PSTEP: Project for solar-terrestrial environment prediction

Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.

Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12

https://doi.org/10.1186/s40623-021-01486-1

The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.

Technical report on the development of finance and contract information system Ver.4

Kimura, Hideo; Hikasa, Naoki*; Kugenuma, Yuji*; Doi, Toshiharu*; Kikuchi, Yoshitaka*

JAEA-Technology 2019-004, 25 Pages, 2019/05

JAEA-Technology-2019-004.pdf:3.02MB

JAEA has developed the "Financial and contract information system" for effective and efficient accomplishment of the mission-critical tasks. Because the development of the next system was necessary with the end in the support time limit of the current system, we carried out the development of the next system in 2018. While the addition of the electronic approval function or the adoption of the latest package software largely performed a functional enhancement until now by applying distributed systems construction technique based on the separation procurement that we devised progressively, in development, we extremely realized procurement with the low cost.

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2015

Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Nagaoka, Mika; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.

JAEA-Review 2017-001, 115 Pages, 2017/03

JAEA-Review-2017-001.pdf:3.57MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2015. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

Design and manufacture of Joyo upper core structure for replacement

Ota, Katsu; Ushiki, Hiroshi*; Maeda, Shigetaka; Kawahara, Hirotaka; Takamatsu, Misao; Kobayashi, Tetsuhiko; Kikuchi, Yuki; Tobita, Shigeharu; Nagai, Akinori

JAEA-Technology 2015-026, 180 Pages, 2015/11

JAEA-Technology-2015-026.pdf:79.87MB

In the experimental fast reactor Joyo, it was confirmed that the top of the irradiation test sub-assembly of "MARICO-2" (material testing rig with temperature control) had bent onto the in-vessel storage rack as an obstacle and had damaged the upper core structure (UCS). The replacement of the UCS was conducted from May to December 2014. The design and manufacture of UCS was started from 2008, and the installation of UCS was completed successfully in November 21th 2014. The major results gained during the design and manufacture of UCS is as follows.

Generation of spin currents by surface plasmon resonance

Uchida, Kenichi*; Adachi, Hiroto; Kikuchi, Daisuke*; Ito, Shun*; Qiu, Z.*; Maekawa, Sadamichi; Saito, Eiji

Nature Communications (Internet), 6, p.5910_1 - 5910_8, 2015/01

https://doi.org/10.1038/ncomms6910

Spin-relaxation modulation and spin-pumping control by transverse spin-wave spin current in YFeO

Kajiwara, Yosuke*; Uchida, Kenichi*; Kikuchi, Daisuke*; An, Toshu*; Fujikawa, Yasunori*; Saito, Eiji

Applied Physics Letters, 103(5), p.052404_1 - 052404_4, 2013/07

https://doi.org/10.1063/1.4817076

Heat-current-induced manipulation of spin relaxation in YFeO under an in-plane temperature gradient is investigated. We show that the linewidth of the ferromagnetic resonance spectrum, i.e., the spin relaxation, in an YFeO film increases or decreases depending on the temperature-gradient direction and that this modulation is attributed to the spin-transfer torque caused by a thermally induced transverse spin-wave spin current in the YFeO film. The experimental results also show that the spin-current magnitude generated by spin pumping in an attached Pt film is inversely proportional to the square of the modulated Gilbert damping constant, consistent with a phenomenological spin-pumping model.

Stability of pyrrolidone derivatives against -ray irradiation

Nogami, Masanobu*; Sugiyama, Yuichi*; Kawasaki, Takeshi*; Harada, Masayuki*; Kawata, Yoshihisa*; Morita, Yasuji; Kikuchi, Toshiaki*; Ikeda, Yasuhisa*

Science China; Chemistry, 55(9), p.1739 - 1745, 2012/09

https://doi.org/10.1007/s11426-012-4698-3

Stability of N-alkylated pyrrolidone derivatives (NRPs) against radiation was examined by irradiation tests with Co -ray. We have been developed a novel reprocessing system using NRPs which have precipitation ability to haxa- and tetravalent actinides in nitric acid media. Degradation rates of NRPs are evaluated by irradiation in 3M nitric acid solutions and mechanism of degradation are discussed in the present paper.

The Distinct element analysis for swelling pressure test of bentonite; Discussion on the effects of wall friction force and aspect ratio of specimen

Shimizu, Hiroyuki*; Kikuchi, Hirohito; Tanai, Kenji; Fujita, Tomoo

JAEA-Research 2011-024, 74 Pages, 2011/10

JAEA-Research-2011-024.pdf:7.23MB

For geological isolation systems for HLW, due to the lack of standardization of swelling test method for bentonite as a buffer material, the accuracy and reproducibility of the results are not sufficiently proved. In this study, bentonite swelling pressure test were simulated by newly developed distinct element method, and the effects of wall friction force and aspect ratio of bentonite specimen were discussed.

Survey on current status of laboratory test method and experimental consideration for establishing standardized procedure of material containing bentonite; Report of Collaboration Research between JAEA and CRIEPI (Joint research)

Tanai, Kenji; Kikuchi, Hirohito; Nakamura, Kunihiko*; Tanaka, Yukihisa*; Hironaga, Michihiko*

JAEA-Research 2010-025, 186 Pages, 2010/08

JAEA-Research-2010-025.pdf:9.01MB

Bentonite-based material is used as one of the components of the LLW, TRU and HLW disposal facilities. Required characteristics of bentonite-based material are low permeability, swelling property, etc. Those are evaluated in many cases by laboratory test results. However the uncertainty exists in the evaluation of those characteristics in construction. Because even if the index of the dry density etc is the same, laboratory test results have variability. In addition, the uncertainty in construction has the possibility to increase the uncertainty of long-term evaluation of characteristics. On the other hand, several of laboratory test methods of bentonite are not standardized. So, this is a possibility that is one of the uncertain causes of the evaluation of characteristics of the bentonite. Therefore, it is hoped that the laboratory tests of bentonite are standardized. Therefore, this study analysis the uncertainty on the physical properties by laboratory tests and put together the problem and ponts of concern in the tests.

Development of separation technology of Mo by using iron oxide adsorbents (Contract research)

Kikuchi, Takahiro; Hoshi, Harutaka; Asakura, Toshihide; Morita, Yasuji; Kimura, Takaumi; Dodbiba, G.*; Fujita, Toyohisa*

JAEA-Research 2010-010, 45 Pages, 2010/07

JAEA-Research-2010-010.pdf:1.31MB

We have investigate that separation of Mo from simulated HLLW using various metal oxides adsorbent. Fe-Pb oxides and manganese oxide showed very high solubility in nitric acid solution. The distribution coefficient of Mo was decreased with increasing nitric acid concentration among tested adsorbents. Adsorption ability of Mo on alumina and cobalt oxide was low in 3M nitric acid. Hematite type iron oxide (Fe adsorbent) and amorphous zirconium oxide had high Mo adsorption ability, in 3M nitric acid. TRU, U and major fission products were not adsorbed on the adsorbent. So, separation of Mo can be achieved by using Fe adsorbent. A part of Mo was adsorbed irreversibly on Fe adsorbent, but reversibly-adsorbed Mo was recovered by oxalic acid, and the adsorbent was able to use repeatedly. Behavior of break-through of Mo is estimated from adsorption isotherm and overall mass transfer coefficient. We found that amount of throughput of Mo increased with decreasing grain size of the adsorbent.