Efficient hydrogen isotope separation by tunneling effect using graphene-based heterogeneous electrocatalysts in electrochemical hydrogen isotope pumping

Yasuda, Satoshi; Matsushima, Hisayoshi*; Harada, Kenji*; Tanii, Risako*; Terasawa, Tomoo; Yano, Masahiro; Asaoka, Hidehito; Gueriba, J. S.*; Dio, W. A.*; Fukutani, Katsuyuki

ACS Nano, 16(9), p.14362 - 14369, 2022/09

https://doi.org/10.1021/acsnano.2c04655

The fabrication of hydrogen isotope enrichment system is essential for the development of industrial, medical, life science, and nuclear fusion fields, therefore alternative enrichment techniques with high separation factor and economic feasibility have been still explored. Herein, we report the fabrication of heterogeneous electrode with layered structures consisting of palladium and graphene layers for polymer electrolyte membrane electrochemical hydrogen pumping for the hydrogen isotope enrichment. We demonstrated significant bias voltage dependence of hydrogen/deuterium (H/D) separation ability and its high H/D at lower bias voltage. Theoretical analysis also demonstrated that the observed high H/D at low bias voltage stems from hydrogen isotopes tunneling through atomically-thick graphene during the electrochemical reaction, and the bias dependent H/D results in a transition from the quantum tunneling regime to classical over- barrier regime for hydrogen isotopes transfer via the graphene. These findings provide new insight for a novel economical methodology of efficient hydrogen isotope enrichment.

Measurements of the Am neutron capture and total cross sections with ANNRI at J-PARC

Kimura, Atsushi; Nakamura, Shoji; Terada, Kazushi*; Nakao, Taro*; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.

Journal of Nuclear Science and Technology, 56(6), p.479 - 492, 2019/06

https://doi.org/10.1080/00223131.2019.1598508

Cavitation damage in double-walled mercury target vessel

Naoe, Takashi; Wakui, Takashi; Kinoshita, Hidetaka; Kogawa, Hiroyuki; Haga, Katsuhiro; Harada, Masahide; Takada, Hiroshi; Futakawa, Masatoshi

Journal of Nuclear Materials, 506, p.35 - 42, 2018/08

BB2016-1013.pdf:0.96MB

https://doi.org/10.1016/j.jnucmat.2017.10.044

A mercury target vessel made of 316L SS is damaged due to the cavitation caused by the pressure waves in mercury. Cavitation damage reduces the structural integrity of the target front, called "beam window", being major factor to determine the lifetime of target vessel. Aiming at mitigating the cavitation damage by faster mercury flow in narrow channel, we employed a target vessel with a double-walled structure at the beam window along with a gas microbubbles injection. After operating the double-walled target vessel with a beam power of 300 to 500 kW, we cut out the beam window using an annular cutter to examine the damage inside it, and found that damages with maximum pit depth of approximately 25 m distributed in a belt on the specimen facing narrow channel. Furthermore, numerical simulation result showed that the distribution of negative pressure period from beam injection to 1 ms was correlated with the damage distribution in the narrow channel. It was suggested that the cavitation induced by relatively short negative pressure period contributed to the damage formation.

Cutting-edge studies on nuclear data for continuous and emerging need, 2; Nuclear data measurements and theoretical analysis in the resonance region

Kimura, Atsushi; Harada, Hideo; Kunieda, Satoshi; Katabuchi, Tatsuya*

Nihon Genshiryoku Gakkai-Shi ATOMO, 59(11), p.654 - 658, 2017/11

no abstracts in English

High precision analysis of isotopic composition for samples used for nuclear cross-section measurements

Shibahara, Yuji*; Hori, Junichi*; Takamiya, Koichi*; Fujii, Toshiyuki*; Fukutani, Satoshi*; Sano, Tadafumi*; Harada, Hideo

EPJ Web of Conferences, 146, p.03028_1 - 03028_4, 2017/09

https://doi.org/10.1051/epjconf/201714603028

Mitigation technologies for damage induced by pressure waves in high-power mercury spallation neutron sources, 4; Measurement of pressure wave response and microbubble effect on mitigation in mercury target at J-PARC

Kogawa, Hiroyuki; Naoe, Takashi; Futakawa, Masatoshi; Haga, Katsuhiro; Wakui, Takashi; Harada, Masahide; Takada, Hiroshi

Journal of Nuclear Science and Technology, 54(7), p.733 - 741, 2017/07

https://doi.org/10.1080/00223131.2017.1309302

A mercury target system has been operated to produce neutron beams at the spallation neutron source in the Japan Proton Accelerator Research Complex (J-PARC). Pressure waves are generated in mercury by rapid heat generation at the time of high-intensity short-pulse proton beam injection. Not only they cause cyclic stress but also induce the cavitation damage on the target vessel made from type 316L stainless steel. Reduction of these pressure waves is very important issue to ensure enough lifetime of the target vessel. To solve the issue, we have been developing the technique to inject microbubbles into mercury. In this study, we installed a microbubble generator in the mercury target vessel, and investigate the effect of proton beam condition and the microbubbles on the pressure wave mitigation by measuring the displacement velocity of the target vessel with an in-situ diagnostic system. As a result, we observed that the peak displacement velocity of the target vessel decreased down to 1/3 and 2/3 for the injected gas fractions of 0.4% and 0.1%, respectively.

