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High Resolution Neutron Radiography and Tomography of Hydrided Zircaloy-4 Cladding Materials
Available online at www.sciencedirect.com
ScienceDirect Physics Procedia 69 (2015) 478 – 482
10 World Conference on Neutron Radiography 5-10 October 2014
High Resolution Neutron Radiography and Tomography of Hydrided Zircaloy-4 Cladding Materials Tyler Smith, Hassina Bilheux, Holly Ray, Jean-Christophe Bilheux and Yong Yan* Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN-37831, USA
Abstract Hydrogen content and distribution in Zircaloy-4 cladding samples with controlled hydrogen concentrations up to 1100 ppm were studied using neutron radiography and computed tomography. Hydrogen charging was performed in a process tube that was heated to facilitate hydrogen absorption by the metal. A correlation between the hydrogen concentration in the hydrided tubes and the neutron intensity was established, by which hydrogen content can be determined precisely in a small area (55 µm × 55 µm). Image analysis was also performed to evaluate the heating rate and its correlation with the hydrogen distribution through hydrided materials. In addition to image analysis, tomography experiments were performed on Zircaloy-4 tube samples to study the local hydrogen distribution. A 3D reconstruction of the tube was evaluated in which an uneven hydrogen distribution in the circumferential direction can be observed. Published by Elsevier B.V. This is anbyopen accessB.V. article under the CC BY-NC-ND license © 2015 The Authors. Published Elsevier (http://creativecommons.org/licenses/by-nc-nd/4.0/). Selection and peer-review under responsibility of Scherrer Paul Scherrer Selection and peer-review under responsibility of Paul InstitutInstitut. Keywords: Zirconum; hydride; neutron radiography; neutron tomography; hydrogen distribution
* Corresponding author. Tel.: 1-865-5749278; fax: 1-865-5767862 E-mail address: [email protected]
1875-3892 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Selection and peer-review under responsibility of Paul Scherrer Institut doi:10.1016/j.phpro.2015.07.067
Tyler Smith et al. / Physics Procedia 69 (2015) 478 – 482
1. Introduction For zirconium alloy cladding used in commercial light water reactors (LWR), hydrogen pickup increases with the extent of waterside corrosion, thereby causing cladding ductility to decrease (Billone et al., 2008, Bracht et al., 2002, Chervallier et al., 1988, Yan et al., 2013). To better understand fuel behavior, the determination of the hydrogen concentration and distribution is best analysed using a non-destructive evaluation technique. Traditional hydrogen analysis techniques require the zirconium alloy to be destroyed through a vacuum hot extraction (VHE) method. This method of analysis prevents any opportunity for mechanical testing or any further insight into the local distribution of hydrogen within the zirconium alloy to be investigated. It is very advantageous to utilize hydrogen’s large incoherent scattering cross-section because it is significantly larger than the other elements (Zr, Sn, Fe, Cr, Nb…) in commercial zirconium cladding and can easily be seen by neutron imaging methods. This naturally high sensitivity of hydrogen through neutron scattering techniques allows for a detailed, non-destructive study of zirconium cladding. Neutron radiography and scattering have been used to study the hydrogen distribution (Brosse et al., 2006, Lehmann et al., 2004, Yan et al., 2014, Yasuda et al., 2003), by which hydrogen content higher than a few hundred ppm can be quantitatively detected using the property of neutron attenuation due to absorption and scattering from hydrogen. This work shows that neutron radiography and tomography can be used for hydrogen analysis of hydrided Zircaloy-4 cladding samples with a wide range of hydrogen concentrations. The result of non-destructive neutron radiography is compared to direct chemical analysis from VHE along with the hydride density/morphology examined by optical microscopy. Correlations between the neutron image contrast and hydrogen concentrations in hydrided Zircaloy-4 cladding are established. 2. Experimental set-up The material examined for this work was Zircaloy-4 cladding with an outside diameter of 9.5 mm and a wall thickness of 0.57 mm. Hydrogen charging was performed with a hydriding system recently developed at Oak Ridge National Laboratory (ORNL). Direct hydrogen measurements were performed on the hydrided samples using the VHR method (Yan et al., 2013), by which the samples with desired hydrogen concentration were selected for the neutron study. Neutron radiography and tomography experiments were performed at the CG-1D cold neutron beam line of the High Flux Isotope Reactor (HFIR) at ORNL, described in this issue (Santodonato et al., this issue). The neutron wavelength ranges from 0.8 to 6 Å, with a peak at 2.6 Å (Kang et al., 2013). An L/D = 400 collimation was used for the measurements, where L is the distance between the aperture, of diameter D, and the detector. Neutron