Suzuki, Kiichi; Kato, Masato; Sunaoshi, Takeo*; Uno, Hiroki*; Carvajal-Nunez, U.*; Nelson, A. T.*; McClellan, K. J.*
Journal of the American Ceramic Society, 102(4), p.1994 - 2008, 2019/04
The fundamental properties of CeO were assessed using a range of experimental techniques. The oxygen potential of CeO was measured by the thermogravimetric technique, and a numerical fit for the oxygen potential of CeO is derived based on defect chemistry. Mechanical properties of CeO were obtained using sound velocity measurement, resonant ultrasound spectroscopy and nanoindentation. The obtained mechanical properties of CeO are then used to evaluate the Debye temperature and Gruneisen constant. The heat capacity and thermal conductivity of CeO were also calculated using the Debye temperature and the Gruneisen constant. Finally, the thermal conductivity was calculated based upon laser flash analysis measurements. This result demonstrates that the thermal conductivity has strong dependence upon material purity.
Dioguardi, A. P.*; Yasuoka, Hiroshi*; Thomas, S. M.*; Sakai, Hironori; Cary, S. K.*; Kozimor, S. A.*; Albrecht-Schmitt, T. E.*; Choi, H. C.*; Zhu, J.-X.*; Thompson, J. D.*; et al.
Physical Review B, 99(3), p.035104_1 - 035104_6, 2019/01
We present a detailed nuclear magnetic resonance (NMR) study of Pu in bulk and powdered single-crystal plutonium tetraboride (PuB), which has recently been investigated as a potential correlated topological insulator. The Pu NMR spectra are consistent with axial symmetry of the shift tensor showing for the first time that Pu NMR can be observed in an anisotropic environment and up to room temperature. The temperature dependence of the Pu shift, combined with a relatively long spin-lattice relaxation time (), indicate that PuB adopts a nonmagnetic state with gaplike behavior consistent with our density functional theory calculations. The temperature dependencies of the NMR Knight shift and imply bulk gaplike behavior confirming that PuB is a good candidate topological insulator.
Sekine, Megumi; Matsuki, Takuya; Suzuki, Satoshi*; Tsutagi, Koichi; Tomikawa, Hirofumi; Nakamura, Hironobu; LaFleur, A.*; Browne, M.*
Proceeding IAEA Symposium on International Safeguards; Building Future Safeguards Capabilities (Internet), 8 Pages, 2018/11
The IAEA has proposed, in its Research and Development plan (STR-385), the development of technology to enable real-time flow measurement of nuclear material as part of an advanced approach to effective and efficient safeguards for reprocessing facilities. To address this, JAEA and JNFL had previously designed and developed a neutron coincidence based non-destructive assay system to monitor Pu in solution directly after a purification process. To enhance this technology for entire reprocessing facilities, as a feasibility study, JAEA has been tackling development of a new detector to enable monitoring of Pu in solutions with numerous fission products (FPs) as a joint research program with the U.S. DOE. In this study, the High Active Liquid Waste (HALW) Storage Facility in Tokai Reprocessing Plant (TRP) was used as the test bed. The design information of the HALW storage tank and radiation (type and intensity) were investigated, to develop a Monte Carlo N-Particle Transport Code (MCNP) model. Then, dose rate distribution inside the concrete cell where the HALW tank is located was measured, to enable design of new detectors and check the integrity of the MCNP model and its applicability. Using the newly-designed detectors, -rays and neutrons could be measured continuously at the outside/inside of the concrete cell, to optimize detector position and the radiation characteristics. The applicability as a Pu-monitoring technology was evaluated, based on the simulation results and -ray/neutron measurement results. We have found that there is a possibility to monitor the change of Pu amount in solution by combination of -ray and neutron measurements. The results of this study suggest a feasibility study into the applicability and capability of Pu monitoring to enhance the entire reprocessing facility handling Pu with FPs. In this paper, a summary of the project will be presented.
Chadwick, M. B.*; Capote, R.*; Trkov, A.*; Herman, M. W.*; Brown, D. A.*; Hale, G. M.*; Kahler, A. C.*; Talou, P.*; Plompen, A. J.*; Schillebeeckx, P.*; et al.
Nuclear Data Sheets, 148, p.189 - 213, 2018/02
The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear facilities - U, U, Pu, Fe, O and H - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality. This report summarizes our results and outlines plans for the next phase of this collaboration.
