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Shi, W.*; Machida, Masahiko; Yamada, Susumu; Okamoto, Koji*
Measurement, 258(Part D), p.119444_1 - 119444_15, 2026/01
Times Cited Count：1 Percentile：0.00(Engineering, Multidisciplinary)Nakamura, Hideo; Bentaib, A.*; Adorni, M.*
Proceedings of 20th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-20) (Internet), p.5668 - 5678, 2023/08
Nakamura, Hideo; Bentaib, A.*; Herranz, L. E.*; Ruyer, P.*; Mascari, F.*; Jacquemain, D.*; Adorni, M.*
Proceedings of International Conference on Topical Issues in Nuclear Installation Safety; Strengthening Safety of Evolutionary and Innovative Reactor Designs (TIC 2022) (Internet), 10 Pages, 2022/10
Soler, J. M.*; Neretnieks, I.*; Moreno, L.*; Liu, L.*; Meng, S.*; Svensson, U.*; Iraola, A.*; Ebrahimi, K.*; Trinchero, P.*; Molinero, J.*; et al.
Nuclear Technology, 208(6), p.1059 - 1073, 2022/06
Times Cited Count：8 Percentile：59.41(Nuclear Science & Technology)The SKB Task Force is an international forum on modelling of groundwater flow and solute transport in fractured rock. The WPDE experiments are matrix diffusion experiments in gneiss performed at the ONKALO underground facility in Finland. Synthetic groundwater containing several conservative and sorbing tracers was injected along a borehole interval. The objective of Task 9A was the predictive modelling of the tracer breakthrough curves from the WPDE experiments. Several teams, using different modelling approaches and codes, participated in this exercise. An important conclusion from this exercise is that the modelling results were very sensitive to the magnitude of dispersion in the borehole opening, which is related to the flow of water. Focusing on the tails of the breakthrough curves, which are more directly related to matrix diffusion and sorption, the results from the different teams were more comparable.
sp
Hard Rock Laboratory in SwedenTachi, Yukio; Ito, Tsuyoshi*; Gylling, B.*
Water Resources Research, 57(11), p.e2020WR029335_1 - e2020WR029335_20, 2021/11
Times Cited Count：6 Percentile：23.88(Environmental Sciences)This paper focuses on the scaling approach for sorption and diffusion parameters from laboratory to in-situ conditions using the dataset of LTDE-SD experiment performed at the sp HRL. The near-surface heterogeneities at both fracture surface and rock matrix could be evaluated by conceptual model with high porosity and diffusivity, and sorption capacity, and their gradual change at the near-surface zones. The modelling results for non-sorbing Cl-36 and weak-sorbing Na-22 could validate the model concept and the parameter estimation of porosity and diffusivity, by considering the disturbed zone of 5 mm thickness with gradual parameter changes. The De values of these cationic and anionic tracers showed typical cation excess and anion exclusion effects. The modelling results for high sorbing tracers (Cs-137, Ra-226, Ni-63 and Np-237) with different sorption mechanism could confirm the validity of the scaling approaches of Kd values as a function of particle size and their relation to the near-surface disturbances.
Mri, A.*; Mazurek, M.*; Ota, Kunio; Siitari-Kauppi, M.*; Eichinger, F.*; Leuenberger, M.*
Minerals (Internet), 11(10), p.1072_1 - 1072_17, 2021/10
Times Cited Count：8 Percentile：45.15(Geochemistry & Geophysics)Soler, J. M.*; Neretnieks, I.*; Moreno, L.*; Liu, L.*; Meng, S.*; Svensson, U.*; Trinchero, P.*; Iraola, A.*; Ebrahimi, H.*; Molinero, J.*; et al.
SKB R-17-10, 153 Pages, 2019/01
The SKB Task Force is an international forum on modeling of groundwater flow and solute transport in fractured rock. The WPDE experiments are matrix diffusion experiments in gneiss performed at the ONKALO underground facility in Finland. Synthetic groundwater containing several conservative and sorbing tracers was injected along a borehole interval. The objective of Task 9A was the predictive modeling of the tracer breakthrough curves from the WPDE experiments. Several teams, using different modelling approaches, participated in this exercise. An important conclusion from this exercise is that the modeling results were very sensitive to the magnitude of dispersion in the borehole opening, which is related to the flow of water. Focusing on the tails of the breakthrough curves, which are more directly related to matrix diffusion and sorption, the results from the different teams were more comparable. The modeling results have also been finally compared to the measured breakthroughs.