radiography was performed using a microchannel plate (MCP) detector (Tremsin et al., 2009), while tomographic data were acquired using a charge-coupled device (CCD) equipped with a 50 μm 6LiF/ZnS scintillator. During radiography measurements, the samples were placed approximately 1.5 cm away from the detector, 3 images of each sample were collected, and then were later combined to obtain the mean value image i.e., each pixel was the mean value of the images of a given sample. This operation was done using the custom-made software iMARS (Bilheux et al., this issue). A typical computed tomography set was collected in 18 hours, with a total number of 732 projected images. These projections were reconstructed by a Filtered-Back Projection (FBP) technique that uses a program called Octopus (Vlassenbroeck, 2007). 3. Results and discussion The hydride morphology of the hydrided Zircaloy-4 specimens was examined by optical microscopy, which shows that our hydriding procedure results in uniform distribution of circumferential hydrides across the wall of 17 × 17 Zircaloy-4 cladding (see Fig. 1). The crystal orientation mapping by electron backscatter diffraction (EBSD) reveals that our samples are heavily textured (Yan et al., 2014), which might result in the circumferential hydrides, as shown in Fig. 1. Hydride density increases as the hydrogen concentration in the hydrided Zircaloy-4 sample increases.
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Tyler Smith et al. / Physics Procedia 69 (2015) 478 – 482
Fig. 1 Micrographs of etched surface showing hydride distributions in hydrided Zircaloy-4 specimen; (a) H ≈ 120 ppm and (b) H ≈ 240 ppm
Figure 2a shows the neutron images and their projected intensities of hydrided Zircaloy-4 ring specimens with estimated hydrogen content up to 1100 ppm. The intensity is caused by differences of specimen thickness thus their hydrogen content increases as the path length increases. At each tube specimen position, it produced two peaks corresponding to the boundaries of the tube, in which the neutron beam passes through the largest volume. The neutron reading from the highest peak in the curve is the sum of the scattering from the front and back volume of the tube. The scaled signal from scanning across the tube provides rather precise determination of hydrogen content.
(a)
(b)
Fig. 2 (a) Neutron radiography images of uniformly hydrided Zircaloy-4 rings and horizontal intensity distribution, (b) plot of Zircaloy-4 ring samples neutron intensity vs. hydrogen content.
It was observed that the transmitted neutron intensity decreases proportionally with the hydrogen content. For hydrided Zircaloy-4 specimens examined in this work (hydrogen content İ 1100 ppm), the intensity decrease is linear. The Zircaloy-4 samples examined for neutron scattering were also measured by VHE with approximate hydrogen contents of 193 ppm, 389 ppm, 514 ppm, 1096 ppm, and the hydrogen concentration of as-received sample as ≈ 13 ppm. The neutron transmission readings in Fig. 2a are consistent with those numbers. The best fit algorithm for these experimental points gives the linear function: H = k Nc + C
(1)
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Tyler Smith et al. / Physics Procedia 69 (2015) 478 – 482
where k and C are unknown constants, Nc and H are the normalized neutron counts and extra hydrogen charged to the specimens. We have fitted Eq. (1) with k = 62026 and C = -810, the result of which is shown in Fig. 2b. Evaluations of the local hydrogen distribution in the Zircaloy-4 cladding have been conducted by neutron tomography (nCT). Figure 3a corresponds to the rendered volume obtained from nCT for a 6.25 mm long hydrided tube sample. It clearly shows an uneven hydrogen distribution, possibly due to a gradient in temperature during heating in the tube (in red), which cannot be observed directly by any other techniques. The change in neutron contrast throughout the sample is substantial. In addition, high-temperature (1000°C for 6000s) steam oxidized Zircaloy-4 samples were examined with a MCP detector. The hydrogen analysis on a post-oxidation sample indicates that the hydrogen concentration increases from 13 ppm to > 500 ppm. However, it was not clear how the hydrogen is distributed within the oxidized sample. Fig. 3b is a top-view neutron radiograph of a 1 mm thick oxidized ring sample, which reveals that the hydrogen is mainly distributed within the middle metal layer (the dark region). A line scan across the cladding wall of the oxidized ring confirms the high hydrogen concentration is in this metal layer (see Fig. 3c). In summary, neutron radiography and tomography have been successfully applied for nondestructive quantitative determination of hydrogen content in hydrided Zircaloy-4 cladding. A small amount of hydrogen in zirconium-based commercial LWR fuel cladding can be measured very accurately. The hydrogen concentrations determined using the neutron image methods have been shown to be consistent with the results of chemical analysis (VHE) within experimental uncertainty.