Fukushima, Masahiro; Goda, J.*; Bounds, J.*; Cutler, T.*; Grove, T.*; Hutchinson, J.*; James, M.*; McKenzie, G.*; Sanchez, R.*; Oizumi, Akito; et al.
Nuclear Science and Engineering, 189, p.93 - 99, 2018/01
To validate lead (Pb) nuclear cross sections, a series of integral experiments to measure lead void reactivity worths was conducted in a high-enriched uranium (HEU)/Pb system and a low enriched uranium (LEU)/Pb system using the Comet Critical Assembly at NCERC. The critical experiments were designed to provide complementary data sets having different sensitivities to scattering cross sections of lead. The larger amount of the U present in the LEU/Pb core increases the neutron importance above 1 MeV compared with the HEU/Pb core. Since removal of lead from the core shifts the neutron spectrum to the higher energy region, positive lead void reactivity worths were observed in the LEU/Pb core while negative values were observed in the HEU/Pb core. Experimental analyses for the lead void reactivity worths were performed with the Monte Carlo calculation code MCNP6.1 together with nuclear data libraries, JENDL 4.0 and ENDF/B VII.1. The calculation values were found to overestimate the experimental ones for the HEU/Pb core while being consistent for the LEU/Pb core.
Swinhoe, M. T.*; Menlove, H. O.*; Marlow, J. B.*; Makino, Risa; Nakamura, Hironobu
LA-UR-17-23474, 28 Pages, 2017/04
The Inventory Verification Sample system (INVS) has been used for IAEA verification measurement at the Plutonium Conversion Development Facility for MOX powder and Pu solution samples (measurement uncertainty: about 3-5%). If the measurement uncertainty can be improved (to 1%), it is expected that the range of usage can be extended and it could reduce the number of destructive analyses. In order to improve the measurement uncertainty for solution samples, we conducted three different types of calibration method that are passive calibration curve method, known- method and multiplicity method after optimization of detector parameter and sample position. In the range of concentration of typical solution samples, a good correlation was found between measured doubles and Pu effective mass in the three methods. Especially, the result of the conventional calibration curve method and known- method met our target uncertainty within 1% (22 hours measurement). Since it is thought that background singles change may affect measurement uncertainty, an additional shielding was installed around the INVS to reduce those effects. This shielding improved measurement uncertainty in known- method. The results with this shielding suggests passive calibration method and known- method could achieve the target uncertainty within 1% less than 1 hour measurement time.
Nakamura, Hironobu; Nakamichi, Hideo; Mukai, Yasunobu; Hosoma, Takashi; Kurita, Tsutomu; LaFleur, A. M.*
Proceedings of International Conference on Mathematics & Computational Methods Applied to Nuclear Science & Engineering (M&C 2017) (USB Flash Drive), 7 Pages, 2017/04
In order to maintain facility nuclear material accountancy (NMA) and safeguards properly, to understand where and how much holdup deposit in the process is presence is very important for the cleanout before PIT. JAEA and LANL developed a GloveBox Cleanout Assistance Tool (BCAT) to help cleanout (MOX powder recovering in a glovebox) for invisible holdup effectively by computational approach which is called distributed source-term approach (DSTA). The BCAT tool is a simple neutron measurement slab detectors and helps operator to find locations of holdup. To know the holdup location and the activity from the neutron measurements, the relation between BCAT measurements results at predetermined positions (57 positions) and source voxels (53 voxels) that we want to know the holdup activity was mathematically defined as a matrix by the MCNPX simulation. The model of MCNPX for entire process is very precisely established. We have implemented and experimentally proved that the BCAT tool can direct the operator to recoverable holdup that would otherwise be accounted for as MUF. Reducing facility MUF results in a direct improvement of the facility NMA. The BCAT enables the staff to significantly improve their knowledge of the locations of residual holdup in the process area. JAEA would like to use this application for dismantling of the glovebox with transparency in the future.