Neutron flux spectrum revealed by Nb-based current-biased kinetic inductance detector with a B conversion layer

Miyajima, Shigeyuki*; Shishido, Hiroaki*; Narukami, Yoshito*; Yoshioka, Naohito*; Fujimaki, Akira*; Hidaka, Mutsuo*; Oikawa, Kenichi; Harada, Masahide; Oku, Takayuki; Arai, Masatoshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 842, p.71 - 75, 2017/01

https://doi.org/10.1016/j.nima.2016.10.045

Characteristics of neutron resonance densitometry, 2; Neutron resonance capture analysis

Tsuchiya, Harufumi; Harada, Hideo; Koizumi, Mitsuo; Kitatani, Fumito; Kureta, Masatoshi; Becker, B.*; Kopecky, S.*; Heyse, J.*; Paradela, C.*; Mondelaers, W.*; et al.

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2015/12

Neutron Resonance Densitometry (NRD) was developed as a non-destructive assay to quantify U and Pu isotopes in particle-like debris. NRD is composed of neutron resonance transmission analysis (NRTA) and Neutron Resonance Capture Analysis (NRCA) or Prompt Gamma-ray Analysis (PGA). NRCA/PGA in NRD plays a role of identifying impurities in debris under the high-radiation field primarily caused by Cs. For this purpose, a novel LaBr -ray detector employing specific shields has been newly developed. With the developed -ray detector, a demonstration NRCA experiment was performed at a neutron time of flight facility GELINA (Belgium). As a result, samples (Hf, Gd, Ni) placed in a black box that is completely sealed by third party were successfully identified by the experiment. This presentation explains the design concept of the ray detector including its detection principle and details of the demonstration NRCA experiment.

Microstructure and residual strain distribution in cast duplex stainless steel studied by neutron imaging

Su, Y. H.; Oikawa, Kenichi; Kawasaki, Takuro; Kai, Tetsuya; Shiota, Yoshinori*; Sato, Hirotaka*; Shinohara, Takenao; Tomota, Yo*; Harada, Masahide; Kiyanagi, Ryoji; et al.

JPS Conference Proceedings (Internet), 8, p.031015_1 - 031015_5, 2015/09

https://doi.org/10.7566/JPSCP.8.031015

In this study, neutron imaging experiment was performed using NOBORU, BL10 of MLF at J-PARC. Four kinds of cast duplex stainless steel with ferrite and austenite microstructure were studied here, which were produced by different casting method at different temperature. Firstly, two-dimensional scintillation detector using wavelength-shifting fibers with pixel size of 0.52 mm 0.52 mm and illuminated area 55 mm 55 mm was used for data collection. Then, measurement by Micro Pixel Chamber based neutron imaging detector having higher spatial resolution about 0.2 mm was conducted. Data analysis code RITS (Rietveld Imaging of Transmission Spectra) will be used for microstructure including crystalline phase, lattice strain, crystallite size, texture evaluation.

Development status of the NMR system for the polarized He Neutron Spin Filter (NSF) in the MLF at J-PARC

Sakai, Kenji; Oku, Takayuki; Hayashida, Hirotoshi*; Kira, Hiroshi*; Hiroi, Kosuke; Ino, Takashi*; Oyama, Kenji*; Okawara, Manabu*; Kakurai, Kazuhisa; Shinohara, Takenao; et al.

JPS Conference Proceedings (Internet), 8, p.036015_1 - 036015_6, 2015/09

https://doi.org/10.7566/JPSCP.8.036015

The polarized He filter, which polarizes neutrons due to a large neutron absorption cross section of He with strong spin selectivity, becomes a convenient neutron spin filter (NSF) because it is operated immediately after its installation in beam lines without any neutron beam adjustments. For realizing such the NSF, a nuclear magnetic resonance (NMR) system is indispensable for monitoring He nuclear spin polarization of the NSF. We have developed the flexible NMR system based on adiabatic fast passage (AFP) and pulse NMR methods by using their complementary features. In comparing with the values of obtained by neutron transmission measurement at the beam line 10 of the J-PARC, we measured the correlations between the AFP and pulse NMR signals as changing condition of temperature, amplitude and applying period of the radio frequency field for the pulse NMR, and so on. As the results, we confirmed that our system would function enough as the monitor.