Fluid Force Identification A method to Predict Wear of a Control Rod in a Nuclear Power Plant Colloquim by J.W.M. De Jong March 16 2010 01/37

Contents Introduction Research Objective Theory Practice Results Conclusion Contents 02/37

Introduction Increasing demand for Nuclear Power EDF operates 53 Nuclear Power Plants in France alone Presurized Water Reactors vs Boiling Water Reactors New design: European Pressurized Reactor (EPR)‏ Introduction 03/37

Introduction 04/37

Introduction 05/37

Problem The Spider with the Control Rods is extended from the Fuel Rod Assembly when in Operation The Control Rods are Guided by Guide-plates The Fluid Flow Induces a Vibration on the Control Rod The Control Rods Wear out at the Guide-plates Introduction 06/37

Research Objective 'A Method to Model the Fluid Flow and to Predict the Wear of the Control Rods' Method is initiated by Bodel in 2008 My Task: To Verify and Validate this Method Research Objective 07/37

Comparison of Numerical Models Static shapes as Expansion space Mode-shapes in 2D Different Mode-shapes to model system Validation Research Objective 08/37

Theory Modal Analysis Fluid Force Modelling Theory 09/37

Modal Analysis Theory 10/37

Modal Analysis First Mode-shape f1 Frequency w1 = 2 [rad/s] Theory 10/37

Modal Analysis Second Mode-shape f2 Frequency w2 = 4 [rad/s] Theory 10/37

Modal Analysis Third Mode-shape f3 Frequency w3 = 6 [rad/s] Theory 10/37

Modal Analysis Theory 11/37

Modal Analysis Theory 11/37

Modal Analysis Theory 11/37

Modelling the Fluid Force Theory 12/37

Modelling the Fluid Force Theory 12/37

Modelling the Fluid Force Theory 13/37

Modelling the Fluid Force Theory 13/37

Modelling the Fluid Force Theory 13/37

Theory 14/37

Transfer Function Theory 15/37

The Method Model the System in Water using Mode-shapes... ...and use this System to calculate the Point Forces. Theory 16/37

The Study Practice Obtain Experimental Mode-shapes Mass Normalize the Mode-shapes Identify the Fluid Force Practice 17/37

Experimental Modal Analysis Hammer excitation Measure the input and output signal Mass Normalize the Mode-shapes Practice 18/37

The Phacetie Model Modelled guide-plates Practice 19/37

Operational Modal Analysis Strain gauges in-side the tube Measure only the output signal No Normalized Mode-shapes Practice 20/37

The Phacetie Model Practice Modelled guide-plates Water outlet nozzle Water inlet nozzle Practice 21/37

Non-normalised Mode-shapes of the system in Water Mass Normalised Mode-shapes of the system in Air Frequency difference between Water and Air Practice 22/37

The Study Practice Obtain Experimental Mode-shapes Mass Normalize the Mode-shapes Identify the Fluid Force Practice 23/37

Assumptions wair > wwater = Modal mass Mass Normalize the Mode-shapes Practice 24/37

Method I For each mode Practice 25/37

The Study Practice Obtain Experimental Mode-shapes Mass Normalize the Mode-shapes Identify the Fluid Force Practice 26/37

Identifying the Forces Identify the Point Forces by Inverting the Transfer Function using a Pseudo Inverse Practice 27/37

Results Method I Measured and Re-calculated Modelling the system using the Mass normalised Mode-shapes in Water Results 28/37

Results Method I Calculated Point Forces Modelling the system using the Mass normalised Mode-shapes in Water Results 29/37

Different mode-shapes to model system Research Objective 30/37

Modelling the System I Using the Mode-shapes obtained in Water (Mass Normalised)‏ II Using the Mode-shapes obtained in Air (Re-normalised)‏ Practice 31/37

Method I For each mode Practice 32/37

Method II For each mode Practice 33/37

Results Method II Measured and Re-calculated Modelling the system using the re-normalised Mode-shapes in Air Results 34/37

Results Method II Calculated Point Forces Modelling the system using the re-normalised Mode-shapes in Air Results 35/37

Conclusions Use Mass Normalised Mode-shapes in water to describe the System Conclusions 36/37

Questions ? Questions 37/37

Conclusions Experimental Mode-shapes obtained in Air are not Mass Normalised by the Measurement System Transfering Identified Point Forces between different Models will not give the desired Result Fundamental Problem with the Method: The measurment system uses a randomized signal if no input signal is measured. Conclusions 08/37

Extra 08/37

Experimental Modal Analysis Hammer excitation Measure the input and output signal Mass Normalize the Mode-shapes Extra 08/37

Operational Modal Analysis Strain gauges in-side the tube Measure only the output signal No Normalized Mode-shapes Extra 08/37

The Numerical Models The Study 08/37

Extra 08/37

The Study Experimental Numerical The Study 08/37

Assumptions The mode-shapes are the same for the system in water and in air (The Amplitudes of the modeshapes are not the same)‏ There is no added stiffness due to the water surrounding the tube. The added mass due to the water surrounding the tube can be calculated from the frequency difference. The Study 08/37

Experimental Numerical The Study 08/37