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.

Dynamical behavior of human -synuclein studied by quasielastic neutron scattering

Fujiwara, Satoru; Araki, Katsuya*; Matsuo, Tatsuhito; Yagi, Hisashi*; Yamada, Takeshi*; Shibata, Kaoru; Mochizuki, Hideki*

PLOS ONE (Internet), 11(4), p.e0151447_1 - e0151447_17, 2016/04

https://doi.org/10.1371/journal.pone.0151447

Compact neutron sources for energy and security

Uesaka, Mitsuru*; Kobayashi, Hitoshi*; Kureta, Masatoshi; Nakatsuka, Shigehiro*; Nishimura, Kazuya*; Igashira, Masayuki*; Hori, Junichi*; Kiyanagi, Yoshiaki*; Tagi, Kazuhiro*; Seki, Toshichika*; et al.

Reviews of Accelerator Science and Technology, 8, p.181 - 207, 2015/00

https://doi.org/10.1142/S1793626815300108

We choose nuclear data and nuclear material inspection for energy application and nondestructive testing of explosive and hidden nuclear materials for security application. 90 keV electrostatic accelerators of deuterium are commercially available for nondestructive testing. For nuclear data measurement, electrostatic ion accelerators and L-band and S-band electron linear accelerators (linac) are used for the neutron source. Compact or mobile X-band electron linac neutron sources are under development. Compact proton linac neutron source is used for nondestructive testing especially water in solids. Several efforts for more neutron intensity using proton and deuteron accelerators are also introduced.

Preparation of hydrous titanic acid as an inorganic ion exchanger for Sr recovery

Fujiwara, Takeshi

JAEA-Testing 2012-004, 13 Pages, 2012/11

JAEA-Testing-2012-004.pdf:2.7MB

In the 4-Group partitioning process developed in Japan Atomic Energy Research Institute (presently: Japan Atomic Energy Agency), a heat-generating nuclide group including Sr and Cs is separated by inorganic ion exchangers. Hydrous titanic acid and zeolite are used as the inorganic ion exchangers. The mechanical durability of the particles of hydrous titanic acid used for Sr recovery is not enough in case of mixing with zeolite used for Cs recovery. The method of drying the hydrous titanic acid was improved to provide sufficient mechanical durability to the product of hydrous titanic acid in case of mixing with zeolite. A procedure of producing hydrous titanic acid from the raw material, titanyl sulfate, was established and documented with cares to be taken at each step.

Development and management of the knowledge base for the geological disposal technology; Annual report 2006

Umeda, Koji; Oi, Takao; Osawa, Hideaki; Oyama, Takuya; Oda, Chie; Kamei, Gento; Kuji, Masayoshi*; Kurosawa, Hideki; Kobayashi, Yasushi; Sasaki, Yasuo; et al.

JAEA-Review 2007-050, 82 Pages, 2007/12

JAEA-Review-2007-050.pdf:28.56MB

This report shows the annual report which shows the summarized results and topic outline of each project on geological disposal technology in the fiscal year of 2006.

Separation of rare earth elements by continuous stripping with DTPA from DIDPA solvent

Fujiwara, Takeshi; Morita, Yasuji

Nihon Genshiryoku Gakkai Wabun Rombunshi, 6(3), p.358 - 364, 2007/09

https://doi.org/10.3327/taesj.J06.064

Continuous stripping of rare earth elements (REs) with diethylenetriaminepentaacetic acid (DTPA) solution from the diisodecylphosphoric acid (DIDPA) solvent was examined with lab-scale mixer-settlers, to develop a process for the separation of trivalent actinides (An(III)) from the mixture of An(III) and REs. DIDPA is an extractant applied in the 4-Group Partitioning Process developed in Japan Atomic Energy Research Institute (presently: Japan Atomic Energy Agency) to separate transuranic elements from high-level liquid waste. The experiment on continuous stripping with the DTPA solution of a little higher pH than an appropriate pH for selective stripping of An(III) showed that Nd could be selectively stripped from the DIDPA solvent containing La and Nd. The yield was higher than 99.8%, and 97.6% of La was left in the solvent. The pH of the DTPA solution decreased in the stages near the solvent feed, which was explained by the extraction of ammonium ion. These findings make it possible to predict quantitatively the behavior of An(III) and REs in the various conditions of the DIDPA-DTPA continuous stripping system.

Announced document collection of the 1st Information Exchange Meeting on Radioactive Waste Disposal Research Network (Joint research)

Nakayama, Shinichi; Nagasaki, Shinya*; Inagaki, Yaohiro*; Oe, Toshiaki*; Sasaki, Takayuki*; Sato, Seichi*; Sato, Tsutomu*; Tanaka, Satoru*; Tochiyama, Osamu*; Nagao, Seiya*; et al.

