Transcript Ojovan
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 n0 • 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 ta 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 17 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 18 Experimental Setup Furnace Pressure Vessel IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008 19 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 22