(a)
(b)
(c)
Fig. 3 (a) 3D uneven hydrogen (colored in red) distribution in a hydrided Zircaloy-4 cladding sample, (b) top-view neutron image of oxidized Zircaloy-4 ring sample showing high hydrogen concentrations in the middle, (c) plot of the ring sample’s neutron intensity vs. hydrogen content.
Acknowledgements This research was sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy under Contract No. DEAC05-00OR22725. This research was performed at Oak Ridge National Laboratory's High Flux Isotope Reactor, which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U. S. DOE, which is managed by UT-Battelle, LLC. References J.-C. Bilheux et al., this issue. M. Billone, Y. Yan, T. Burtseva, and R. Daum, “Cladding Embrittlement During Postulated Loss-of-Coolant Accidents,” NUREG/CR-6967, ANL-07/04, (2008).
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Tyler Smith et al. / Physics Procedia 69 (2015) 478 – 482
J. C. Brachet, L. Portier, J. Hivroz, et al., “Influence of Hydrogen Content on the Į/ȕ Phase Transformation Temperature and on the ThermalMechanical Behavior of Zy-4, M4 (ZrSnFeV), and M5™ (ZrNbO) Alloys During the First Phase of LOCA Transient,” Zirconium in the Nuclear Industry, ASTM STP 1423, American Society for Testing and Materials (2002) 673-701. M. Brosse, E. Lehmann, P. Vontobel, and M. Steibrueck, “Quantitative Determination of Absorbed Hydrogen in Oxidized Zircaloy by Means of Neutron Radiography,” Nucl. Instrum. Methods Phys. Res. A 566, (2006) 739-745. J. Chervallier and M. Aucoututier, “Hydrogen in Crystalline Semiconductors,” Annu. Rev. Mater. Sci. 18, (1988) 219. M. Kang, H. Z. Bilheux, S. Voisin, C. L. Cheng, E. Perfect, J. Horita, and J. M. Warren, “Water Calibration Measurements for Neutron Radiography: Application to Water Content Quantification in Porous Media,” Nucl. Instrum. Methods Phys. Res. A 708, (2013) 24-31. E. H. Lehmann, P. Vontobel, and N. Kardjilov, “Hydrogen Distribution Measurements by Neutrons,” Appl. Radiat. Isotopes 61, (2004) 503. L. J. Santodonato et al., this issue. A. S. Tremsin, J. B. McPhate, J. V. Vallerga, O. H. W. Siegmund, J. S. Hull, W. B. Feller, and E. Lehmann, “Detection Efficiency, Spatial and Timing Resolution of Thermal and Cold Neutron Counting MCP Detectors”, Nucl. Instrum. Methods Phys. Res. A 604, (2009) 140-143. J. Vlassenbroeck, M. Dierick, B. Masschaele, V. Cnudde, L. Van Hoorebke, and P. Jacobs, “Software Tools for Quantification of X-ray Microtomography,” Nucl. Instrum. Methods Phys. Res. A 580, (2007) 442-445. Y. Yan, A. S. Blackwell, L. K. Plummer, B. Radhakrishnan, S. B. Gorti, and K. T. Clarno, “Observation and Mechanism of Hydride in Zircaloy-4 and Local Radial Hydride Induced by High Pressure,” 2013 IHLRWM, Albuquerque, New Mexico, April 28 – May 2, 2013. Y. Yan, S. Qian, K. Littrell, C. M. Parish, and L. K. Plummer, “Fast, Quantitative, and Nondestructive Evaluation of Hydrided LWR Fuel Cladding by Small Angle Incoherent Neutron Scattering of Hydrogen,” J. Nucl. Mater. 2014. To be published R. Yasuda, M. Nakada, M. Matsubayashi. K. Harada, Y. Hatakeyama, and H. Amano, “Application of Hydrogen Analysis by Neutron Imaging Plate Method to Zircaloy Cladding Tubes,” J. Nucl. Mater. 320, (2003) 223-230.
