Effective use of uranium resources; Communicate the power of a closed cycle

Sagayama, Yutaka; Sawada, Tetsuo*; Tanaka, Harukuni*

Enerugi Foramu, (807), p.18 - 22, 2022/03

Discussing the necessity of the nuclear fuel cycle, its future, and issues (costs, pros and cons of the LWR cycle, etc.). The trend toward carbon neutrality will lead to a rush to build nuclear (light water reactor) power plants in many countries. As a result, the price of natural uranium is expected to skyrocket, increasing the need for fast reactor cycle development. It is essential to present to the world the concept of commercialization of fast reactors that combine high safety and economic efficiency, and to proceed with development steadily in order to realize it promptly, without dissipating the technologies for design, construction, operation, and maintenance of fast reactors that Japanese industry and JAEA have accumulated through the development of MONJU and other projects.

Improvement of HI concentration performance for hydrogen production iodine-sulfur process using crosslinked cation-exchange membrane

Tanaka, Nobuyuki; Sawada, Shinichi*; Yamaki, Tetsuya*; Kodaira, Takahide*; Kimura, Takehiro*; Nomura, Mikihiro*

Chemical Engineering Science, 237, p.116575_1 - 116575_11, 2021/06

https://doi.org/10.1016/j.ces.2021.116575

We have been developing the ion exchange membranes by a radiation grafted polymerization method to improve HI concentration performance for Electro-electrodialysis (EED) in the thermochemical water-splitting hydrogen production iodine-sulfur process. In this work, the crosslinking structures were introduced to the ion exchange membranes. The proton conductivity (), transport number (t), and water permeation factor () of these crosslinked ion exchange membranes were measured and the effect of crosslinks to these performance indexes were investigated. The introduction of crosslinks was found to improve the selectivity of H and water transport (increase of t and decrease of ), although the somewhat decreased. The EED model that we established to discuss the permeation mechanism of EED system was used to theoretically analyze the effect of crosslink on the performance indexes. Based on this analysis of measurement results, the introduction of the crosslink was found to little affect the absorbed amount of HIx solution and H diffusion coefficient in the tested membranes, whereas it could lead to decrease I diffusion coefficient. The results of and t could reflect these effects. In addition, we found the fact that crosslink can inhibit the swelling due to the absorption of the HIx solution. As a result, the value decreased owing to the introduction of crosslink.

An Experimental setup for creating and imaging He excimer cluster tracers in superfluid helium-4 via neutron-He absorption reaction

Sonnenschein, V.*; Tsuji, Yoshiyuki*; Kokuryu, Shoma*; Kubo, Wataru*; Suzuki, So*; Tomita, Hideki*; Kiyanagi, Yoshiaki*; Iguchi, Tetsuo*; Matsushita, Taku*; Wada, Nobuo*; et al.

Review of Scientific Instruments, 91(3), p.033318_1 - 033318_12, 2020/03

https://doi.org/10.1063/1.5130919

Conceptual study on parasitic low-energy RI beam production with in-flight separator BigRIPS and the first stopping examination for high-energy RI beams in the parasitic gas cell

Sonoda, Tetsu*; Katayama, Ichiro*; Wada, Michiharu*; Iimura, Hideki; Sonnenschein, V.*; Iimura, Shun*; Takamine, Aiko*; Rosenbusch, M.*; Kojima, Takao*; Ahn, D. S.*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2019(11), p.113D02_1 - 113D02_12, 2019/11

AA2019-0315.pdf:1.37MB

https://doi.org/10.1093/ptep/ptz120

An in-flight separator, BigRIPS, at RIBF in RIKEN provides each experiment with specific nuclides separated from many nuclides produced by projectile fragmentation or in-flight fission. In this process, nuclides other than separated ones are discarded on the slits in BigRIPS, although they include many nuclides interested from the view point of nuclear structure. In order to extract these nuclides for parasitic experiments, we are developing a method using laser ion-source (PALIS). A test experiment with Se beam from RIBF has been performed by using a gas cell set in BigRIPS. Unstable nuclides around Se were stopped in the gas cell in accordance with a calculation using LISE code. The stopping efficiency has been estimated to be about 30%. As a next step, we will establish the technique for extracting reaction products from the gas cell.

Development of cation and anion exchange membranes for saline water concentration using high-energy heavy-ion beams

Sawada, Shinichi*; Yasukawa, Masahiro*; Koshikawa, Hiroshi*; Kitamura, Akane; Higa, Mitsuru*; Yamaki, Tetsuya*

Nihon Kaisui Gakkai-Shi, 73(4), p.208 - 216, 2019/08

For applications to saline water concentration by electrodialysis, we prepared nano-structure-controlled cation and anion exchange membranes (CEMs and AEMs) by a so-called ion-track grafting technique. This new technique involves irradiation of a polymer substrate with an MeV-GeV heavy-ion beam to form the nano-sized cylindrical ion tracks and the graft polymerization only into the ion tracks for the creation of one-dimensional transport pathways. A 25-m-thick poly(ethylene-co-tetrafluoroethylene) film was irradiated with 560 MeV Xe or 310 MeV Kr. The irradiated films were immersed in grafting solutions of ethyl p-styrenesulfonate (EtSS) and chloromethylstyrene (CMS), and then subjected to the hydrolysis of EtSS units and quaternization of CMS units to prepare CEMs and AEMs, respectively. These CEMs and AEMs showed lower resistance than the commercially-available membranes even at the very low water uptake. This would be due to the signifcantly-effcient transport of ions through the unique one-dimensional highly-connected transport pathways. In the saline water concentration experiment, a pair of our CEM and a commercial AEM or vice versa led to a higher salt concentration in the concentration chamber than did a pair of the commercial membranes. This result demonstrated great applicability of our ion-track-grafted CEMs and AEMs for saline water concentration.

