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Tang, J.*; Yamamoto, Susumu*; Koitaya, Takanori*; Yoshigoe, Akitaka; Tokunaga, Takuma*; Mukai, Kozo*; Matsuda, Iwao*; Yoshinobu, Jun*
Applied Surface Science, 480, p.419 - 426, 2019/06
Times Cited Count：10 Percentile：49.82(Chemistry, Physical)Mass transports during hydrogen adsorption and absorption processes of PdCu alloys that has advantages of higher hydrogen diffusivity and economically lower-cost than the other Pd-alloys were studied. The research was made with a comparison of the well-known ordered phase of the bcc structure (the B2 phase) and a mixed phase of the fcc and B2 structures. 
ultrahigh vacuum X-ray photoelectron spectroscopy and ambient pressure X-ray photoelectron spectroscopy using synchrotron radiation were carried out to trace the chemical states of the Pd and Cu atoms as a function of temperatures. It is elucidated that the initial adsorption and absorption processes were similar in the two phases, but a hydrogen diffusion rate to the bulk was higher in the ordered phase than in the mixed one. We found the dynamics of the Pd and Cu atoms during the hydrogen adsorption/absorption processes largely depend on temperature. In the hydrogen atmosphere, the Pd atoms segregate at the surface below 373 K and Cu atoms segregate at the surface above 373 K. The present results agree well with the previous theoretical calculations and, thus, provide appropriate inputs toward developments of the hydrogen permeation materials.
Morishita, Yuki; Yamamoto, Seiichi*; Momose, Takumaro; Kaneko, Junichi*; Nemoto, Norio
Radiation Protection Dosimetry, 178(4), p.414 - 421, 2018/03
Times Cited Count：0 Percentile：0.01(Environmental Sciences)Plutonium dioxide (PuO
) is used to fabricate a mixed oxide fuel for fast breeder reactors. When a glove box containing PuO fails, such as by rupture of a glove or a vinyl bag, airborne contamination of plutonium (Pu) can occur. If the worker inhale PuO particles, they deposit in the lung and cause lung cancer. The nasal smear and nose blow methods are useful for checking workers for PuO intake in the field. However, neither method can evaluate the quantitative activity of Pu. No alpha-particle detector that can be used for direct measurements in the nasal cavity has been developed. Therefore, we developed a nasal monitor capable of directly measuring the activity of Pu in the nasal cavity to precisely evaluate the internal exposure dose of a worker. Prismatic-shaped 2
2 acrylic light guides were used to compose a detector block, and a ZnS(Ag) scintillator was adhered to the surface of these light guides. Silicon photomultiplier (SiPM) arrays with 88 channels were used as a photodetector. Actual PuO particles were measured using the nasal monitor. The nasal monitor could be directly inserted in the nasal cavities. The activity distribution of Pu was obtained by the nasal monitor. The average efficiencies in 4
were 11.43% and 11.58% for the left and right nasal cavities, respectively. The effect of 
and 
rays on the detection of the alpha particles of Pu was negligible. The difference in the measured Pu activity between the ZnS(Ag) scintillation counter and the nasal monitor was within 4.0%. The developed nasal monitor can solve the uncertainty problem encountered with the nasal smear and the nose blow methods. We expect this monitor to be useful for accurately estimating the internal exposure dose of workers.
Ishii, Katsunori; Suzuki, Masahiro; Yamamoto, Takuma; Kihara, Yoshiyuki; Kato, Yoshiyuki; Kurita, Tsutomu; Yoshimoto, Katsunobu; Yasuda, Masatoshi*; Matsusaka, Shuji*
Journal of Chemical Engineering of Japan, 42(5), p.319 - 324, 2009/05
Times Cited Count：7 Percentile：29.75(Engineering, Chemical)The flowability of coarse particles has been experimentally investigated using the vibrating tube method, to evaluate the applicability of this method to MOX (mixed oxide of PuO and UO) particles which are nuclear fuel used for electric power production. Five sizes of non-radioactive model particles, smaller than 850 micrometers, made of ZrO were prepared, and the experiments were carried out using vibrating tubes with an outlet diameter from 2 to 4 mm. The outlet diameter significantly affected the flowability measurements. When using the tube with a 4-mm-outlet diameter, the flowability of all the model particles was successfully measured. The inclination angle of the tube, also, affected the flowability measurements. From the advantages of high sensitivity, short measurement time, simple structure, and easy operation, the vibrating tube method is expected to be applied to the remote flowability measurement of the MOX particles.
