Acoustic Emission Testing and Analysis Applied
for Materials Used for Immobilisation of
Nuclear Wastes
L.M. Spasova, M.I. Ojovan and F.G.F. Gibb
Immobilisation Science Laboratory,
Department of Engineering Materials,
University of Sheffield
Outline
• AE project at the ISL
• Experimental Setup
• AE signature of corrosion of Al encapsulated in
cementitious structures
• Plans to complete the study
• AE signature of partial melting and
solidification/recrystallisation of natural granite
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
2
At the Beginning
Objective of the Project
FEASIBILITY of AE method to be applied to materials used for
immobilisation of nuclear wastes
OPC
180 days, 20 °C and 95% RH
Al
AE project
at the ISL
Courtesy of Prof Fergus Gibb
V. Belov and A. Aloy, “Using AE in quality control of glass and
ceramics for radioactive waste immobilization”, Mat. Res. Soc.
Symp. Proc., 807, (2004), 163-168
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
3
Non-destructive Testing
and Evaluation
NDT&E Methods
Stress Wave
Ultrasonic
Sonic
Vibration
Acoustic
Emission
Thermographic
Infrared
Thermography
Radiographic
Ultrasonic
and Acoustic
Tomography
Radar
Optic
Visual
Fourier
Laser
Scattering
Electromagnetic
Magnetic
Eddy
Current
Coherent
Amplified
Neutron
X-Ray
Raman
Polarisation
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
Nuclear
Magnetic
Resonance
4
Acoustic Emission
Pre-amplifier
AE Computer-based Instrument
AE Source
AE Wave
PCI-2 AE Data Acquisition Board
AE Sensor
AE Notebook Controller
Pre-amplifier
Duration
Threshold
Pre-trigger
Amplitude
Rise Time
Counts
Counts = 9
Absolute Energy = 87.14 aJ
Experimental Setup
Cement
Sample
Preamplifier
40 dB
Piezoelectric
Transducer
WD → 100 – 1000 kHz
Data Storage,
Visualisation and
Control
Data Acquisition
and Processing
40 dB Threshold level
5 MSPS Sampling Rate
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
6
Corrosion of Al in Cements
Observation
7 d a ys
Sources of AE signals
7 days
7:3 BFS/OPC + Al
O PC + Al
Hydrogen Gas Release
Radial Cracks
Formation and Extension
90 days
4 years
180 days
7:3 BFS/OPC + Al
OPC
Al
OPC
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
7
AE Monitoring
Number of AE Signals
OPC + Al (After mixing)
BFS/OPC +Al (After mixing)
14000
3500
250000
3.00E+008
2.00E+008
8000
1.50E+008
6000
1.00E+008
4000
5.00E+007
2000
0
7:3 BFS/OPC + Al
3000
Cumulative Number of AE Hits
10000
7 days
20
40
60
80
100
120
140
150000
2000
1500
100000
1000
50000
500
0
0.00E+000
0
200000
2500
0
0
160
Cumulative ABS Energy, aJ
2.50E+008
Cumulative ABS Energy, aJ
Cumulative Number of AE Hits
12000
20
40
60
80
100
120
140
160
Time, hrs
Time, hrs
BFS/OPC + Al (180 days)
OPC + Al (90 days)
600000
1800
2500
2.00E+009
1.50E+009
1200
1000
1.00E+009
800
600
5.00E+008
400
2000
400000
1500
300000
1000
200000
500
Cumulative ABS Energy, aJ
1400
Cumulative Number of AE Hits
500000
Cumulative ABS Energy, aJ
Cumulative Number of AE hits
1600
100000
200
0
0.00E+000
0
40
80
120
160
Time, hrs
200
240
280
0
0
20
40
60
80
100
120
140
160
180
0
200
Time, hrs
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
8
AE Signal Characteristics
Amplitude
OPC + Al (After mixing)B
B
BFS/OPC +Al (After mixing)
90 days
100
64
62
90
58
OPC
80
56
Amplitude, dB
Amplitude, dB
60
Al
70
180 days
60
7:3 BFS/OPC + Al
54
52
50
48
46
50
44
42
40
40
0
20
40
60
80
100
120
140
0
160
20
40
60
80
100
120
140
160
Time, hrs
Time, hrs
OPC + Al (90 days)
BFS/OPC + Al (180 days)
B
65
100
60
90
Amplitude, dB
Amplitude, dB
80
70
60
55
50
45
50
40
40
0
40
80
120
160
Time, hrs
200
240
280
0
20
40
60
80
100
120
140
160
180
200
Time, hrs
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
9
AE Signal Characteristics
Primary Frequency
B
BFS/OPC +Al (After mixing)
OPC + Al (After mixing)
500
500
450
450
400
4 years
Primary Frequency, kHz
Primary Frequency, kHz
400
350
300
OPC
250
200
150
100
350
300
250
200
150
100
50
50
0
0
0
20
40
60
80
100
120
140
0
160
OPC + Al (90 days)
40
60
80
100
120
140
160
BFS/OPC + Al (180 days)
B
B
450
180
400
160
350
140
Primary Frequency, kHz
Primary Frequency, kHz
20
Time, hrs
Time, hrs
300
250
200
150
100
50
120
100
80
60
40
20
0
0
0
40
80
120
160
Time, hrs
200
240
280
0
20
40
60
80
100
120
Time, hrs
140
160
180
200
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
10
Signal Processing
• Cross-correlation
where m= 1,2...2N-1
f xy m  
N  m 1

x[ n ] y * [ n  m ]
and N is the number of samples
n0
• Wavelet Transformation
p
1 / 4 

 t   
 
W  a , b  
f



1/ 2
 t 2   2

p
  i  p t 
exp   
 2   

where 
 f t   t dt
is the centre frequency
 is a constant calculated as
1/ 2
    2 / ln 2   5 . 336