inert matrix fuelMiwa, Shuhei; Osaka, Masahiko
Journal of Nuclear Materials, 487, p.1 - 4, 2017/04
Times Cited Count：4 Percentile：30.75(Materials Science, Multidisciplinary)Oxidation and reduction behaviors of prototypic MgO-based inert matrix fuels (IMFs) containing PuO were experimentally investigated by means of thermogravimetry. The oxidation and reduction kinetics of the MgO-PuO specimen were determined. The oxidation and reduction rates of the MgO-PuO were found to be low compared with those of PuO. It is note that the changes in O/Pu ratios of MgO-PuO from stoichiometry were smaller than those of PuO at high oxygen partial pressure. From these results, it can be said that MgO matrix lower the oxygen supply and release of PuO, which is preferable as the minor actinides incineration devices, since the high oxygen potentials of minor actinide oxides can cause certain problems in terms of thermochemical aspects such as enlarged cladding inner-surface corrosion.
Kunieda, Satoshi; Shibata, Keiichi; Fukahori, Tokio; Kawano, Toshihiko*; Paris, M.*; Hale, G.*
JAEA-Conf 2015-003, p.33 - 38, 2016/03
We present recent progress of nuclear data evaluation method in the resolved resonance range. Our multi-channel R-matrix code now includes photon-channel and computational capability of charged-particle elastic scattering. We also present the physical constraint from the theory in the analysis of experimental data. Example analysis results are shown for 
Be and 
O compound system. Finally, perspectives are discussed toward the advancement of nuclear data in the resonance region including those for medium-heavy nuclei.
Al superconductors with Ta matrixTakeuchi, Takao*; Tagawa, Kohei*; Noda, Tetsuji*; Banno, Nobuya*; Iijima, Yasuo*; Kikuchi, Akihiro*; Kitaguchi, Hitoshi*; Kosuge, Michio*; Tsuchiya, Kiyosumi*; Koizumi, Norikiyo; et al.
IEEE Transactions on Applied Superconductivity, 16(2), p.1257 - 1260, 2006/06
Times Cited Count：6 Percentile：36.50(Engineering, Electrical & Electronic)Next generation nuclear fusion magnets would require a high-current conductor in fields more than 16 T. A CIC conductor of the rapid RHQT processed NbAl may be a promising candidate. Good deformability of intermediately-formed bcc supersaturated-solid solution indeed allowed fabricating such a CIC conductor, which would be subsequently transformation annealed. Ag has been internally included as a basic constituent of a round strand so far, because Ag is almost non-reactive with Nb matrix during the RHQ. However, both of Ag and Nb are not suitable nuclei from the viewpoint of radioactivity when irradiated with neutrons. Recently, we have succeeded in replacing the Nb matrix with Ta that has the advantage of shorter half-life of radioactivity. In the present study, an attempt has been made to replace the Ag internal stabilizer with Cu, in the aim of further reducing radioactivity, based on anticipation that Ta would be less reactive with Cu than Nb did.
Nakajima, Kunihisa; Iwai, Takashi; Kikuchi, Hironobu; Serizawa, Hiroyuki; Arai, Yasuo
JAERI-Research 2005-027, 42 Pages, 2005/09
JAERI-Research-2005-027.pdf:4.15MB
Nitride fuel pins containing inert matrix such as ZrN and TiN were fabricated for the irradiation test at JMTR, aiming at understanding irradiation behavior of nitride fuel for transmutation of minor actinides. Minor actinides are surrogated by plutonium in the present fuel pin. This report describes the preparation and characterization of fuel pellets, and fabrication of fuel pins. The irradiation for 11 cycles from May 2002 to November 2004 at JMTR was completed without any failure of fuel pins.
Aiba, Nobuyuki*; Tokuda, Shinji; Ishizawa, Tomoko*; Okamoto, Masao*
Plasma Physics and Controlled Fusion, 46(11), p.1699 - 1721, 2004/11
Times Cited Count：3 Percentile：9.60(Physics, Fluids & Plasmas)The theory of the Newcomb equation has been applied to low-n external modes in a tokamak and a method has been developed to compute the stability matrix that gives the change of plasma potential energy due to external modes in terms of the surface values of the perturbations. By using this method, the spectral properties of the ideal external modes has been elucidated, such as coupling between external modes and internal modes, and the difference of the stability properties between a normal shear tokamak and a reversed shear tokamak. These results will be also useful in the stability analysis of resistive wall modes.
