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