Tanigawa, Masafumi; Mukai, Yasunobu; Nakamura, Hironobu; Kurita, Tsutomu; Henzlova, D.*; Menlove, H. O.*
Dai-37-Kai Kaku Busshitsu Kanri Gakkai Nippon Shibu Nenji Taikai Rombunshu (CD-ROM), 9 Pages, 2017/02
no abstracts in English
Sekine, Megumi; Matsuki, Takuya; Suzuki, Satoshi; Tanigawa, Masafumi; Yasuda, Takeshi; Yamanaka, Atsushi; Tsutagi, Koichi; Nakamura, Hironobu; Tomikawa, Hirofumi; LaFleur, A. M.*; et al.
EUR-28795-EN (Internet), p.788 - 796, 2017/00
The IAEA has proposed in its long-term R&D plan, the development of technology to enable real-time flow measurement of nuclear material as a part of an advanced approach to effective and efficient safeguards for reprocessing facilities. To address this, JAEA has designed and developed a neutron coincidence based nondestructive assay system to monitor Pu directly in solutions which is after purification process and contains very little fission products (FPs). A new detector to enable monitoring of Pu in solutions with numerous FPs is being developed as a joint research program with U.S. DOE at the High Active Liquid Waste (HALW) Storage Facility in Tokai Reprocessing Plant. As the first step, the design information of HALW tank was investigated and samples of HALW was taken and analyzed for Pu concentration and isotope composition, density, content of dominant nuclides emitting ray or neutron, etc. in order to develop a Monte Carlo N-Particle Transport Code (MCNP) of the HALW tank. In addition, ray source spectra simulated by Particle and Heavy Ion Transport code System (PHITS) was developed by extracting peaks from the analysis data with germanium detector. These outputs are used for the fundamental data in the MCNP model which is then used to evaluate the type of detector, shielding design and measurement positions. In order to evaluate available radiations to measure outside the cell wall, continuous ray and neutron measurement were carried out and the results were compared to the simulation results. The measurement results showed that there are no FP peaks above 3 MeV. This paper presents an overview of the research plan, characteristics of HALW, development of source term for MCNP, simulation of radiation dose from the HALW tank and radiation measurement results at outside of cell wall.
Henzlova, D.*; Menlove, H. O.*; Tanigawa, Masafumi; Mukai, Yasunobu; Nakamura, Hironobu
EUR-28795-EN (Internet), p.313 - 323, 2017/00
Facing the depletion of He gas supply and the continuing uncertainty of options for future resupply, Los Alamos National Laboratory (LANL) designed and built a He free full scale thermal neutron coincidence counter based on boron-lined parallel-plate proportional technology. The counter was designed as a direct alternative to High Level Neutron Coincidence counter (HLNC-II). This paper provides a summary of performance evaluation of HLNB under realistic field conditions at Plutonium Conversion Development Facility (PCDF) of Japan Atomic Energy Agency (JAEA). The field test included a range of small to large mass MOX materials that represent realistic process samples and provided key insight on and validation of the feasibility of HLNB as a safeguards instrument in realistic facility environment. In particular, the results of verification measurements demonstrate that HLNB is capable to satisfy ITV expected for HLNC-II-type counter of 2.1% in 300s measurement time.
Gaffney, A.*; Hubert, A.*; Kinman, W. S.*; Magara, Masaaki; Okubo, Ayako; Pointurier, F.*; Schorzman, K. C.*; Steiner, R. E.*; Williams, R. W.*
Journal of Radioanalytical and Nuclear Chemistry, 307(3), p.2055 - 2060, 2016/03
In and inter-laboratory measurement comparison study, four laboratories (LLNL, LANL, CEA, JAEA) determined Th-U model ages of uranium certified reference material NBL U050 using isotope dilution mass spectrometry. The model dates determined by the participating laboratories range from 9 March 1956 to 19 October 1957, and are indistinguishable given the associated measurement uncertainties. These model ages are concordant with to slightly older than the known production age of NBL U050, indicating unsufficient purification of U050.
Kato, Masato; Ikusawa, Yoshihisa; Sunaoshi, Takeo*; Nelson, A. T.*; McClellan, K. J.*
Journal of Nuclear Materials, 469, p.223 - 227, 2016/02
Thermal expansion of (UPu)O (x = 0, 0.01, 0.02, 0.03) and (UPu)O was measured with a dilatometer in an oxygen partial pressure-controlled atmosphere. The oxygen partial pressure was controlled to hold a constant oxygen-to-metal ratio in the (U,Pu)O during the measurement. Thermal expansion slightly increased with the decrease in oxygen-to-metal ratio. The relationship was derived to describe thermal expansion.