Hajima, Ryoichi
Nuclear Instruments and Methods in Physics Research A, 528(1-2), p.335 - 339, 2004/08
Times Cited Count：24 Percentile：79.88(Instruments & Instrumentation)Dilution of electron beam emittance through a return arc is one of critical problems in the design of an energy-recovery linac for high-power FEL and a synchrotron light source. We present that the emittance dilution can be compensated by establishing the matching between the phase ellipse orientation and the CSR kick direction, and the effect of coherent synchrotron radiation on the beam emittance dilution can be estimated from simple calculation of transfer matrices.
Hajima, Ryoichi
Japanese Journal of Applied Physics, Part 2, 42(8A), p.L974 - L976, 2003/08
Times Cited Count：23 Percentile：63.20(Physics, Applied)A first-order transform matrix is proposed to calculate electron beam emittance dilution arising from coherent synchrotron radiation (CSR) in a next-generation light source based on an energy-recovery linac. The matrix approach enable us to scan a lot of parameters for the design of achromatic cells of minimum emittance dilution. The emitatce dilution can be minimized when the CSR wake dispersion matches to the betatron function envelope at the achromatic cell exit.
Hajima, Ryoichi
Proceedings of 28th Linear Accelerator Meeting in Japan, p.288 - 290, 2003/08
no abstracts in English
Yamashita, Toshiyuki; Kuramoto, Kenichi; Akie, Hiroshi; Nakano, Yoshihiro; Shirasu, Noriko; Nakamura, Takehiko; Kusagaya, Kazuyuki*; Omichi, Toshihiko*
Journal of Nuclear Science and Technology, 39(8), p.865 - 871, 2002/08
Times Cited Count：26 Percentile：81.11(Nuclear Science & Technology)Research on the plutonium rock-like oxide (ROX) fuels and their once-through burning in light water reactors has been performed to establish an option for utilizing and disposing effectively the excess plutonium. The ROX fuel is a sort of the inert matrix fuels and consists of mineral-like compounds such as yttria stabilized zirconia, spinel and corundum. A particle-dispersed fuel was devised to reduce damage by heavy fission fragments. Some preliminary results on swelling, fractional gas release and microstructure change for five ROX fuels were obtained from the irradiation test and successive post-irradiation examinations. Inherent disadvantages of the Pu-ROX fuel cores could be improved by adding 238U or 232Th as resonant materials, and all improved cores showed a nearly the same characteristics as the conventional UO2 core during transient conditions. The threshold enthalpy of the ROX fuel rod failure was found to be comparable to the fresh UO2 rod by pulse-irradiation tests simulating reactivity initiated accident conditions.
, 
, and 
with the Reich-Moore 
-matrix theory for JENDL-3.2Kawano, Toshihiko*; Shibata, Keiichi
Journal of Nuclear Science and Technology, 39(8), p.807 - 815, 2002/08
Times Cited Count：6 Percentile：38.36(Nuclear Science & Technology)A simple method to estimate covariances for resolved resonance parameters was developed. Although a large number of resolved resonances are observed for major actinides, uncertainties in averaged cross sections are more important than those in resonance parameters in reactor calculations. The method developed here is to derive a covariance matrix for the resolved resonance parameters which gives an appropriate uncertainty of the averaged cross sections. The method was adopted to evaluate the covariance data for , , and resonance parameters in JENDL-3.2,with the Reich-Moore R-matrix formula.
Fujita, Ayumi
Physical Review B, 64(6), p.064504_1 - 064504_6, 2001/08
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)We study parametric level statistics of the discretized excitation spectra inside a moving vortex core in layered superconductors with impurities. The universal conductivity is evaluated numerically for the various values of rescaled vortex velocities 
from the clean case to the dirty limit case. The random matrix theoretical prediction is verified numerically in the large regime. On the contrary in the low velocity regime, we observe 
which is consistent with the theoretical result for the super-clean case, where the energy dissipation is due to the Landau-Zener transition which takes place at the points called ``avoided crossing''.
; ;
JAERI-Data/Code 99-016, 183 Pages, 1999/03
JAERI-Data-Code-99-016.pdf:4.87MB
no abstracts in English
Suyama, Kenya; Masukawa, Fumihiro*; ; ; ;
JAERI-Data/Code 97-021, 86 Pages, 1997/06
JAERI-Data-Code-97-021.pdf:2.3MB
no abstracts in English
