Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Nakashima, Hiroshi; Nakamura, Takemi; Kobayashi, Hitoshi*; Tanaka, Susumu*; Kumada, Hiroaki*
NEA/NSC/R(2021)2 (Internet), p.142 - 151, 2021/12
Aiming of development of facilities for boron neutron capture therapy (BNCT) that can be installed in hospitals, an accelerator-based BNCT facility is being developed at the Ibaraki Neutron Medical Research Center under a collaboration among the Japan Atomic Energy Agency, the High Energy Accelerator Research Organization, the University of Tsukuba, and other institutions. It consists of a proton accelerator, having a maximum beam power of 80 kW, and a target, moderator, collimator and shield (TMCS) system. For the design concept, to satisfy the BNCT beam conditions and achieve a low activation, the radiation behavior in the TMCS system was simulated by the Monte Carlo method and this system configuration was optimized accordingly. In addition, the radiation estimation of the TMCS system was verified via several experiments and its applicability for BNCT was proved. This report reviews the estimation and validation studies for the development of the accelerator-based BNCT facility.
Tsuji, Masakuni*; Nakashima, Hitoshi*; Saito, Akira*; Okihara, Mitsunobu*; Sato, Toshinori
45th Annual Waste Management Conference (WM 2019); Encouraging Young Men & Women to Achieve Their Goals in Radwaste Management, Vol.7, p.4749 - 4763, 2020/01
A rock excavation grouting technology has been recently studied as significant technology for reducing the ingress of water into the deep repository. However, it has not been studied for applying to the coastal region, where it is discussed to be a more suitable region for the geological disposal in Japan. The latest material called colloidal silica grout (CSG) is good for sealing narrow fractures but is known to be sensitive to the salinity of groundwater because of its gelling property with salt accelerator. Although the gelling of CSG can be controlled by adding an acidic pH adjuster, the methodology for delivering the appropriate grout is not well established for such conditions of saline groundwater. Therefore, this research project was established to enhance the existing rock grouting technology for deep repositories.
Tsuji, Masakuni*; Okihara, Mitsunobu*; Nakashima, Hitoshi*; Saito, Akira*; Aoyagi, Kazuhei; Sato, Toshinori
Dai-47-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (Internet), p.266 - 271, 2020/01
As engineering technique for geological disposal, a lot of advancement development of the grout technology has been performed. But the design, construction method in consideration of the properties of matter acquisition and mechanism of the hardening that assumed a seawater condition bottom is non-establishment. As we carried out the knowledge under saline water, the basic properties acquisition, the penetration properties acquisition, a study revue based on such situation.
Tsuji, Masakuni*; Aoyagi, Kazuhei; Nakashima, Hitoshi*; Okihara, Mitsunobu*; Sato, Toshinori
Proceedings of the Nordic Grouting Symposium 2019 (Internet), 15 Pages, 2019/09
This paper shows an overall result of the 3-year study on the characterisation of the colloidal silica grout (CSG) under saline groundwater, aiming to enhance the existing rock grouting technology, especially for the CSG under the saline groundwater. As a first step, we performed the survey of the latest grouting technology of CSG. We developed a feasible mixing methodology and have obtained the various CSG's properties impacted by the salty mixing water or submerged by saline water. Moreover, we proposed a theory for the grout penetration under saline water and performed the injection tests. In the second workshop in the final year, our overall findings in this study were recognised to attain some progress in the development of the grouting technology.
Martikainen, J.*; Tsuji, Masakuni*; Schatz, T.*; Nakashima, Hitoshi*; Okihara, Mitsunobu*; Aoyagi, Kazuhei; Sato, Toshinori
Proceedings of the Nordic Grouting Symposium 2019 (Internet), 13 Pages, 2019/09
This paper shows a result of the part of the study on characterisation of penetration of the colloidal silica grout (CSG) under saline groundwater, aiming to understand the impact of salinity on grout penetration by verifying the improved penetration theory with laboratory tests. This theory was proposed to add a time factor 
to the existing penetration theory of Funehag, especially under the saline groundwater conditions. A series of grout injection tests by the fracture test system were performed. The CSG of one European and Japanese were injected in the system, filled with the five different groundwater simulants. All no-flow tests were successful, resulting in the formation of relatively homogeneous gelled zones. Based on the analysis of acquired , it was found that as an alternative method, designing a longer gel time by multiplying the inverse value of can be proposed to attain the required penetration. Although the results were fruitful, further investigation is necessary to develop this penetration theory.
Tada, Junichiro*; Nakashima, Hiroshi; Hayano, Ryugo*; Kobayashi, Hitoshi*; Asano, Yoshihiro*
Wakariyasui Hoshasen Butsurigaku; Kaitei 3-Han, 305 Pages, 2018/03
This book is an introduction to radiation physics. Under the concept of "linking physics of high school and radiation physics" for readers with high school graduation degree, we are doing simple commentary on the basis of qualitative explanation as much as possible. This book begins with "What is Radiation Physics", and consists of 12 chapters, including introductory special relativity, introductory quantum theory, structures of atoms and nuclei, radiations, radioactivity, interactions between radiation and matter, accelerators, radiation dose and so on.