Nakamichi, Shinya; Hirooka, Shun; Sunaoshi, Takeo*; Kato, Masato; Nelson, A.*; McClellan, K.*
Transactions of the American Nuclear Society, 113(1), p.617 - 618, 2015/10
Cerium dioxide has been used as a surrogate material for plutonium dioxide. Dorr et al reported the use of hyper-stoichiometric conditions causes the start of shrinkage of (U,Ce)O at low temperature compared with the sintering in reducing atmosphere. However, the precise stoichiometry of the samples investigated was not controlled or otherwise monitored, preventing any quantitative conclusions regarding the similarities or differences between (U,Ce)O and (U,Pu)O. The motivation for the present work is therefore to compare the sintering behavior of MOX and the (U,Ce)O MOX surrogates under controlled atmospheres to assess the role of oxygen defects on densification in both systems.
LaFleur, A. M.*; Nakamura, Hironobu; Menlove, H. O.*; Mukai, Yasunobu; Swinhoe, M. T.*; Marlow, J. B.*; Kurita, Tsutomu
Proceedings of 37th ESARDA Annual Meeting (Internet), p.435 - 441, 2015/08
The IBAS (Improved Holdup Blender Assay System) system for safeguards and nuclear material accountancy (NMA) of holdup measurements is used at PCDF. The purpose of this detector is to measure the doubles rate from each glovebox in order to determine the mass of Pu holdup. In order to establish calibration curves for the IBAS detector and improve the holdup measurement methodology, JAEA conducted the IBAS calibration exercise with LANL support using MOX standards in 2010. In 2011, a cleanout exercise was performed and the results showed that the holdup removed from the glovebox had a significantly higher alpha term (alpha = 15.8 - 31.5) than the MOX standards (alpha = 0.67) used to establish the 2010 calibration curves. To further investigate these findings, JAEA conducted slope validation measurements in 2013 to confirm the validity of IBAS calibration slopes for the case of high alpha holdup. This paper describes the IBAS slope validation tests, analysis of the experimental results, and the evaluation of the need for a correction factor for the high alpha holdup. Quantifying the alpha term of the holdup in each glove box and understanding how this value changes over time is important to improving the overall NMA at PCDF. The results from this work will provide invaluable experimental data that directly supports safeguards and NMA measurements of plutonium holdup in gloveboxes.
Nakamura, Hironobu; Mukai, Yasunobu; Kurita, Tsutomu
Book of Abstracts, Presentations and Papers of Symposium on International Safeguards; Linking Strategy, Implementation and People (Internet), 8 Pages, 2015/03
The Distributed Source-Term Analysis (DSTA) technique has been used in a variety of safeguards applications to determine location and quantity of material contained within large sample volumes. By applying this method, JAEA developed and applied two different neutron measurement techniques in order to improve own MC&A. The first advanced technique is a Glove Box Cleanout Assistance Tool (BCAT). It is used by operator during cleanout just before PIT to increase recovered material, to decrease unmeasured inventory, and to perform the cleanout activity effectively. The BCAT is being introduced to the actual cleanout since 2011. The second advanced technique is a dynamic cross-talk correction (DCTC) method. The DCTC can obtain actual doubles signal cross-talk between multiple gloveboxes. In order to assay Pu amount in the holdup correctly, we implemented an improved HBAS system using DCTC. Two advanced holdup measurement technologies provide appropriate safety and safeguards environment to conduct nuclear cycle with operator and inspector.
Makino, Risa; Swinhoe, M. T.*; Suzuki, Hisanori; Ikeda, Atsushi*; Menlove, H. O.*; Shimizu, Yasuyuki; Nakamura, Hironobu
Kaku Busshitsu Kanri Gakkai (INMM) Nippon Shibu Dai-35-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/01
The Inventory Verification Sample system (INVS) is a non-destructive assay system for samples to quantify the Pu amount in Pu nitrate solutions and MOX with 31.3% of counting efficiency. It has been used for IAEA verification measurement for many years at the Plutonium Conversion Development Facility for the samples taken at the timing of PIV etc. as a partial defects verification system (uncertainty: about 3-5%). If the measurement uncertainty can be improved (to 1%), it is expected that the usage can be extended to the operator's own measurements in MC&A to reduce the number of destructive analyses. In order to improve the measurement uncertainty for solution samples, after optimization of detector parameter and sample position, we conducted 3 different types of calibration method that is passive calibration curve, known- and multiplicity method to achieve the target uncertainty. To perform calibration and control the measurement quality, MOX fuel pellets with known Pu amount are fabricated and used. In the range of concentration of typical solution samples, we could confirm good correlations between measured doubles and Pu effective mass in the three methods. Especially, it was confirmed that the conventional calibration curve method could meet our target uncertainty (1%).
