Phase analysis of simulated nuclear fuel debris synthesized using UO, Zr, and stainless steel and leaching behavior of the fission products and matrix elements

Tonna, Ryutaro*; Sasaki, Takayuki*; Kodama, Yuji*; Kobayashi, Taishi*; Akiyama, Daisuke*; Kirishima, Akira*; Sato, Nobuaki*; Kumagai, Yuta; Kusaka, Ryoji; Watanabe, Masayuki

Nuclear Engineering and Technology, 55(4), p.1300 - 1309, 2023/04

https://doi.org/10.1016/j.net.2022.12.017

Simulated debris was synthesized using UO, Zr, and stainless steel and a heat treatment method under inert or oxidizing conditions. The primary U solid phase of the debris synthesized at 1473 K under inert conditions was UO, whereas a (U,Zr)O solid solution formed at 1873 K. Under oxidizing conditions, a mixture of UO and (Fe,Cr)UO phases formed at 1473 K whereas a (U,Zr)O solid solution formed at 1873 K. The leaching behavior of the fission products from the simulated debris was evaluated using two methods: the irradiation method, for which fission products were produced via neutron irradiation, and the doping method, for which trace amounts of non-radioactive elements were doped into the debris. The dissolution behavior of U depended on the properties of the debris and aqueous medium the debris was immersed in. Cs, Sr, and Ba leached out regardless of the primary solid phases. The leaching of high-valence Eu and Ru ions was suppressed, possibly owing to their solid-solution reaction with or incorporation into the uranium compounds of the simulated debris.

KeV-neutron capture cross-section measurement of Au with a Cr-filtered neutron beam at the ANNRI beamline of MLF/J-PARC

Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Katabuchi, Tatsuya*; Kodama, Yu*; Nakano, Hideto*; Sato, Yaoki*; et al.

Journal of Nuclear Science and Technology, 59(5), p.647 - 655, 2022/05

https://doi.org/10.1080/00223131.2021.1997666

Measurements of the neutron capture cross section of Am around 23.5 keV

Kodama, Yu*; Katabuchi, Tatsuya*; Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Nobuyuki; Iwamoto, Osamu; Hori, Junichi*; Shibahara, Yuji*; et al.

Journal of Nuclear Science and Technology, 58(11), p.1159 - 1164, 2021/11

https://doi.org/10.1080/00223131.2021.1943557

Neutron capture cross section measurement of minor actinides in fast neutron energy region for study on nuclear transmutation system

Katabuchi, Tatsuya*; Hori, Junichi*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Kimura, Atsushi; Nakamura, Shoji; Shibahara, Yuji*; Terada, Kazushi*; Tosaka, Kenichi*; Endo, Shunsuke; et al.

JAEA-Conf 2020-001, p.5 - 9, 2020/12

https://doi.org/10.11484/jaea-conf-2020-001

Revealing the second harmonic generation in a femtosecond laser-driven cluster-based plasma by analyzing shapes of Ar XVII spectral lines

Oks, E.*; Dalimier, E.*; Faenov, A.*; Pikuz, T.*; Fukuda, Yuji; Andreev, A.*; Koga, J. K.; Sakaki, Hironao; Kotaki, Hideyuki; Pirozhkov, A. S.; et al.

Optics Express (Internet), 23(25), p.31991 - 32005, 2015/12

https://doi.org/10.1364/OE.23.031991

We present experiments dealing with a femtosecond laser-driven cluster-based plasma, where by analyzing the nonlinear phenomenon of satellites of spectral lines of Ar XVII, we revealed the nonlinear phenomenon of the generation of the second harmonic of the laser frequency. For performing this analysis we developed new results in the theory of satellites of spectral lines. From such lineshape analysis we found, in particular, that the efficiency of converting the short (40 fs) intense (310 W/cm) incident laser light into the second harmonic was 2%. This result is in the excellent agreement with the 2-Dimensional Particle-In-Cell (2D PIC) simulation that we also performed. There is also an order of magnitude agreement between the thresholds for the SHG found from the line shape analysis and from the 2D PIC simulations.

