience base RAI response demonstrates VY EPU operation is within experience base Codes & Methods Applicability

Engineering Inspection Finding Manning of Alternate AC Source Changed Coping Evaluation & Timeline Results Submitted No Plant Modifications Required Station Blackout

VY EPU Process Going Forward Remaining NRC Activities:

NRR complete draft safety evaluation ACRS review

VY EPU NRC Questions

Entergy VY Power Uprate Project Closing Remarks