*
a ,b
p
 a , b t  

ta
 

b
 b 
1
Suzuki, H., Kinjo, T., Hayashi, Y., Takemoto, M. & Ono, K., Appendix by Hayashi, Y.,
Wavelet Transform of Acoustic Emission Signals, J. Acoustic Emission, 1996, 14(2), 69–84.
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
11
BFS/OPC + Al (180 days)
B
180
160
Primary Frequency, kHz
140
120
100
80
60
40
20
0
0
20
40
60
80
100
120
140
160
180
200
Time, hrs
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
12
BFS/OPC + Al (180 days)
Wavelet Transformation
B
180
160
120
100
Frequency
Primary Frequency, kHz
140
80
60
40
20
0
0
20
40
60
80
100
120
140
160
180
200
Time, hrs
Frequency
Frequency
Time, µs
Time, µs
Time, µs
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
13
OPC + Al (90 days)
B
450
400
300
250
200
150
100
50
0
40
80
120
160
200
240
280
Time, hrs
Frequency
0
Frequency
Primary Frequency, kHz
350
Time, µs
Time, µs
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
14
Crack Initiation and
Propagation
Avnon and D. Yankelevsky, Engineering Fracture Mechanics,
1992, 42(6), 1041-1045
C. Grosse, H. Reinhardt and F. Finck, J. Mater. Civil Engineering, 2003, 15 (3), 274-279
Crack propagation velocity 60 -200
m/s
Crack propagation velocity : Plastic
deformation stress wave velocity = 1:2
to 1:3
Plastic deformation stress wave
velocity = 20% of elastic wave
velocity
Shear elastic wave velocity
concrete 2600 – 2800 m/s
F. A. K. M. Uddin, M. Shigeishi and M. Ohtsu, Meccanica, 2006, 41, 425-442
F. A. K. M. Uddin, K. Numata, J. Shimasaki, M. Shigeishi and M. Ohtsu,
Constr. Build. Mater., 2004, 18, 181-188
in
Plastic deformation wave velocity 520
– 560 m/s
Crack propagation velocity ~173 –
186.6 m/s
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
15
Cracks in Cementitious
Samples
OPC + Al (90 days)
OPC + Al (4 years)
Wavelength

v
f
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008

520
34  10
3
 15 . 29 cm
16
Additional Experiments
• Compression and tensile test of the cementitious
samples
• Background Noise
• Cementitious samples (OPC and 7:3 BFS/OPC)
with encapsulated Mg
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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Melting and Solidification/
Recrystallisation of Granite
Granite Powder
Solid Granite
Before
Granite + 4.64 wt%, at 780 ˚C for 338 hours, 0.15 GPa
After
Crystal
Granite + 2.54 wt%, at 780 ˚C for 334 hours, 0.15 GPa
Glass
Glass
Crystal
Glass
Crystal
Crystal
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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Experimental Setup
Furnace
Pressure
Vessel
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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AE Monitoring
Melting of Granite Samples
Constant temperature (at 780 °C) heating
of granite powder sample
Heating of the solid granite sample
CrAl
PtRh
800
600
600
500
500
400
400
300
300
200
200
100
100
Temperature, C
700
700
500
400
300
200
Temperature, C
700
600
Temperature, C
800
CrAl
PtRd
800
B
C
100
2000
0
0
0
50
100
150
250
300
350
0 8000000
0
400
1200000
50
100
1800
2500
800000
2000
600000
1500
400000
1000
200000
500
200
250
300
350
7000000
1600
6000000
1400
5000000
1200
1000
4000000
800
3000000
600
2000000
400
1000000
200
0
0
0
50
100
150
200
250
300
350
Cumulative ABS Energy, aJ
1000000
3000
150
Time, hrs
Time, hrs
Cumulative ABS Energy, aJ
Cumulative Number of AE hits
3500
200
Cumulative Number of AE hits
4000
0
0
0
50
100
150
200
250
300
350
Time, hrs
Time, hrs
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
20
AE signal Characteristics
Solid Granite
Granite Powder
B
B
800
700
700
Primary Frequency, kHz
Primary Frequency, kHz
600
600
500
400
300
200
500
400
300
200
100
100
0
0
0
50
100
150
200
250
300
350
0
200
Time, hrs
400
600
800
1000
Time, hrs
Experiment with a solid quartz sample to be completed
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
21
Conclusions
AE technique is feasible to continuously monitor the
performance of cement-based materials encapsulating
metallic wastes such as aluminium.
Acknowledgements
National Nuclear Laboratory (BNFL, Nexia Solutions) and
EPSRC for funding
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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