Sorption of Cs and Eu ions onto sedimentary rock in the presence of gamma-irradiated humic acid

Zhao, Q.*; Saito, Takeshi*; Miyakawa, Kazuya; Sasamoto, Hiroshi; Kobayashi, Taishi*; Sasaki, Takayuki*

Journal of Hazardous Materials, 428, p.128211_1 - 128211_10, 2022/04

https://doi.org/10.1016/j.jhazmat.2021.128211

The influence of humic acid and its radiological degradation on the sorption of Cs and Eu by sedimentary rock was investigated to understand the sorption process of metal ions and humic substances. Aldrich humic acid (HA) solution was irradiated with different doses of gamma irradiation using a Co-60 gamma-ray source prior to the contact between the metal ions and the solid sorbent. The HA molecule decomposed to smaller molecules with a lower complexation affinity. Batch sorption experiments were performed to evaluate the effect of gamma-irradiated HA on the sorption of Cs and Eu ions. The addition of non-irradiated HA weakened the sorption of Eu because of the lower sorption of the neutral or negatively charged Eu-HA complexes compared with free Eu ions. The sorption of monovalent Cs ions was barely affected by the presence of HA and its gamma irradiation. The concentration ratio of HA complexed species and non-complexed species in the solid and liquid phases was evaluated by sequential filtration and chemical equilibrium calculations. The ratios supported the minimal contribution of HA to Cs sorption. However, the concentration ratio for Eu in the liquid phase was high, indicating that the complexing ability of HA to Eu was higher than that of HA to Cs ions. Therefore, the sorption of free Eu would predominate with the gamma irradiation dose applied to the HA solution under a radiation field near the HLW package.

Relation between biomolecular dissociation and energy of secondary electrons generated in liquid water by fast heavy ions

Tsuchida, Hidetsugu*; Kai, Takeshi; Kitajima, Kensei*; Matsuya, Yusuke; Majima, Takuya*; Saito, Manabu*

European Physical Journal D, 74(10), p.212_1 - 212_7, 2020/10

https://doi.org/10.1140/epjd/e2020-10172-x

Fundamental study of interaction between biomolecules and heavy ions in water is very important to predict an initial stage of radiation biological effects. A heavy ion irradiation experiment into droplet target assumed as a biological system in a vacuum was performed to measure production yields of cations and anions for glycine, which was ejected from the droplet target to the vacuum. However, the production mechanisms have been unknown. The PHITS code adapting ion track structure mode was used to analyze the production mechanisms from the dose evaluation at the surface between the vacuum and the water. It is found that induction yields of ionization and excitation, and dissociative electron attachment involved in the secondary electrons were correlated with the production yields of cations and anions of the glycine. The results provide us newly scientific insights to predict an initial stage of radiation biological effects.

Comprehensive evaluation system for environmental remediation of Fukushima; Toward integration of three components as a whole system

Saito, Hiroshi; Nozawa, Takashi; Takemiya, Hiroshi; Seki, Akiyuki; Matsubara, Takeshi; Saito, Kimiaki; Kitamura, Akihiro

JAEA-Review 2017-040, 34 Pages, 2018/03

JAEA-Review-2017-040.pdf:9.52MB

The accidents at Fukushima Daiichi Nuclear Power Station on March 11th 2011, released significant amount of radionuclide to the environment. It has migrated to the human habitation and raised concerns of possible effect on human health, and for that a lot of researches have been performed. JAEA created and opened "Database for Radioactive Substance Monitoring Data" for usage of obtained data. For accurate modelling and future forecast using numerical code and the data, "Supporting Environment for Processing Simulation Codes" has been operated. In addition, research results have been opened as Q&A style "Knowledge Base for Environmental Remediation" in JAEA's website. The "Comprehensive Evaluation System" composed of these components, should act more interrelated and integrated as one system. Besides, information dissemination is not enough to the outside. The report summarizes the current status, remaining issues and expected improvement of each component and the system.

Observation of inverse spin Hall effect in ferromagnetic FePt alloys using spin Seebeck effect

Seki, Takeshi*; Uchida, Kenichi*; Kikkawa, Takashi*; Qiu, Z.*; Saito, Eiji; Takanashi, Koki*

Applied Physics Letters, 107(9), p.092401_1 - 092401_4, 2015/08

https://doi.org/10.1063/1.4929691

Annual report of Nuclear Emergency Assistance and Training Center (April 1, 2013 - March 31, 2014)

Sato, Takeshi; Muto, Shigeo; Akiyama, Kiyomitsu; Aoki, Kazufumi; Okamoto, Akiko; Kawakami, Takeshi; Kume, Nobuhide; Nakanishi, Chika; Koie, Masahiro; Kawamata, Hiroyuki; et al.