Nelson, A. T.*; Rittman, D. R.*; White, J. T.*; Dunwoody, J. T.*; Kato, Masato; McClellan, K. J.*
Journal of the American Ceramic Society, 97(11), p.3652 - 3659, 2014/11
Mukai, Yasunobu; LaFleur, A. M.*; Nakamura, Hironobu; Menlove, H. O.*; Swinhoe, M. T.*; Marlow, J. B.*; Kurita, Tsutomu
Proceedings of INMM 55th Annual Meeting (Internet), 8 Pages, 2014/07
In order to improve the safeguards and nuclear material accountancy of holdup measurements and establish an alternative technology for He shortage, we have designed the B + He Integrated Continuous Monitor (BHCM) and implemented the measurements to continuously monitor the holup in gloveboxes at Plutonium Conversion Developoment Facility. In this paper, we present the outline of BHCM, the comparison between MCNP simulations and the measured results in preliminaly test and a demonstration of process monitoring ability during operation to see the relation between Totals trend and operational status by using B detection tubes.
Makino, Risa; Swinhoe, M. T.*; Suzuki, Yoshimasa; Mukai, Yasunobu; Menlove, H. O.*; Marlow, J. B.*; Nakamura, Hironobu
Proceedings of INMM 55th Annual Meeting (Internet), 9 Pages, 2014/07
The Inventory Verification Sample systems (INVS) is a non-destructive assay (NDA) system for small inventory samples to quantify the Pu amount in Pu and U-Pu nitrate solutions and MOX powder with 31.3% counting efficiency (for Cf). It has been used for IAEA safeguards measurement for many years at the Plutonium Conversion Development Facility (PCDF) for the samples taken at the time of Random Interim Inspection (RII) and Physical Inventory Verification (PIV), and is currently used as partial defects verification equipment with uncertainty about 35% accuracy for solution samples. The INVS is a inline detector therefore it is very convenient to use since it can be used for a sample inside the glove box without bag-out. If the measurement uncertainty can be improved (to 1%), it is expected that the usage can be extended to the operator's own measurements in MC&A to reduce effort and the number of destructive analyses (DA). In order to improve the measurement uncertainty, we have performed multiplicity measurements using a variety of solution samples (concentration, acidity and volume) to determine the Pu amount and uncertainty, although the multiplicity analysis is challenging. To control the measurement quality, a few MOX ceramic fuel pellets with known Pu amount are used. The results are evaluated by three kinds of methods (calibration curve, known- and multiplicity) to determine the best measurement method. In the range of concentration of typical samples, we could confirm good correlations between measured doubles and Pu effective mass in the three methods. Especially, the conventional calibration curve method showed a good performance with short measurement time and small uncertainty when the calibration standards were a good match to the unknown samples. In this paper, we present the INVS system design and measurement results with uncertainty using solution samples and comparison results among the three calibration methods.
Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Fujiki, Naoki*; Kado, Kazumi
JAEA-Technology 2013-050, 39 Pages, 2014/03
A uranium mass assay system NWAS, for 200-litter wastes drums applied by NDA method was developed and accumulated the data of the actual uranium bearing wastes drums. The system consists of the 16 pieces of Helium-3 proportional counters for neutron detection generated from U-234(,n) reaction or U-238 spontaneous fissions with polyethylene moderation and a Germanium solid state detector for ray detection as to determine uranium enrichment. The satisfactory works had been continued and the uranium determination data of 850 drums had been accumulated approximately. On the other hand several considerable problems on the system or methodology had been revealed technically or analytically through the measurements experiences. Furthermore as the next improvement plans, the active neutrons assay for uranium bearing wastes drums are now progressing. The results of complications will lead us to the progressive next steps.