Matsuoka, Amane; Yasumune, Takashi; Kojima, Nobuhiro; Miyauchi, Hideaki; Takasaki, Koji; Hashimoto, Makoto
JAEA-Review 2021-055, 11 Pages, 2021/12
The dose limit for the eye lens was lowered on April 1 2021, and a 3 mm dose equivalent was added to the calculation. The guidelines require that lens dosimeters be worn and managed when there is a risk of exceeding control standards. In this report, in order to examine future management methods, we investigated whether work that might exceed the equivalent dose limit was performed in the past. As a result of the investigation, the exposure dose for all works after fiscal year 2008 was sufficiently low compared to the equivalent dose limit. For this reason, it is considered that there is no need for additional management of wearing a personal dosimeter near the eyes for the work that is normally performed. In the future, as in the past, the basic management method will be to wear a dosimeter only on the basic part of the trunk under uniform exposure conditions, and to wear a dosimeter on the basic part of the trunk and the maximum dose part under nonuniform exposure conditions. When performing work with a high exposure dose to the eye lens, a dosimeter should be worn near the eye to measure the 3 mm dose equivalent.
Aoki, Sinya*; Aoki, Yasumichi*; Cossu, G.*; Fukaya, Hidenori*; Hashimoto, Shoji*; Kaneko, Takashi*; Rohrhofer, C.*; Suzuki, Kei
Physical Review D, 103(7), p.074506_1 - 074506_18, 2021/04
We investigate the axial anomaly of two-flavor QCD at temperatures 190-330 MeV. In order to preserve precise chiral symmetry on the lattice, we employ the Mbius domain-wall fermion action as well as overlap fermion action implemented with a stochastic reweighting technique. Compared to our previous studies, we reduce the lattice spacing to 0.07 fm, simulate larger multiple volumes to estimate finite size effect, and take more than four quark mass points, including one below physical point to investigate the chiral limit. We measure the topological susceptibility, axial susceptibility, and examine the degeneracy of partners in meson/baryon correlators. All the data above the critical temperature indicate that the axial violation is consistent with zero within statistical errors. The quark mass dependence suggests disappearance of the anomaly at a rate comparable to that of the symmetry breaking.
Hashimoto, Makoto; Kinase, Sakae; Munakata, Masahiro; Murayama, Takashi; Takahashi, Masa; Takada, Chie; Okamoto, Akiko; Hayakawa, Tsuyoshi; Sukegawa, Masato; Kume, Nobuhide*; et al.
JAEA-Review 2020-071, 53 Pages, 2021/03
In the case of a nuclear accident or a radiological emergency, the Japan Atomic Energy Agency (JAEA), as a designated public corporation assigned in the Disaster Countermeasures Basic Act and the Armed Attack Situation Response Law, undertakes technical supports to the national government and local governments. The JAEA is requested to support to evaluate radiation doses to residents in a nuclear emergency, which is specified in the Basic Disaster Management Plan and the Nuclear Emergency Response Manual. For the dose evaluation, however, its strategy, target, method, structure and so on have not been determined either specifically or in detail. This report describes the results of investigation and consideration discussed in the "Working Group for Radiation Dose Evaluation at a Nuclear Emergency" established within the Nuclear Emergency Assistance and Training Center to discuss technical supports for radiation dose evaluation to residents in the case of a nuclear emergency, and aims at contributing to specific and detailed discussion and activities in the future for the national government and local governments, also within the JAEA.
Watanabe, Hiroshi*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Andreyev, A. N.; Hashimoto, Takashi*; Kondev, F. G.*; Lane, G. J.*; Litvinov, Yu. A.*; Liu, J. J.*; Miyatake, Hiroari*; et al.
Physics Letters B, 814, p.136088_1 - 136088_6, 2021/03
Taruta, Yasuyoshi; Yanagihara, Satoshi*; Hashimoto, Takashi*; Kobayashi, Shigeto*; Iguchi, Yukihiro; Kitamura, Koichi; Koda, Yuya; Tomoda, Koichi
Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 8 Pages, 2020/08
Decommissioning is a long-term project during which generations are expected to change. Therefore, it is necessary to appropriately transfer knowledge and technology to the next generation. In recent years, in the world of decommissioning, attempts have been made to apply advanced technologies such as utilization of knowledge management and virtual reality. This study describes adaptation in decommissioning from the viewpoint of utilizing IT technology called digital twin from the viewpoint of knowledge management.
Nakazato, Seiya*; Iwasa, Kazuaki*; Hashimoto, Daisuke*; Shiozawa, Mami*; Kuwahara, Keitaro*; Nakao, Hironori*; Sagayama, Hajime*; Ishikado, Motoyuki*; Ohara, Takashi; Nakao, Akiko*; et al.
