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.

Progress report of Japanese simulation research projects using the high-performance computer system Helios in the International Fusion Energy Research Centre

Ishizawa, Akihiro*; Idomura, Yasuhiro; Imadera, Kenji*; Kasuya, Naohiro*; Kanno, Ryutaro*; Satake, Shinsuke*; Tatsuno, Tomoya*; Nakata, Motoki*; Nunami, Masanori*; Maeyama, Shinya*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.157 - 210, 2016/03

http://www.jspf.or.jp/Journal/PDF_JSPF/jspf2016_03/jspf2016_03-157.pdf

The high-performance computer system Helios which is located at The Computational Simulation Centre (CSC) in The International Fusion Energy Research Centre (IFERC) started its operation in January 2012 under the Broader Approach (BA) agreement between Japan and the EU. The Helios system has been used for magnetised fusion related simulation studies in the EU and Japan and has kept high average usage rate. As a result, the Helios system has contributed to many research products in a wide range of research areas from core plasma physics to reactor material and reactor engineering. This project review gives a short catalogue of domestic simulation research projects. First, we outline the IFERC-CSC project. After that, shown are objectives of the research projects, numerical schemes used in simulation codes, obtained results and necessary computations in future.

Development of the 170GHz gyrotron and equatorial launcher for ITER

Sakamoto, Keishi; Kasugai, Atsushi; Takahashi, Koji; Minami, Ryutaro*; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Kobayashi, Noriyuki

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03

http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/html/node470.htm#93615

no abstracts in English

Long pulse operation of 170 GHz ITER gyrotron by beam current control

Kasugai, Atsushi; Minami, Ryutaro; Takahashi, Koji; Kobayashi, Noriyuki; Sakamoto, Keishi

Fusion Engineering and Design, 81(23-24), p.2791 - 2796, 2006/11

https://doi.org/10.1016/j.fusengdes.2006.07.077

In JAEA (Japan Atomic Energy Agency, formerly JAERI), development of 170 GHz, 1 MW, CW gyrotron for ITER has been carried out. Key technologies for ITER gyrotron such as a diamond window, a depressed collector for high efficiency operation and a stable operation at 170 GHz/1 MW with higher mode TE31,8 have been developed. By integration of these key technologies, gyrotron performance of 0.5 MW/ 100 sec and 0.9 MW/ 9.2 sec were demonstrated. Hence, next target is a demonstration of long pulse operation. One of the issues which prevent the pulse extension is large beam current decrease due to so called the emission cooling of a cathode. During the operation, the oscillation mode shift from TE31,8 to TE30,8 was caused by the current decrease. Then, the magnetic field of the cavity should be increased to avoid the downshift of the oscillation mode, however, the efficiency decreases and the parasitic oscillation appears in a quasi-optical mode converter. To suppress the beam current decrease and to demonstrate the long pulse operation of the high power gyrotron, pre-programming control of the cathode heater power was applied and the long pulse experiment was carried out to sustain the beam current. As a result, stable electron beam of 1000 s, which is required for ITER operation, was demonstrated without oscillation, and pre-programming control directed the effectiveness for constant beam current. Moreover, in the experiment of the long pulse oscillation with oscillation, the pre-programming control suppressed the beam current decrease. Up to now, stable long pulse operation of 8 minutes with 0.2 MW output power was obtained. The output energy of the oscillation is maximum value in the 170GHz ITER gyrotron. Since overheating due to stray radiation inside the gyrotron limit the pulse extension, long pulse operation with high power output will be achieved by enhancement of the cooling and reduction of stray radiation due to modification of a built-in mode converter.

The Designs of high efficiency launcher of quasi-optical mode converter for high power gyrotrons

Minami, Ryutaro; Kasugai, Atsushi; Takahashi, Koji; Kobayashi, Noriyuki*; Mitsunaka, Yoshika*; Sakamoto, Keishi

International Journal of Infrared and Millimeter Waves, 27(1), p.13 - 24, 2006/01

https://doi.org/10.1007/s10762-006-9078-7

no abstracts in English

Development of high power gyrotron for CW operation

Minami, Ryutaro; Kasugai, Atsushi; Takahashi, Koji; Kobayashi, Noriyuki; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Hayashi, Kenichi*; Sakamoto, Keishi

Shingaku Giho, 105(498), p.39 - 42, 2005/12

no abstracts in English

Long pulse operation of high power gyrotron with mm-wave range for fusion reactor

Kasugai, Atsushi; Minami, Ryutaro; Takahashi, Koji; Kobayashi, Noriyuki*; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Hayashi, Kenichi*; Sakamoto, Keishi

Shingaku Giho, 104(520), p.37 - 42, 2004/12

no abstracts in English

Development of advanced antennas and diamond windows for ECH/CD in fusion reactor

Takahashi, Koji; Kasugai, Atsushi; Minami, Ryutaro; Sakamoto, Keishi; Ikeda, Yukiharu; Kobayashi, Noriyuki*; Imai, Tsuyoshi

Denki Gakkai Genshiryoku Kenkyukai Shiryo (NE-03-1), p.1 - 6, 2003/09

no abstracts in English

Estimation of thermochemical behavior of spallation products in mercury target

Kobayashi, Kaoru*; Kaminaga, Masanori; Haga, Katsuhiro; Kinoshita, Hidetaka; Aso, Tomokazu; Teshigawara, Makoto; Hino, Ryutaro

JAERI-Tech 2002-005, 118 Pages, 2002/02

JAERI-Tech-2002-005.pdf:9.71MB

In order to examine the radiation safety of a spallation mercury target system, it is necessary to clarify the chemical forms of spallation products generated by spallation reaction with proton beam. As for the chemical forms of spallation products in mercury that involves large amounts of spallation products, these forms were estimated by using the binary phase diagrams and the thermochemical equilibrium calculation based on the amounts of spallation product. Calculation results showed that the mercury would dissolve Al, As, B, Be, Bi, C, Co, Cr, Fe, Ga, Ge, Ir, Mo, Nb, Os, Re, Ru, Sb, Si, Ta, Tc, V and W in the element state, and Ag, Au, Ba, Br, Ca, Cd, Ce, Cl, Cs, Cu, Dy, Er, Eu, F, Gd, Hf, Ho, I, In, K, La, Li, Lu, Mg, Mn, Na, Nd, Ni, O, Pb, Pd, Pr, Pt, Rb, Rh, S, Sc, Se, Sm, Sn, Sr, Tb, Te, Ti, Tl, Tm, Y, Yb, Zn and Zr in the form of inorganic mercury compounds.

Physical and thermochemical properties for inorganic mercury compounds

Kobayashi, Kaoru*; Kaminaga, Masanori; Haga, Katsuhiro; Kinoshita, Hidetaka; Aso, Tomokazu; Kogawa, Hiroyuki; Hino, Ryutaro

JAERI-Data/Code 2000-037, 69 Pages, 2000/12

JAERI-Data-Code-2000-037.pdf:3.21MB

no abstracts in English