ScienceDirect Physics Procedia 69 (2015) 478 – 482
10 World Conference on Neutron Radiography 5-10 October 2014
High Resolution Neutron Radiography and Tomography of Hydrided Zircaloy-4 Cladding Materials Tyler Smith, Hassina Bilheux, Holly Ray, Jean-Christophe Bilheux and Yong Yan* Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN-37831, USA
Abstract Hydrogen content and distribution in Zircaloy-4 cladding samples with controlled hydrogen concentrations up to 1100 ppm were studied using neutron radiography and computed tomography. Hydrogen charging was performed in a process tube that was heated to facilitate hydrogen absorption by the metal. A correlation between the hydrogen concentration in the hydrided tubes and the neutron intensity was established, by which hydrogen content can be determined precisely in a small area (55 µm × 55 µm). Image analysis was also performed to evaluate the heating rate and its correlation with the hydrogen distribution through hydrided materials. In addition to image analysis, tomography experiments were performed on Zircaloy-4 tube samples to study the local hydrogen distribution. A 3D reconstruction of the tube was evaluated in which an uneven hydrogen distribution in the circumferential direction can be observed. Published by Elsevier B.V. This is anbyopen accessB.V. article under the CC BY-NC-ND license © 2015 The Authors. Published Elsevier (http://creativecommons.org/licenses/by-nc-nd/4.0/). Selection and peer-review under responsibility of Scherrer Paul Scherrer Selection and peer-review under responsibility of Paul InstitutInstitut. Keywords: Zirconum; hydride; neutron radiography; neutron tomography; hydrogen distribution
* Corresponding author. Tel.: 1-865-5749278; fax: 1-865-5767862 E-mail address: [email protected]
1875-3892 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Selection and peer-review under responsibility of Paul Scherrer Institut doi:10.1016/j.phpro.2015.07.067
Tyler Smith et al. / Physics Procedia 69 (2015) 478 – 482
1. Introduction For zirconium alloy cladding used in commercial light water reactors (LWR), hydrogen pickup increases with the extent of waterside corrosion, thereby causing cladding ductility to decrease (Billone et al., 2008, Bracht et al., 2002, Chervallier et al., 1988, Yan et al., 2013). To better understand fuel behavior, the determination of the hydrogen concentration and distribution is best analysed using a non-destructive evaluation technique. Traditional hydrogen analysis techniques require the zirconium alloy to be destroyed through a vacuum hot extraction (VHE) method. This method of analysis prevents any opportunity for mechanical testing or any further insight into the local distribution of hydrogen within the zirconium alloy to be investigated. It is very advantageous to utilize hydrogen’s large incoherent scattering cross-section because it is significantly larger than the other elements (Zr, Sn, Fe, Cr, Nb…) in commercial zirconium cladding and can easily be seen by neutron imaging methods. This naturally high sensitivity of hydrogen through neutron scattering techniques allows for a detailed, non-destructive study of zirconium cladding. Neutron radiography and scattering have been used to study the hydrogen distribution (Brosse et al., 2006, Lehmann et al., 2004, Yan et al., 2014, Yasuda et al., 2003), by which hydrogen content higher than a few hundred ppm can be quantitatively detected using the property of neutron attenuation due to absorption and scattering from hydrogen. This work shows that neutron radiography and tomography can be used for hydrogen analysis of hydrided Zircaloy-4 cladding samples with a wide range of hydrogen concentrations. The result of non-destructive neutron radiography is compared to direct chemical analysis from VHE along with the hydride density/morphology examined by optical microscopy. Correlations between the neutron image contrast and hydrogen concentrations in hydrided Zircaloy-4 cladding are established. 2. Experimental set-up The material examined for this work was Zircaloy-4 cladding with an outside diameter of 9.5 mm and a wall thickness of 0.57 mm. Hydrogen charging was performed with a hydriding system recently developed at Oak Ridge National Laboratory (ORNL). Direct hydrogen measurements were performed on the hydrided samples using the VHR method (Yan et al., 2013), by which the samples with desired hydrogen concentration were selected for the neutron study. Neutron radiography and tomography experiments were performed at the CG-1D cold neutron beam line of the High Flux Isotope Reactor (HFIR) at ORNL, described in this issue (Santodonato et al., this issue). The neutron wavelength ranges from 0.8 to 6 Å, with a peak at 2.6 Å (Kang et al., 2013). An L/D = 400 collimation was used for the measurements, where L is the distance between the aperture, of diameter D, and the detector. Neutron radiography was performed using a microchannel plate (MCP) detector (Tremsin et al., 2009), while tomographic data were acquired using a charge-coupled device (CCD) equipped with a 50 μm 6LiF/ZnS scintillator. During radiography measurements, the samples were placed approximately 1.5 cm away from the detector, 3 images of each sample were collected, and then were later combined to obtain the mean value image i.e., each pixel was the mean value of the images of a given sample. This operation was done using the custom-made software iMARS (Bilheux et al., this issue). A typical computed tomography set was collected in 18 hours, with a total number of 732 projected images. These projections were reconstructed by a Filtered-Back Projection (FBP) technique that uses a program called Octopus (Vlassenbroeck, 2007). 3. Results and discussion The hydride morphology of the hydrided Zircaloy-4 specimens was examined by optical microscopy, which shows that our hydriding procedure results in uniform distribution of circumferential hydrides across the wall of 17 × 17 Zircaloy-4 cladding (see Fig. 1). The crystal orientation mapping by electron backscatter diffraction (EBSD) reveals that our samples are heavily textured (Yan et al., 2014), which might result in the circumferential hydrides, as shown in Fig. 1. Hydride density increases as the hydrogen concentration in the hydrided Zircaloy-4 sample increases.
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Tyler Smith et al. / Physics Procedia 69 (2015) 478 – 482
Fig. 1 Micrographs of etched surface showing hydride distributions in hydrided Zircaloy-4 specimen; (a) H ≈ 120 ppm and (b) H ≈ 240 ppm
Figure 2a shows the neutron images and their projected intensities of hydrided Zircaloy-4 ring specimens with estimated hydrogen content up to 1100 ppm. The intensity is caused by differences of specimen thickness thus their hydrogen content increases as the path length increases. At each tube specimen position, it produced two peaks corresponding to the boundaries of the tube, in which the neutron beam passes through the largest volume. The neutron reading from the highest peak in the curve is the sum of the scattering from the front and back volume of the tube. The scaled signal from scanning across the tube provides rather precise determination of hydrogen content.
(a)
(b)
Fig. 2 (a) Neutron radiography images of uniformly hydrided Zircaloy-4 rings and horizontal intensity distribution, (b) plot of Zircaloy-4 ring samples neutron intensity vs. hydrogen content.
It was observed that the transmitted neutron intensity decreases proportionally with the hydrogen content. For hydrided Zircaloy-4 specimens examined in this work (hydrogen content İ 1100 ppm), the intensity decrease is linear. The Zircaloy-4 samples examined for neutron scattering were also measured by VHE with approximate hydrogen contents of 193 ppm, 389 ppm, 514 ppm, 1096 ppm, and the hydrogen concentration of as-received sample as ≈ 13 ppm. The neutron transmission readings in Fig. 2a are consistent with those numbers. The best fit algorithm for these experimental points gives the linear function: H = k Nc + C
(1)
481
Tyler Smith et al. / Physics Procedia 69 (2015) 478 – 482
where k and C are unknown constants, Nc and H are the normalized neutron counts and extra hydrogen charged to the specimens. We have fitted Eq. (1) with k = 62026 and C = -810, the result of which is shown in Fig. 2b. Evaluations of the local hydrogen distribution in the Zircaloy-4 cladding have been conducted by neutron tomography (nCT). Figure 3a corresponds to the rendered volume obtained from nCT for a 6.25 mm long hydrided tube sample. It clearly shows an uneven hydrogen distribution, possibly due to a gradient in temperature during heating in the tube (in red), which cannot be observed directly by any other techniques. The change in neutron contrast throughout the sample is substantial. In addition, high-temperature (1000°C for 6000s) steam oxidized Zircaloy-4 samples were examined with a MCP detector. The hydrogen analysis on a post-oxidation sample indicates that the hydrogen concentration increases from 13 ppm to > 500 ppm. However, it was not clear how the hydrogen is distributed within the oxidized sample. Fig. 3b is a top-view neutron radiograph of a 1 mm thick oxidized ring sample, which reveals that the hydrogen is mainly distributed within the middle metal layer (the dark region). A line scan across the cladding wall of the oxidized ring confirms the high hydrogen concentration is in this metal layer (see Fig. 3c). In summary, neutron radiography and tomography have been successfully applied for nondestructive quantitative determination of hydrogen content in hydrided Zircaloy-4 cladding. A small amount of hydrogen in zirconium-based commercial LWR fuel cladding can be measured very accurately. The hydrogen concentrations determined using the neutron image methods have been shown to be consistent with the results of chemical analysis (VHE) within experimental uncertainty.