Suzuki, Masahiro; Ishii, Katsunori; Yamamoto, Takuma; Kihara, Yoshiyuki; Kato, Yoshiyuki; Kurita, Tsutomu; Yoshimoto, Katsunobu; Fujii, Kanichi
Proceedings of Global Congress on Microwave Energy Applications (GCMEA 2008/MAJIC 1st), p.501 - 504, 2008/08
The natural resources, oil and uranium, would dry up around the midway of this century. FBR cycle most probably rescues this difficult situation. Mass production of MOX fuel for FBR, therefore, is the supreme subject to Japanese energy strategy. For this subject, we are attacking with Microwave heating technology. Up to present, we have succeeded to produce excellent PuO/UO bulk, 2 kgMOX/batch, advancing toward the mass production target, 5 kgU/h for one batch.
Ishii, Katsunori; Suzuki, Masahiro; Yamamoto, Takuma; Kihara, Yoshiyuki; Yasuda, Masatoshi*; Matsusaka, Shuji*
Funtai Kogakkai-Shi, 45(5), p.290 - 296, 2008/05
Particle flowability test using a vibrating tube with a tapered end was carried out to evaluate the applicability of this method to the analysis of MOX particles for nuclear fuel pellet fabrication. In this experiment, zirconia particles were used as model particles, which are less than several hundred micrometers in diameter. The sample particles were prepared by mixing the particles with different sizes, whose shape and surface state were changed by a mechanical treatment. The experimental results showed that the removal of smaller particles is more effective than the mechanical surface treatment to improve the flowability. Furthermore, it was found that the vibrating tube method can identify the difference of the particle flowability more easily and clearly than the method based on Carr's flowability index.
Yamamoto, Hideaki; Yoshizawa, Michio; Murakami, Hiroyuki; Momose, Takumaro*; Tsujimura, Norio*; Kanai, Katsuta*; Cruz-Suarez, R.*
Radiation Protection Dosimetry, 125(1-4), p.88 - 92, 2007/07
Times Cited Count：0 Percentile：0.01(Environmental Sciences)The purpose of this paper is to discuss the results of the third intercomparison exercise of external radiation dosimetry organized under the Regional Cooperative Agreement (RCA) in the East Asia region of the International Atomic Energy Agency (IAEA). Twenty five laboratories from 16 member states participated in the exercise. Japan Atomic Energy Research Institute (JAERI) and Japan Nuclear Cycle Development Institute (JNC) arranged the standard irradiation of the participants' dosimeters. The results of the measurements of the irradiated dosimeters for the determination of external doses were satisfactory for all participants, demonstrating good performance in their external dosimetry.
Tsujimura, Norio; Momose, Takumaro; Yoshizawa, Michio; Yamamoto, Hideaki; Cruz-Suarez, R.*; Murakami, Hiroyuki
no journal, ,
As one of the IAEA/RCA projects, three phases of personal dosimetry intercomparison programs had been conducted during the years of 1990 to 2004. The purpose of the program was to assess the ability of the personal dosimetry services in the RCA Member States and also to provide technical help in improving a performance of their dosimetry systems and in implementing the operational quantities recommended by ICRU. The purpose of this paper is to trace the history of and to present a summarized review of the results of the intercomparison programs. The trend of the phase-by-phase results showed that the quality of individual monitoring in most of the Member States has become dramatically improved to an acceptable level. There was a successful achievement and advancement over the 15 years effort.
Ishii, Katsunori; Suzuki, Masahiro; Yamamoto, Takuma; Kihara, Yoshiyuki; Matsusaka, Shuji*; Yasuda, Masatoshi*; Suna, Takayuki*; Kurita, Tsutomu; Kato, Yoshiyuki
no journal, ,
JAEA is developing simplified pelletizing MOX fuel fabrication process for fast breeder reactor. The final product of de-nitration, conversion and granulation process, are MOX fuel particles, of which diameter is hundres micrometer. These particles should have high flowability for easy handling in next process. The powder flowability is now evaluated by Carr's flowability index. In this oral presentation, the feasibility of powder flowability evaluation using vibrationg capillary method is investigated, employing ZrO particles of shich parameters are diameter and particle shape (shapes are varied by gronding particle edge). Screening small particles under about 100 micrometer contribute best the improvement of powder flowability, screening small particle under 50 micrometer in the second, and rounding particle shape in the third.
Ishii, Katsunori; Suzuki, Masahiro; Yamamoto, Takuma; Kihara, Yoshiyuki; Kurita, Tsutomu; Kato, Yoshiyuki; Yasuda, Masatoshi*; Matsusaka, Shuji*; Yoshimoto, Katsunobu
no journal, ,
Particle flowability test using a vibrating tube with a tapered end was carried out to evaluate the applicability of this method to the analysis of MOX particles for nuclear fuel pellet fabrication. In this experiment, zirconia particles were used as model particles, which are less than 850 micrometers in diameter. The sample particles were prepared by mixing the particles with different sizes. The experimental results showed that stable fowability evaluation is possible for particles larger than 45 micrometers and less than 850 micrometres, adjusting outlet diameter of tube and inclination angle of tube.