Development of beryllium material for reflector lifetime expansion

Dorn, C. K.*; Tsuchiya, Kunihiko; Hatano, Yuji*; Chakrov, P.*; Kodama, Mitsuo*; Kawamura, Hiroshi

Proceedings of 5th International Symposium on Material Testing Reactors (ISMTR-5) (Internet), 9 Pages, 2012/10

http://www.murr.missouri.edu/ismtr/papercall/Papers/JAEA/Tsuchiya_ISMTR-5_instruments(Takeuchi).pdf

The JMTR has used beryllium reflector since it began operation in 1968. Beryllium has been used as the reflector element material in the reactor, specifically S-200F structural grade beryllium in JMTR. As a part of the reactor upgrade, the Japan Atomic Energy Agency (JAEA) has carried out the cooperation experiments to extend the operating lifetime of the beryllium reflector elements. Thus, three kinds of beryllium metals such as S-200F, S-65H and I-220H were selected at the viewpoints of production methods, impurities and grain size of beryllium starting powders, mechanical properties. Now, data of the material properties and interaction between pure water and these beryllium grades are accumulated under un-irradiated. Additionally, irradiation tests have been prepared and development of PIE technologies has been performed. In this paper, the results of various properties and irradiation test plan for lifetime expansion of beryllium are described for material testing reactors.

Investigation for methods of micro-structural observation of beryllium metals by TEM

Ito, Masayasu; Kawamata, Kazuo; Sozawa, Shizuo; Shibata, Akira; Tsuchiya, Kunihiko; Kitsunai, Yuji*; Kodama, Mitsuhiro*

JAEA-Testing 2011-003, 22 Pages, 2011/06

JAEA-Testing-2011-003.pdf:9.16MB

In JMTR, beryllium metal is used for neutron reflector. However, the periodical exchange of the neutron reflector is necessary due to degradation of strength and swelling under neutron irradiation. So it is required to select the material that bears long term from the viewpoint of the utilization rate improvement and the radioactive waste decrease in JMTR. It is important to evaluate the characteristics of beryllium metals precisely. This report describes the preparation method of the sample and observation results by the transmission electron microscope that is being examined as a evaluation method of the beryllium metal.

Characterization of electron self-injection in laser wake field acceleration due to the parametric resonance

Zhidkov, A.*; Koga, J. K.; Hosokai, Tomonao*; Fujii, Takashi*; Oishi, Yuji*; Nemoto, Koshichi*; Kodama, Ryosuke*

Physics of Plasmas, 17(8), p.083101_1 - 083101_6, 2010/08

https://doi.org/10.1063/1.3458669

Ion acceleration in the interaction of short pulse laser radiation with the cluster-gas target

Fukuda, Yuji; Faenov, A. Y.; Tampo, Motonobu; Pikuz, T. A.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Yogo, Akifumi; Sakaki, Hironao; Kameshima, Takashi; et al.

AIP Conference Proceedings 1153, p.85 - 93, 2009/07

https://doi.org/10.1063/1.3204561

When the target consists of solid-density clusters embedded in the background gas, its irradiation by high intensity laser light renders ion acceleration a truly unique property. We present that the cluster-gas target, which consists of submicron-sized clusters and background gases, irradiated by a few TW laser pulse produces high energy ions upward of the order of 10-20 MeV/n in the forward direction.

Development of the Chopper spectrometer 4SEASONS at J-PARC

Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakajima, Kenji; Nakamura, Mitsutaka; Inamura, Yasuhiro; Maruyama, Ryuji; Soyama, Kazuhiko; Suzuya, Kentaro; Ino, Takashi*; Oyama, Kenji*; et al.

no journal, , 

4SEASONS is a chopper-type inelastic neutron spectrometer, and one of the day-one instruments at the spallation neutron source facility in Japan Proton Accelerator Research Complex (J-PARC). The targeted energy range is 5-300meV, and the spectrometer is optimized in intensity in this energy range by moderating the resolutions (% at ), by incorporating an efficient beam transport system, and by realizing multi incident energy () measurement. The high intensity and efficiency available at 4SEASONS make this spectrometer suitable for study of novel quantum phenomena in high- superconductors and related systems. In the present paper, we will report the current status of the development and the construction of 4SEASONS, such as construction of the vacuum tank and the shielding, development of the new Fermi chopper for the multi- measurement, 2.5m-long He PSDs, and the beam transport system.