(a)
(b)
(c)
Fig. 3 (a) 3D uneven hydrogen (colored in red) distribution in a hydrided Zircaloy-4 cladding sample, (b) top-view neutron image of oxidized Zircaloy-4 ring sample showing high hydrogen concentrations in the middle, (c) plot of the ring sample’s neutron intensity vs. hydrogen content.
Acknowledgements This research was sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy under Contract No. DEAC05-00OR22725. This research was performed at Oak Ridge National Laboratory's High Flux Isotope Reactor, which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U. S. DOE, which is managed by UT-Battelle, LLC. References J.-C. Bilheux et al., this issue. M. Billone, Y. Yan, T. Burtseva, and R. Daum, “Cladding Embrittlement During Postulated Loss-of-Coolant Accidents,” NUREG/CR-6967, ANL-07/04, (2008).
482
Tyler Smith et al. / Physics Procedia 69 (2015) 478 – 482
J. C. Brachet, L. Portier, J. Hivroz, et al., “Influence of Hydrogen Content on the Į/ȕ Phase Transformation Temperature and on the ThermalMechanical Behavior of Zy-4, M4 (ZrSnFeV), and M5™ (ZrNbO) Alloys During the First Phase of LOCA Transient,” Zirconium in the Nuclear Industry, ASTM STP 1423, American Society for Testing and Materials (2002) 673-701. M. Brosse, E. Lehmann, P. Vontobel, and M. Steibrueck, “Quantitative Determination of Absorbed Hydrogen in Oxidized Zircaloy by Means of Neutron Radiography,” Nucl. Instrum. Methods Phys. Res. A 566, (2006) 739-745. J. Chervallier and M. Aucoututier, “Hydrogen in Crystalline Semiconductors,” Annu. Rev. Mater. Sci. 18, (1988) 219. M. Kang, H. Z. Bilheux, S. Voisin, C. L. Cheng, E. Perfect, J. Horita, and J. M. Warren, “Water Calibration Measurements for Neutron Radiography: Application to Water Content Quantification in Porous Media,” Nucl. Instrum. Methods Phys. Res. A 708, (2013) 24-31. E. H. Lehmann, P. Vontobel, and N. Kardjilov, “Hydrogen Distribution Measurements by Neutrons,” Appl. Radiat. Isotopes 61, (2004) 503. L. J. Santodonato et al., this issue. A. S. Tremsin, J. B. McPhate, J. V. Vallerga, O. H. W. Siegmund, J. S. Hull, W. B. Feller, and E. Lehmann, “Detection Efficiency, Spatial and Timing Resolution of Thermal and Cold Neutron Counting MCP Detectors”, Nucl. Instrum. Methods Phys. Res. A 604, (2009) 140-143. J. Vlassenbroeck, M. Dierick, B. Masschaele, V. Cnudde, L. Van Hoorebke, and P. Jacobs, “Software Tools for Quantification of X-ray Microtomography,” Nucl. Instrum. Methods Phys. Res. A 580, (2007) 442-445. Y. Yan, A. S. Blackwell, L. K. Plummer, B. Radhakrishnan, S. B. Gorti, and K. T. Clarno, “Observation and Mechanism of Hydride in Zircaloy-4 and Local Radial Hydride Induced by High Pressure,” 2013 IHLRWM, Albuquerque, New Mexico, April 28 – May 2, 2013. Y. Yan, S. Qian, K. Littrell, C. M. Parish, and L. K. Plummer, “Fast, Quantitative, and Nondestructive Evaluation of Hydrided LWR Fuel Cladding by Small Angle Incoherent Neutron Scattering of Hydrogen,” J. Nucl. Mater. 2014. To be published R. Yasuda, M. Nakada, M. Matsubayashi. K. Harada, Y. Hatakeyama, and H. Amano, “Application of Hydrogen Analysis by Neutron Imaging Plate Method to Zircaloy Cladding Tubes,” J. Nucl. Mater. 320, (2003) 223-230.