Kato, Yoshiyuki; Kurita, Tsutomu; Matsumoto, Masaki; Suzuki, Masahiro; Ishii, Katsunori; Yamamoto, Takuma; Kihara, Yoshiyuki; Yoshimoto, Katsunobu; Fujii, Kanichi
no journal, ,
An earlier accomplishment of FBR(fast breeder reactor) fuel cycle is the supreme subject from the point of view on the protection of environment by suppressing the green house effect as well as saving the oil. Microwave heating (MH) is employed as the MOX (mixed oxides U-Pu) production process in the main stream of FBR cycle. Thus, we are the optimization of MH method. We will describe the practical work of MOX fuel production which recycles the consumed nuclear fuel containing both U and Pu. The MH is employed to solidify the mixed solution by evaporating nitric acid and water. We call this processing de-nitration. The physical, mechanical, and chemical characteristics of the products are analyzed, being thereby discussed the contribution of the MH technology to the MOX fuel production. And, optimization of MH is discussed from the view point of design of MH oven, regulation of MH power, and combination with several auxiliary heating sources.
Ishii, Katsunori; Yamamoto, Takuma; Suzuki, Masahiro; Kihara, Yoshiyuki; Kato, Yoshiyuki; Kurita, Tsutomu; Yoshimoto, Katsunobu; Yoshimura, Tadahiro*
no journal, ,
To confirm the prospect of the simplified pellet production technology, JAEA is developing mass production technology for de-nitration conversion based on microwave heating. Base on the experimental result, the suitable processes for the mass production, are selected.
Ishii, Katsunori; Suzuki, Masahiro; Yamamoto, Takuma; Kihara, Yoshiyuki; Kurita, Tsutomu; Kato, Yoshiyuki; Yoshimoto, Katsunobu; Yasuda, Masatoshi*; Matsusaka, Shuji*
no journal, ,
The feasibility study on applyiing the vibrating tube method to the MOX powder for FBR fuel production has been carried out. it is favorable to reduce the sample amount for effective flowability measurement. In this study, the possibility to reduce the sample amount in the vibrating tube method was investigated, analizing the influence of the sample amount on flowability profiles.
Fukui, Kunihiro*; Arimitsu, Naoki*; Yamamoto, Tetsuya*; Yoshida, Hideto*; Yamamoto, Takuma*; Ishii, Katsunori; Suzuki, Masahiro
no journal, ,
no abstracts in English
Saiki, Yuta*; Fukui, Kunihiro*; Yamamoto, Tetsuya*; Yoshida, Hideto*; Yamamoto, Takuma*; Ishii, Katsunori; Suzuki, Masahiro
no journal, ,
no abstracts in English
Mizuno, Takashi; Nanjo, Isao; Yamamoto, Nobuyuki; Miyakawa, Kazuya; Murakami, Takuma
no journal, ,
This study aimed to understand the hydrochemical evolution process at Horonobe area, northern Hokkaido Japan, based on chemical tracers. In this study, existing data was used for the estimation. As the result, it is revealed that the resolution of gas hydrate and the diffusion of porewater from upper strata to lower strata is important factor of hydrochemical evolution.
Morishita, Yuki; Yamamoto, Seiichi*; Momose, Takumaro; Kaneko, Junichi*; Nemoto, Norio
no journal, ,
Plutonium dioxide (PuO) is used to fabricate mixed oxide fuel for fast breeder reactors. When airborne contamination of Pu occurs, the presence of Pu in the nasal cavity of a worker should be instantly evaluated. The nasal smear method is usual method to immediately evaluate the intake of PuO at a work site. However, this method cannot evaluate the activity of Pu quantitatively because the removable factor of PuO can be changed by the nasal swab and the pressure of a finger. An alpha-particle detector that can directly measure the nasal cavity has not yet been developed. Therefore, we developed a nasal monitor that can directly measure the activity of Pu in the nasal cavity in order to exactly evaluate the internal exposure dose of a worker. For our device, a ZnS(Ag) scintillator was attached to the surface of a 3 mm 3 mm 20 mm prismatic-shaped light guide. A Silicon Photomultiplier (SiPM) array was used to detect the scintillation light from the ZnS (Ag) scintillator. 
Am source was collimated to 2 mm 5 mm and was used to evaluate the efficiency of the nasal monitor. Alpha particles were irradiated from three different faces to the scintillator for the left and right nasal cavities. In addition, the effects of gamma and beta rays on the nasal monitor were evaluated. The positions of both the left and right nasal cavities could be identified based on the two-dimensional distribution of the alpha particles. The average efficiency was comparable to the ZnS(Ag) scintillation survey meter. The effect of the gamma and beta rays was negligible for Pu monitoring. Considering these efficiencies and the self-absorption factor of alpha particles, the exact activity of Pu in the nasal cavity can be instantly evaluated.