JPS Conference Proceedings (Internet), 30, p.011128_1 - 011128_6, 2020/03
Zhao, Q.*; Taruta, Yasuyoshi; Kobayashi, Shigeto*; Hashimoto, Takashi*
Chishiki Kyoso (Internet), 9, p.III 1_1 - III 1_9, 2019/06
no abstracts in English
Takasaki, Koji; Yasumune, Takashi; Hashimoto, Makoto; Maeda, Koji; Kato, Masato; Yoshizawa, Michio; Momose, Takumaro
JAEA-Review 2019-003, 48 Pages, 2019/03
June 6, 2017, at Plutonium Fuel Research Facility in Oarai Research and Development Center of JAEA, when five workers were inspecting storage containers containing plutonium and uranium, resin bags in a storage container ruptured, and radioactive dust spread. Though they were wearing a half face mask respirator, they inhaled radioactive materials. In the evaluation of the internal exposure dose, the aerodynamic radioactive median diameter (AMAD) is an important parameter. We measured 14 smear samples and a dust filter paper with imaging plates, and estimated the AMAD by image analysis. As a result of estimating the AMAD, from the 14 smear samples, the AMADs are 4.3 to 11 m or more in the case of nitrate plutonium, and the AMADs are 5.6 to 14 m or more in the case of the oxidized plutonium. Also, from the dust filter paper, the AMAD is 3.0 m or more in the case of nitrate plutonium, and the AMAD is 3.9 m or more in the case of the oxidized plutonium.
Zhao, Q.*; Taruta, Yasuyoshi; Kobayashi, Shigeto*; Hashimoto, Takashi*
Chishiki Kyoso (Internet), 8, p.V 13_1 - V 13_2, 2018/08
no abstracts in English
Das, S. K.*; Fukuda, Tomokazu*; Mizoi, Yutaka*; Ishiyama, Hironobu*; Miyatake, Hiroari*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Jeong, S. C.*; Ikezoe, Hiroshi*; Matsuda, Makoto; et al.
Physical Review C, 95(5), p.055805_1 - 055805_4, 2017/05
Makhsun*; Hashimoto, Takuya*; Sakuma, Takashi*; Takahashi, Haruyuki*; Kamishima, Osamu*; Igawa, Naoki; Danilkin, S. A.*
Journal of the Physical Society of Japan, 83(7), p.074602_1 - 074602_4, 2014/07
The correlations of atomic thermal displacements in Al were obtained from the analysis of diffuse neutron scattering intensity. The interatomic force constants were determined from the correlation effects using a newly introduced equation. The derived force constants and the crystal structure of Al were used to estimate the phonon dispersion relations, phonon density of states, and specific heat by computer simulation. The calculated phonon dispersion relations and specific heat of Al are similar to those obtained from inelastic neutron scattering and specific heat measurements, respectively.
Oda, Yasuhisa; Oshima, Katsumi; Nakamoto, Takashi*; Hashimoto, Yasunori*; Yamamoto, Tsuyoshi; Hayashi, Kazuo*; Ikeda, Yukiharu; Ikeda, Ryosuke; Kajiwara, Ken; Takahashi, Koji; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 90(7), p.365 - 373, 2014/07
no abstracts in English
Nagai, Yasuki; Hashimoto, Kazuyuki; Hatsukawa, Yuichi; Saeki, Hideya; Motoishi, Shoji; Sonoda, Nozomi; Kawabata, Masako; Harada, Hideo; Kin, Tadahiro*; Tsukada, Kazuaki; et al.
Journal of the Physical Society of Japan, 82(6), p.064201_1 - 064201_7, 2013/06
Oi, Motoki; Teshigawara, Makoto; Kai, Tetsuya; Harada, Masahide; Maekawa, Fujio; Futakawa, Masatoshi; Hashimoto, Eiko*; Segawa, Mariko; Kureta, Masatoshi; Tremsin, A.*; et al.
Physics Procedia, 43, p.337 - 342, 2013/04
The Japan Spallation Neutron Source (JSNS) at the Japan Proton Accelerator Research Complex (J-PARC) had been developed as a 1-MW spallation neutron source. A Au-In-Cd alloy has been proposed as a new decoupler material. Recently, we successfully produced the ternary Au-In-Cd alloy. The alloy composition is 74.9 at% Au, 0.5 at% In, and 24.6 at% Cd. We used the pulsed neutron imaging techniques to measure the elements in the Au-In-Cd alloy. Both a time gated camera system and a multi-channel plate (MCP) detector were used as detectors. Measurement was performed at BL10 in the JSNS. A Au-In-Cd specimen, In foil and two Au foils are used as a sample. As a results, we could obtain distribution of Au, In and Cd in the Au-In-Cd specimens distinctly.
Hirayama, Yoshikazu*; Mihara, Mototsugu*; Watanabe, Yutaka*; Jeong, S. C.*; Miyatake, Hiroari*; Momota, Sadao*; Hashimoto, Takashi*; Imai, Nobuaki*; Matsuta, Kensaku*; Ishiyama, Hironobu*; et al.