JAEA-Conf 2007-003, 120 Pages, 2007/03

JAEA-Conf-2007-003.pdf:53.18MB

The 1st information exchange meeting on Radioactive Waste Disposal Research Network was held in Nuclear Science Research Institute of Japan Atomic Energy Agency on August 4, 2006. Radioactive Waste Disposal Research Network was established by under Interorganization Atomic Energy Research Program of Japan Atomic Energy Agency, and the objective is to bring both research infrastructures and human expertise in Japan to an adequate performance level, thereby contributing to the development of the fundamental research area in the field of radioactive waste disposal. This lecture material is a collection of research presentations and discussions during the information exchange meeting.

Effects of tungsten on microstructure and high-temperature strength of oxide dispersion strengthened (ODS) martensitic steel

Narita, Takeshi*; Ukai, Shigeharu; Kaito, Takeji; Otsuka, Satoshi; Fujiwara, Masayuki

JAEA-Research 2006-050, 85 Pages, 2006/10

JAEA-Research-2006-050.pdf:133.32MB

In 9Cr ODS martensitic steel, tungsten(W) is a solid solution strengthening element, whose addition increases high-temperature strength by the combined effect with oxide dispersion strengthening. However, its excessive addition results in the increase of ferrite phase causing precipitation of intermetallic compound (Laves phase) under high temperature irradiation condition and thus ductility degradation. The amount of W addition therefore should be as low as possible. In this report, the effects of W on microstructure and high temperature mechanical properties of 9Cr ODS martensitic steels were examined for obtaining insights into optimum W concentration in terms of high-temperature strength and ductility. The results obtained are as follows: (1)In the 9CrODS martensitic steel, addition of W exceeding 2mass% is shown to cause precipitation of Laves phase which degrades the ductility and fracture toughness. It can be said that the current specification of W concentration, i.e. 2mass%W, is appropriate. (2)Hardness and tensile strength is shown to increase with W concentration. This increase is caused by the increase of solid solution strengthening and residual-alpha ferrite. The retainment of residual-alpha ferrite is enhanced by the addition of W (ferrite former element). The improvement of tensile strength at 973K provided by the solid solution strengthening is shown to be equivalent to that provided by the retainment of residual-alpha ferrite. (3)It would be open task to explorer an improved alloy design concept, i.e. decrease of W as low as possible and increase of residual-alpha ferrite. The degradation of high-temperature strength by decreasing W addition can be made up by the increasing fraction of residual-alpha phase that is provided by reduction of austenite former elements and increasing addition of ferrite former elements.

Study on applicability of DIDPA solvent to Talspeak method

Fujiwara, Takeshi; Morita, Yasuji

JAEA-Research 2006-011, 24 Pages, 2006/03

JAEA-Research-2006-011.pdf:1.43MB

In the 4-Group Partitioning Process developed in Japan Atomic Energy Research Institute (presently: Japan Atomic Energy Agency), the transuranic element and the rare earth elements are extracted from high-level liquid waste by diisodecylphosphoric acid (DIDPA). The concentration of the rare earth elements are about 50 times higher than that of Am and Cm in high-level liquid waste. It is, therefore, necessary to separate each other for the transmutation of Am and Cm, or volume reduction of the waste form of the long-lived nuclide. On the other hand, the Talspeak method is a separation method by the solvent extraction that gives selective stripping of Am and Cm from the solvent that contains the rare earth elements using di-2-ethylhexylphosphoric acid (DEHPA) as an extractant. In the present study, application of the DIDPA to the Talspeak method was examined for various conditions to separate Am from the rare earth elements by the batch examination.

Treatment and decomposition of HLW-79Y-4T type transportation cask for liquid radioactive fuel material

Yamaguchi, Isoo*; Morita, Yasuji; Fujiwara, Takeshi; Yamagishi, Isao

JAERI-Tech 2005-054, 61 Pages, 2005/09

JAERI-Tech-2005-054.pdf:12.38MB

The HLW-79Y-4T type transportation cask for liquid radioactive fuel material (commonly called "Cendrillon") was imported from France and modified for Japanese regulation in order to obtain high-level radioactive liquid waste (HLW) for partitioning tests in JAERI by transportation from Tokai Establishment of Japan Nuclear Fuel Cycle Development Institute. The cask was used for the HLW transportation five times from 1982 to 1990. After that, it was kept and maintained for next transportation of HLW from facilities outside JAERI. Finally, we decided to decompose the cask because HLW can be obtained in JAERI Tokai. For the decomposition, radiation dose and contamination by radioactivity was first measured and then the methods to reduce those levels were determined. The cask was decomposed after the decontamination to separate the part that has high radiation level. The separated part was put in a vessel specially prepared. The present report describes those procedures for the decomposition of the transportation cask.