Generation of He clusters via neutron-He absorption reaction toward visualization of full velocity field in quantum turbulence

Matsushita, Taku*; Sonnenschein, V.*; Guo, W.*; Hayashida, Hirotoshi*; Hiroi, Kosuke; Hirota, Katsuya*; Iguchi, Tetsuo*; Ito, Daisuke*; Kitaguchi, Masaaki*; Kiyanagi, Yoshiaki*; et al.

Journal of Low Temperature Physics, 196(1-2), p.275 - 282, 2019/07

https://doi.org/10.1007/s10909-018-02112-3

Development of ion-exchange membranes for the membrane Bunsen reaction in thermochemical hydrogen production by iodine-sulfur process

Nomura, Mikihiro*; Kodaira, Takahide*; Ikeda, Ayumi*; Naka, Yasuhito*; Nishijima, Haruyuki*; Imabayashi, Shinichiro*; Sawada, Shinichi*; Yamaki, Tetsuya*; Tanaka, Nobuyuki; Kubo, Shinji

Journal of Chemical Engineering of Japan, 51(9), p.726 - 731, 2018/09

https://doi.org/10.1252/jcej.17we183

Thermochemical hydrogen production by the iodine-sulfur process decomposes water into hydrogen and oxygen by combining the chemical reactions of iodine and sulfur. Two types of acids are produced through the Bunsen reaction. To improve the performance of this reaction, ion-exchange membranes for the membrane Bunsen reaction should be developed. In the present study, a cation-exchange membrane was prepared by using a radiation-graft polymerization method. It was found that a divinylbenzene crosslinking procedure was very effective in reducing water permeation through the membrane, and the membrane Bunsen reaction was successfully carried out by using the developed crosslinked membrane. Therefore, the developed crosslinked membrane is a potential candidate for cation-exchange membranes for the membrane Bunsen reaction.

Research on nanostructure-controlled functional membranes using high-energy ion beams; Fluoropolymer-based porous and ion-exchange membranes

Yamaki, Tetsuya*; Kitamura, Akane; Sawada, Shinichi*; Koshikawa, Hiroshi*

Nihon Kaisui Gakkai-Shi, 72(2), p.62 - 74, 2018/04

This review paper is devoted to two topics, i.e., fluoropolymer-based porous and ion-exchange membranes, both of which include the creation of nanostructure-controlled functional membranes with high-energy ion beams. Latent tracks of the MeV-GeV heavy ions in a polymer foil can sometimes be chemically etched out to form a membrane with micro- and nano-sized through-pores, the so-called ion-track membrane. Our focus is on ion-track membranes of poly (vinylidene fluoride) (PVDF) and cation- and anion-exchange membranes (CEMs and AEMs, respectively).

Chemical form analysis of reaction products in Cs-adsorption on stainless steel by means of HAXPES and SEM/EDX

Kobata, Masaaki; Okane, Tetsuo; Nakajima, Kunihisa; Suzuki, Eriko; Owada, Kenji; Kobayashi, Keisuke*; Yamagami, Hiroshi; Osaka, Masahiko

Journal of Nuclear Materials, 498, p.387 - 394, 2018/01

https://doi.org/10.1016/j.jnucmat.2017.10.035

In this study, for the understandings of Cesium (Cs) adsorption behavior on structure materials in severe accidents at a light water nuclear reactor, the chemical state of Cs and its distribution on the surface of SUS304 stainless steel (SS) with different Si concentration were investigated by hard X-ray photoelectron spectroscopy (HAXPES) and scanning electron microscope / energy dispersive X-ray spectroscopy (SEM/EDX). As a result, it was found that Cs is selectively adsorbed at the site where Si distributes with high concentration. CsFeSiO is a dominant Cs products in the case of low Si content, mainly formed, while CsSiO and CsSiO are formed in addition to CsFeSiO in the case of high Si content. The chemical forms of the Cs compounds produced in the adsorption process on the SS surface has a close correlation with the concentration and chemical states of Si originally included in SS.

Rock mass property evaluation based on the borehole wall images taken by using an ultrasonic scanner (USS)

Otsuka, Yasunori*; Ishikawa, Takanori*; Tajima, Katsuhiro*; Wada, Tetsu*; Aydan, mer*; Tokashiki, Naohiko*; Sato, Toshinori; Aoyagi, Kazuhei

Journal of Nepal Geological Society, 55(Special Issue), p.1 - 6, 2018/00

Ultrasonic wave reflection intensity of the wall of borehole drilled from bottom of the East Access Shaft in the Horonobe Underground Research Laboratory, Hokkaido, Japan, was obtained using an ultrasonic scanner (USS). In this paper, we compared results of USS observation with core logging data including core observation, optical digital scanner (ODS) observation, and result of Needle Penetration Index (NPI) tests. The results indicated that ultrasonic wave reflection intensity had a good correlation with other observation results. USS observation and NPI tests are useful techniques for determination of detailed rock mass classification.