TSP clogging and secondary side deposit – Nechtan LE LOSTEC - 06 January 2014 - p.1 External Publication

AREVA NDE Solutions

AREVA NDE Solutions

TSP clogging and secondaryside deposit: performance evaluation usingsimulation and site resultsNechtan LE LOSTEC , Yann KERNIN, Christian FERRE, Joël MARTENSAREVA NDE-Solutions France,David DUMAY,EDF-CEIDRECannes, October 1st, 2013

TSP clogging and secondary side deposit – Nechtan LE LOSTEC - 06 January 2014 - p.3 External Publication

AREVA NDE Solutions

Summary

Introduction

Secondary side deposit

Clogging of TSP

Conclusion

TSP clogging and secondary side deposit – Nechtan LE LOSTEC - 06 January 2014 - p.4 External Publication

AREVA NDE Solutions

IntroductionSG tubes deposit and TSP clogging

Clogging affects Performance: secondary water flow rate is reduced Safety 1:

• possible secondary water-steam flow instability which inducesstresses on the tubes then risk of fatigue cracking

• excessive stress on tie rods and TSP• stability of water level in secondary• mass of water in the secondary is reduced

Deposit affects Performance: reduces heat transfer Safety: magnetic deposit interacts with eddy current

techniques used to examine the tubes

Secondary side tube deposit Mainly magnetite

Adhering to the wall of the tubes

TSP clogging Mainly magnetite Located on down side of TSP Diaphragm shape

1 H. Bodineau and T. Sollier, “Tube support plate clog ging of french PWR steam generators”, Eurosafe, 2008

Chemical cleaning to remove clogging and deposit materia l

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AREVA NDE Solutions

IntroductionIndustrial solution

Inspections of usual tube examination (bobbin), free s pan deposit evaluationand TSP clogging at the same time

Technical objectives Monitor deposit level and progress speed Provide data to define chemical cleaning parameters Verify chemical cleaning efficiency

Development of a specific combined probe: eddy current (ET) axial sensor to measure free span depo sit and usual tube

examination FLIP sensor to measure TSP clogging

Signal processing and visualization with Aida G3 softw are Automatic analysis

• Signal to clogging/deposit transfer function Graphical representation

• 2D/3D view of clogging/deposit mapping

ET sensor

FLIP sensor

Performance evaluation required, 3 sources of signal s: Mock-up measurements Modeling and simulation Site results

AIDA

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AREVA NDE Solutions

Secondary side depositTechnical approach

Deposit reference tubes manufacturing 1 tube with varying thickness of deposit 1 tube with varying composition (Fe 3O4 mass percentage)

Theoretical formulation of the magnetic permeability o f the deposit Relative permeability µ r as an analytic function of the Fe 3O4 rate

FE simulation, reference tubes measurement versus sim ulation results Model validation Magnetic permeability theoretical formulation validati on

Performance evaluation Identification of influent parameters (geometry and m aterial properties) Parametric study

On-site implementation

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AREVA NDE Solutions

Secondary side depositModel validation

FE modeling using Flux3D

Model validation Cross verification between theoretical formulation,

simulation and experimental results

Deposit thickness effect

050

100

150200250300350

400450500

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Deposit thickness (mm)

Sig

nal a

mp

litu

de (

mV

)

-

Simulation Measurement

Simulation model validation vs experimentalresults (50% magnetite)

Relative permeability analytic formula validation vs correlation modelling/experimental results (0.23mm

deposit)

Calculation of the relative permeability for any depos it composition

SAX probe coilsDeposit

Magnetic permeability effect

0

50

100

150

200

250

300

1 1.02 1.04 1.06 1.08 1.1 1.12

Magnetic relative permeability of the depositS

ign

al a

mpl

itude

(m

V)

-

Measurement Simulation

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AREVA NDE Solutions

Secondary side depositParametric study

Electrical resistivity No influence for ρρρρ > 10-4 ΩΩΩΩ.m

Tube material (Inconel 600 and Inconel 690)

Difference of 1.3% in amplitude and 2.2° in phase

Limitation of the number of reference tubes

Deposit configuration 23% under estimate of deposit thickness for

0.67mm thickness when 180° deposit instead of 360° deposit

Deposit density and composition Variation of the deposit relative permeability from

1.37 to 1.41 for Fe 3O4 mass percentage from 88% to 95%

Copper Important effect on the signal

Necessity to manufacture reference tube withrepresentative composition

0

0.000005

0.00001

0.000015

0.00002

0.000025

0 0.001 0.002 0.003 0.004 0.005

Electrical resistivity of the deposit material (Ω.m)

Sig

nal

am

plit

ud

e (a

rbitr

ary

un

its)

-

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Deposit thickness (mm)

Sig

na

l am

plit

ud

e (

mV

) - Inconel 600

Inconel 690

050

100150

200250300

350400

450500

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Mean deposit thickness (mm)

Sig

nal

am

plitu

de

(mV

)

-

180° 360°

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AREVA NDE Solutions

500kg (±40%)

SG 3

1000kg (±30%)1250kgEDF

reference

AREVA Depositmapping

SG 2SG 1

Secondary side depositOn-site implementation

Since 2009, 3 SG secondary side deposit analysis 3/4" and 7/8" tubes

25% or 50% of the tube bundle

Three more steam generators to be inspected

Results

Good correlation between AREVA deposit mappingand EDF reference (mass balance method)

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AREVA NDE Solutions

Performance evaluation using finite element simulation Step 1: validation of SAX and FLIP models

• EDF Clogging mock-ups: 0 - 25 - 50 - 75 -100% clogging rate• Finite element simulation• Simulated versus experimental signals

Step 2: use models to determine influent parameters of real deposit/clogging configuration

• Real deposit/clogging configuration parameters• Finite element simulation with variable parameters, determining influent parameters• Comparison to site measurements to find correct parameters value

Step 3: predict signal from specific deposit/clogging co nfiguration

Conclusion on FLIP and SAX probe performances

TSP cloggingTechnical approach

FLIP signal

SAX signal

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AREVA NDE Solutions

TSP cloggingFLIP model validation

Mock-up model from CAD Limited plate radius

4 volumes for the different clogging rates

Mock-up model for FE simulation No tube because no effect on probe signal

1/8 geometry + symmetry/periodic conditions

Unknown material properties TSP magnetic permeability

Clogging material magnetic permeability

2D parametric study fo validation / material properties identification

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AREVA NDE Solutions

Measured and simulated probe signals

Good agreement but …

… multiple ‘visible’ solutions…

… anyway model is validated.

Transfer function for operational use:

TSP cloggingFLIP model validation

Best objective solution:

But depends on material properties

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Conclusion

Operational solution for tube deposit and TSP cloggin g withpositive results

Deposit and clogging probes performance study in progr ess FE modeling vs mock-up Validation of FE models Determination of influent parameters Fine tuning of transfer functions

Perspective: comparison with real site deposit/cloggi ng mass measurements from Sherlock program

Update transfer functions used for deposit/clogging map ping in AIDA software

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