Toguri, Satohito*; Okihara, Mitsunobu*; Tsuji, Masakuni*; Nakashima, Hitoshi*; Sugiyama, Hirokazu*; Saito, Akira*; Sato, Toshinori; Aoyagi, Kazuhei; Masunaga, Kosuke
JAEA-Research 2017-013, 131 Pages, 2018/02
JAEA-Research-2017-013.pdf:8.49MB
The discussions on scientifically promising site for the geological disposal has been made at the council of studying group on techniques for geological disposal of radioactive wastes, which is held by Resources and Energy Agency. From the aspect of ensuring safety during the transportation of disposal waste, the coastal area is discussed to be a more suitable area. This report shows the result of the first year of this project as following items; Study on the state-of-art technology and remain tasks; laboratory tests on characterization of colloidal silica grout under sea water; Study on the development of grouting technology (design and the evaluation method of influence on the rock mass).
Tsuji, Masakuni*; Okihara, Mitsunobu*; Nakashima, Hitoshi*; Sato, Toshinori; Aoyagi, Kazuhei
Proceedings of 6th East Asia Forum on Radwaste Management Conference (EAFORM 2017) (Internet), 6 Pages, 2017/12
Regarding the engineering technology, the rock grouting has been recently studied as one of the most important technologies. Although the cement grout has not been reported to be affected by the sea water, the latest grouting material called colloidal silica grout is known to be sensitive to the saline water. The mechanism of its affection by sea water is not clear and its grouting methodology in such condition is not yet established either. Therefore, we studied on the latest grouting technologies for geological disposal in Nordic countries and Japan by article survey and a grouting workshop. As a result, it was found that the approach for countermeasures in grouting under sea water is different between Japan, Sweden, and Finland, which are based respectively on the mixture, on the design method, and on the controlling method. It seems that the best solution against this problem is to establish a hybrid and optimal grouting methodology under sea water by combining each country's developed grouting technology in the near future for saline condition, which is respectively based on mixing, design, and controlling method.
Tasaka, Kanji; Katakura, Junichi; Ihara, Hitoshi; Yoshida, Tadashi*; Iijima, Shungo*; Nakashima, Ryuzo*; Nakagawa, Tsuneo; Takano, Hideki
JAERI 1320, 253 Pages, 1990/09
no abstracts in English
Haraga, Tomoko; Katayama, Atsushi; Kameo, Yutaka; Nakashima, Mikio; Hoshino, Hitoshi*
no journal, ,
For the safe disposal of low-level radioactive wastes, it is indispensable to evaluate radioactivity concentration in each waste package. In order to simplify the radiochemical analysis of Eu and Ho in radioactive waste samples, applicability of capillary electrophoresis was examined. After pre-capillary complexation with aromatic polyaminocarboxylate, on-capillary complexation method using various auxiliary reagents was examined. It was found that the addition of iminodiacetic acid to the electrolyte was effective for separation of Eu and Ho from matrix elements, Al, Fe, Ca, Na.
Haraga, Tomoko; Katayama, Atsushi; Kameo, Yutaka; Nakashima, Mikio; Hoshino, Hitoshi*
no journal, ,
no abstracts in English
Haraga, Tomoko; Katayama, Atsushi; Kameo, Yutaka; Nakashima, Mikio; Hoshino, Hitoshi*
no journal, ,
no abstracts in English
Haraga, Tomoko; Kameo, Yutaka; Katayama, Atsushi; Nakashima, Mikio; Takahashi, Kuniaki; Hoshino, Hitoshi*
no journal, ,
no abstracts in English
Kobayashi, Hitoshi*; Kurihara, Toshikazu*; Matsumoto, Hiroshi*; Yoshioka, Masakazu*; Matsumoto, Noriyuki*; Kumada, Hiroaki*; Matsumura, Akira*; Sakurai, Hideyuki*; Hiraga, Fujio*; Kiyanagi, Yoshiaki*; et al.
no journal, ,
no abstracts in English
Masunaga, Kosuke; Sato, Toshinori; Okihara, Mitsunobu*; Tsuji, Masakuni*; Nakashima, Hitoshi*; Saito, Akira*
no journal, ,
Study on characterization of liquid-type colloidal silica grout under sea water has been performed for the countermeasures against water inflow in the underground construction. This report shows the outline of this study.
Tsuji, Masakuni*; Okihara, Mitsunobu*; Nakashima, Hitoshi*; Saito, Akira*; Sato, Toshinori; Aoyagi, Kazuhei
no journal, ,
Study on characterization of liquid-type colloidal silica grout under sea water has been performed. Status of technology for grouting in the field of geological disposal in foreign countries has been understood by literature survey and site inspection.
Nakashima, Hitoshi*; Okihara, Mitsunobu*; Tsuji, Masakuni*; Saito, Akira*; Sato, Toshinori; Masunaga, Kosuke
no journal, ,
Study on characterization of liquid-type colloidal silica grout under sea water has been performed. This report shows the results of laboratory tests.
Nakashima, Hitoshi*; Saito, Akira*; Tsuji, Masakuni*; Sato, Toshinori; Aoyagi, Kazuhei; Masunaga, Kosuke*
no journal, ,
Study on characterization of liquid-type colloidal silica grout under sea water has been performed. This report shows the results of laboratory tests.
Tsuji, Masakuni*; Okihara, Mitsunobu*; Nakashima, Hitoshi*; Sato, Toshinori; Masunaga, Kosuke*
no journal, ,
Study on characterisation of colloidal silica grout under sea water including developing theoretical model and numerical simulation applicable to sea water has been performed.
Kimura, Shun; Takeda, Masaki; Okihara, Mitsunobu*; Nakashima, Hitoshi*; Chijimatsu, Masakazu*; Ito, Ayumu*
no journal, ,
no abstracts in English