JAEA-Review 2014-048, 69 Pages, 2015/02

JAEA-Review-2014-048.pdf:13.91MB

JAEA was assigned as a designated public institution under the Disaster Countermeasures Basic Act and under the Armed Attack Situations Response Act. Based on these Acts, the JAEA has the responsibility of providing technical support to the national government and/or local governments in case of disaster responses or response in the event of a military attack, etc. In order to fulfill the tasks, the JAEA has established the Emergency Action Plan and the Civil Protection Action Plan. In case of a nuclear emergency, NEAT dispatches specialists of JAEA, supplies the national government and local governments with emergency equipment and materials, and gives technical advice and information. In normal time, NEAT provides various exercises and training courses concerning nuclear disaster prevention to those personnel taking an active part in emergency response institutions of the national and local governments, police, fire fighters, self-defense forces, etc. in addition to the JAEA itself. The NEAT also researches nuclear disaster preparedness and response, and cooperates with international organizations. In the FY2013, the NEAT accomplished the following tasks: (1) Technical support activities as a designated public institution in cooperation with the national and local governments, etc. (2) Human resource development, exercise and training of nuclear emergency response personnel for the national and local governments, etc. (3) Researches on nuclear disaster preparedness and response, and sending useful information (4) International contributions to Asian countries on nuclear disaster preparedness and response in collaboration with the international organizations

Spatial distributions of radionuclides deposited onto ground soil around the Fukushima Dai-ichi Nuclear Power Plant and their temporal change until December 2012

Mikami, Satoshi; Maeyama, Takeshi*; Hoshide, Yoshifumi*; Sakamoto, Ryuichi*; Sato, Shoji*; Okuda, Naotoshi*; Demongeot, S.*; Gurriaran, R.*; Uwamino, Yoshitomo*; Kato, Hiroaki*; et al.

Journal of Environmental Radioactivity, 139, p.320 - 343, 2015/01

https://doi.org/10.1016/j.jenvrad.2014.09.010

Current-induced spin polarization on metal surfaces probed by spin-polarized positron beam

Zhang, H.; Yamamoto, Shunya; Fukaya, Yuki; Maekawa, Masaki; Li, H.; Kawasuso, Atsuo; Seki, Takeshi*; Saito, Eiji*; Takanashi, Koki*

Scientific Reports (Internet), 4, p.4844_1 - 4844_5, 2014/04

https://doi.org/10.1038/srep04844

Development of Self Powered Gamma Detector (SPGD) with lead emitter

Shibata, Akira; Takeuchi, Tomoaki; Otsuka, Noriaki; Saito, Takashi; Onoda, Shinobu; Oshima, Takeshi; Tsuchiya, Kunihiko

JAEA-Technology 2013-043, 24 Pages, 2014/01

JAEA-Technology-2013-043.pdf:2.76MB

The big tsunami wave caused by the Great East Japan Earthquake triggered station black out of the Fukushima Daiichi Nuclear Power Plant. The schedule until ending of the decommission is shown in the guidance from Japanese government. But the dose rate in the reactor vessel is quite high and it is not possible to specify the position of melted fuel debris by visual inspection. That is one of the most important issues in this process. This report describes the development of Self Powered Gamma Detector (SPGD) for the purpose to specify the position of melted fuel debris and situation in the reactor by measuring rate in the reactor of the Fukushima Daiichi Nuclear Power Plant. The irradiation examinations by changing the parameter of emitters figure were performed and the dependency of SPGD output on emitter shape was summarized.

Effect of oxygen partial pressure on the viscosity of iron-bearing alkaline-earth silicate slags

Sukenaga, Sohei*; Osugi, Takeshi; Inatomi, Yosuke*; Saito, Noritaka*; Nakashima, Kunihiko*

Journal of MMIJ, 129(5), p.203 - 207, 2013/05

https://doi.org/10.2473/journalofmmij.129.203

Viscosity changes of RO-SiO-FexO (R = Ca, Sr, Ba) melts due to changes in the oxidation states of the iron ions by systematically varying the oxygen partial pressure were measured at 1773 K. The initial compositions of the samples were 30RO-60SiO-10FeO(mol%), and the ratio of Fe toFe in the RO-SiO-FexO melts increased with increasing oxygen partial pressure in all samples. Meanwhile, the viscosity of all the RO-SiO-FexO melts decreased with increasing Fe to total-Fe ratio (Fe/t-Fe). The data indicate that the increase in the amount of Fe ions, which behave as network modifiers, would result in depolymerization of the silicate anions. In addition, the viscosity of the melts increased in the order of alkaline-earth cationic radius (Ba Sr Ca) when the Fe/t-Fe values of the melts were comparable. This would be due to the change in the coordination structure of Fe in the melts.

Design, fabrication and transportation of Si rotating device

Kimura, Nobuaki; Imaizumi, Tomomi; Takemoto, Noriyuki; Tanimoto, Masataka; Saito, Takashi; Hori, Naohiko; Tsuchiya, Kunihiko; Romanova, N. K.*; Gizatulin, S.*; Martyushov, A.*; et al.

JAEA-Technology 2012-012, 34 Pages, 2012/06

JAEA-Technology-2012-012.pdf:12.91MB

Si semiconductor production by Neutron Transmutation Doping (NTD) method using the Japan Materials Testing Reactor (JMTR) has been investigated in Neutron Irradiation and Testing Reactor Center, Japan Atomic Energy Agency (JAEA) in order to expand industry use. As a part of investigations, irradiation test of silicon ingot for development of NTD-Si with high quality was planned using WWR-K in Institute of Nuclear Physics (INP), National Nuclear Center of Republic of Kazakhstan (NNC-RK) based on one of specific topics of cooperation (STC), Irradiation Technology for NTD-Si (STC No.II-4), on the implementing arrangement between NNC-RK and the JAEA for "Nuclear Technology on Testing/Research Reactors" in cooperation in research and development in nuclear energy and technology. As for the irradiation test, Si rotating device was fabricated in JAEA, and the fabricated device was transported with irradiation specimens from JAEA to INP-NNC-RK. This report described the design, the fabrication, the performance test of the Si rotating device and transportation procedures.