European Physical Journal A, 48(5), p.54_1 - 54_10, 2012/05
Horikawa, Daiki*; Yamaguchi, Ayami*; Sakashita, Tetsuya; Tanaka, Daisuke*; Hamada, Nobuyuki*; Yukuhiro, Fumiko*; Kuwahara, Hirokazu*; Kunieda, Takekazu*; Watanabe, Masahiko*; Nakahara, Yuichi*; et al.
Astrobiology, 12(4), p.283 - 289, 2012/04
We examined the hatchability of hydrated and anhydrobiotic eggs of the tardigrade to hatch after ionizing irradiation (helium ions), extremely low and high temperatures, and high vacuum. Anhydrobiotic eggs (50% lethal dose; 1690 Gy) were substantially more radioresistant than hydrated ones (50% lethal dose; 509 Gy). Anhydrobiotic eggs also have a broader temperature resistance compared with hydrated ones. Over 70% of the anhydrobiotic eggs treated at high and low temperatures, but all of the hydrated eggs failed to hatch. After exposure to high vacuum conditions, the hatchability of the anhydrobiotic eggs was comparable to that of untreated control eggs.
Ishiyama, Hironobu*; Yamaguchi, Kanako*; Mizoi, Yutaka*; Watanabe, Yutaka*; Das, S. K.*; Hashimoto, Takashi*; Miyatake, Hiroari*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Oyaizu, Mitsuhiro*; et al.
Journal of Instrumentation (Internet), 7(3), p.C03036_1 - C03036_14, 2012/03
We developed an active-target type gas counter operating with low He/CO (10%) detector gas for application in studying low-energy nuclear reactions using radioactive beams. A 400-m-thick gas electron multiplier (THGEM) was used as the proportional counter for high injection rate capability. We examined the gas gain stability and the influence of ion feedback on particle tracks at high beam injection rates of up to 10 particles per second (pps) using a low-energy C beam. From the result of this examination, we found that the THGEM was found to be applicable for our active target at high injection rates of up to 10 pps.
Nagai, Yasuki; Hatsukawa, Yuichi; Kin, Tadahiro; Hashimoto, Kazuyuki; Motoishi, Shoji; Konno, Chikara; Ochiai, Kentaro; Takakura, Kosuke; Sato, Yuichi*; Kawauchi, Yukimasa*; et al.
Journal of the Physical Society of Japan, 80(8), p.083201_1 - 083201_4, 2011/08
We have for the first time succeeded to separate Tc from a Mo oxide sample irradiated by accelerator neutrons, and to formulate Tc-methylene diphosphonate (Tc-MDP). Mo, the mother nuclide of Tc, was produced by the Mo(,2)Mo reaction using about 14 MeV neutrons provided at the Fusion Neutronics Source of Japan Atomic Energy Agency. The Tc was separated from Mo by the sublimation method, and its radionuclide purity was confirmed to be higher than 99.99%. The labeling efficiency of Tc-MDP was shown to be higher than 99%. These values exceed the United States Pharmacopeia requirements for a fission product, Mo. Consequently, a Tc radiopharmaceutical preparation formed by using the mentioned Mo can be a promising substitute for the fission product Mo. A longstanding problem to ensure a reliable and constant supply of Mo in Japan can be partially mitigated.
Setoodehnia, K.*; Chen, A. A.*; Komatsubara, Tetsuro*; Kubono, Shigeru*; Binh, D. N.*; Carpino, J. F.*; Chen, J.*; Hashimoto, Takashi*; Hayakawa, Takehito; Ishibashi, Yoko*; et al.
Physical Review C, 83(1), p.018803_1 - 018803_4, 2011/01
The structure of proton-unbound S states strongly determines the thermonuclear P(, )S reaction rate at temperatures characteristic of explosive hydrogen burning in classical novae and type I X-ray bursts. Specifically, the rate had been previously predicted to be dominated by two low-lying, unobserved, levels in the =4.7-4.8 MeV region, with spin and parity assignments of 3 and 2. In recent experimental work, two candidate levels were observed with energies of 4.699 MeV and 4.814 MeV, but no experimental information on their spins and parities was obtained. We have performed an in-beam -ray spectroscopy study of S with the Si(He, )S reaction. The spin and parities were inferred from a comparison to the known decay schemes of the corresponding mirror states.
Hashimoto, Takashi; Ishiyama, Hironobu*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Miyatake, Hiroari; Jeong, S.-C.*; Tanaka, Masahiko*; Yoshikawa, Nobuharu*; Nomura, Toru*; et al.
Physics Letters B, 674(4-5), p.276 - 280, 2009/04
The excitation function of the Li(d,t)Li reaction was directly measured using Li beams at E = 0.3, 0.4, 0.5, 0.7, 0.8, 1.0, 1.1, and 1.2 MeV with CD targets. The beam energies covered the Gamow peaks for 1310 K. Large cross sections were observed at around E = 0.8 MeV, implying a resonance state located at 22.4 MeV in Be. The present astrophysical reaction rate is higher in one order magnitude than the presently adopted rate at around 110 K.