Results of Ultrasonic Transducer (ULTRA) Irradiation Test

Joshua Daw, Joe Palmer (INL)Pradeep Ramuhalli, Paul Keller, Robert Montgomery (PNNL)Hual-Te Chien (ANL)Bernhard Tittmann, Brian Reinhardt (PSU)Gordon Kohse (MIT)Joy Rempe (Rempe and Associates, LLC (Formerly INL))Jean-Francois Villard (CEA, France)

NSUF User’s WeekJune 22-25, 2015

Goal– Enable in-core use of ultrasonic sensor technologies

for monitoring a wide range of parameters in material and test reactors

Potential for Increased Safety and Improved Performance

• Enhanced accident tolerance• Higher performance (increased

burn rates)• More accurate theoretical

models• In-situ monitoring

BWR Nodular Corrosion

Coolant Effects

PWR Uniform Corrosion

Irradiation Effects

High Burn-up StructureDensification

Sudden Increase in Porosity

Thermal Stress Cracking

Fission Gas Bubbles

Fuel-Cladding ContactFission Product Swelling

Real-time, high resolution/accuracy data provide insights needed to resolve data

Instrumentation is Available in MTRs but Current Sensors have Significant Limitations

Parameter Sensor Comments

Temperature

Melt Wires Peak value, resolution limited by number of wires, Post Irradiation Examination (PIE) required

SiC Monitor Peak value, 100-800 oC temperature range, PIE required

Thermocouples (Types N,K) 1100 oC maximum operating temperature, decalibration due to constituent migration

Thermocouples (Doped Mo/Nb-alloy High Temperature Irradiation Resistant

Thermocouples (HTIR-TC))

1800 oC maximum operating temperature, electrical insulation degradation

Thermocouples (Type C) Decalibration due to transmutation caused by thermal neutron flux

Density/Displacement

Linear Variable Differential Transformer (LVDT)

1-10 mm resolution, qualified to 500 oC

Diameter Gauge 1-10 mm resolution, qualified to 500 oC

Crack Initiation/GrowthDirect Current Potential Drop

(DCPD) MethodSensitive to water chemistry, accuracy limited to ~20%

Young’s Modulus Loaded Creep Specimen LVDT based measurement, accuracy limited to ~10%

Fission Gas Evolution/Pressure

Sampling Multiple isotopes

LVDT Based Pressure gauge 220-1020 psi range, 2.9-7.3 psi accuracy

Ultrasonic Sensors Offer Potential Improvements Over Existing Sensors As Well As New Measurements

• Industrial applications demonstrate ultrasound-based sensors offer unprecedented opportunities for measuring numerous parameters – Temperature (up to 3000 °C) [Some prior use, current development]– Fission gas composition and pressure [In use in France]– Coolant level, flow– Dimensional changes (down to ~1 µm) [Waveguide method in

development]– Microstructure changes (e.g., grain/pore development, crack initiation and

growth, etc.) [PIE fuel porosity measurement in development]– In-service component inspection

PATENTED

Composition detection accurate to 1%

Prior testing of piezoelectrics shows degradation of common materials, but promise for new materials

Barium Titanate

PZT

AlNFast neutrons 1.85X1018 n/cm2

Thermal neutrons 5.8X1018 n/cm2

Gamma dose 26.8 MGy

Thermal cycles to 100 °C ~200

AlN transducer unaffected by

Integrated neutron flux (nvt) (E > 0.1 MeV)

1016 1017 1019

Nor

mal

ized

Pr

1018

1.0

0.8

0.6

0.4

0.2

Thermal depolingHysteresis loopsResonance technique

Integrated neutron flux (nvt) (cm2/sec)

1016 1017

Nor

mal

ized

Pr

1018

1.0

0.8

0.6

0.4

0.2

0.0

Fluence (n/cm2) E > 5 MeV x 1017

0

Am

plitu

de (

V)

6

5

4

3

2

15105

Included Piezoelectric Materials

• Bismuth Titanate

• Aluminum Nitride

• Zinc Oxide

Included Magnetostrictive Materials

• Remendur

• Galfenol

• Arnokrome 4 and 5

(loose)

Magnetostrictive Transducers

Piezoelectric Transducers

Coupling and Signal Interrogation

Magnetostrictive Transducers

Piezoelectric Transducers

Massachusetts Institute of Technology Research Reactor (MITR)

• Licensed for 6 MW operation• Max. in-core volume ~ 46 mm ID x

610 mm long• Neutron Flux (n/cm2-s):

– Thermal: ~3x1013

– Fast: up to 1x1014 (E>0.1 MeV)• Temperature control via He/Ne gas

mix

Test Goals• 18 Month Duration• Total Fluence: ≥1021n/cm2 Fast

MITR

ULtrasonic TRAnsducer (ULTRA) Irradiation Test Capsule Initial Design

• Predicted temperatures exceed some piezoelectric and SPD limitations

Test Capsule

ULtrasonic TRAnsducer (ULTRA) Irradiation Test Capsule Final Design

Test Capsule

Sensors• 2 Type-K TCs• 1 V-SPND• 1 Pt-SPGD• Melt Wire Capsule (5

wires)• Flux Wires

ULTRA Results to Date: BiTiO

• Early irradiation performance shows expected amplitude loss

• Intermittent recovery of signal amplitude– Reasons unclear

• Changes to piezoelectric material?

• Changes to transducer housing/ waveguide?

• Apparent loss of signal at end of test

Test Results

ULTRA Results to Date: AlN• Signal amplitude

erratic but present over course of irradiation

• Coupling and piezoelectric efficiency change as functions of temperature– Signal max.

values increasing slightly

– Signal min. values appear to be noise floor

Test Results

ULTRA Results to Date: ZnO

• Electrical failure experienced during reactor start-up.

• ZnO loses piezoelectricity at temperatures over ~190 oC. Test temperatures are over 400 oC.

• Sporadic signals received during shut-downs indicate piezoelectric properties are maintained.

Test Results

ULTRA Results to Date: Remendur

Test Results

• 12% signal loss during first cycle

• 50% loss at ~1*1021 n/cm2, after increase to full reactor power

• Significant effect of temperature changes observed– Changes to waveform

shape– Recoveries during

SCRAMs

ULTRA Results to Date: Galfenol

Test Results

• 10% signal loss during first reactor cycle

• 25% loss at ~1*1021 n/cm2, after increase to full reactor power

• Some temperature effects evident– Sudden changes to

signal strength during SCRAMs

Conclusions

ULTRA• Both magnetostrictive and piezoelectric transducers

tested• Higher fast fluence reached than prior tests• Highly instrumented

– Real time data to correlate performance• Neutron tolerant candidates of both types identified

– Galfenol, Remendur– AlN

• Enablement of future sensor development