Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Kawanishi, Tomohiro; Kurata, Masaki; Kaji, Yoshiyuki; Fukahori, Tokio; Nozawa, Takashi*; Sato, Daiki*; Murakami, Nozomu*; et al.
Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.206 - 216, 2019/09
After the nuclear accident at Fukushima Daiichi Power Plant, research and development (R&D) program for establishing technical basis of accident-tolerant fuel (ATF) started from 2015 in Japan. Since then, both experimental and analytical studies necessary for designing a new light water reactor (LWR) core with ATF candidate materials are being conducted within the Japanese ATF R&D Consortium for implementing ATF to the existing LWRs, accompanying with various technological developments required. Until now, we have accumulated experimental data of the candidate materials by out-of-pile tests, developed fuel evaluation codes to apply to the ATF candidate materials, and evaluated fuel behavior simulating operational and accidental conditions by the developed codes. In this paper, the R&D progresses of the ATF candidate materials considered in Japan are reviewed based on the information available such as proceedings of international conference and academic papers, providing an overview of ATF program in Japan.
Takai, Toshihide; Sato, Isamu*; Yamashita, Shinichiro; Furukawa, Tomohiro
JAEA-Technology 2015-043, 56 Pages, 2016/02
JAEA-Technology-2015-043.pdf:23.14MB
Fundamental research on FP-chemistry for fission product release behaviors under severe accident was carried out for reinforcement of source term evaluation, and implementation of the 1F decommissioning R&D project. There were subjects to clarified (1) FP chemistry behavior between vapor species release and aerosol formation and (2) physical parameters which would be affect subsequent aerosol's chemical behavior, for improvement of FP transport model. Applicability of measuring/analyzing techniques presently used was studied for evaluating foregoing properties. And the validity was verified by trial measurements. In conclusion, Raman spectrometry and high temperature X-ray diffraction were hopeful to determine FP-chemical form against vapor/aerosol species and aerosol species, respectively. Combination use of cascade impactor and scanning type electron microscope with energy-dispersive X-ray spectrometry was hopeful to determine physical parameters of aerosol.
C and 
O nuclei by low-energy proton beamsAkagi, Takashi*; Yagi, Masashi*; Yamashita, Tomohiro*; Murakami, Masao*; Yamakawa, Yoshiyuki*; Kitamura, Keiji*; Ogura, Koichi; Kondo, Kiminori; Kawanishi, Shunichi*
Radiation Measurements, 59, p.262 - 269, 2013/12
Times Cited Count：17 Percentile：77.87(Nuclear Science & Technology)In proton therapy, positron emitters are induced from C andO nuclei by protons on the beam path in the patient. Many studies for monitoring positron emitters with beam-induced PET technique have been performed by various groups to verify the proton beam range and the dose in the patient for quality assurance. The aim of this study was to develop a method for measuring the production cross sections of positron emitters using standard equipment for proton therapy. The time-activity curve was then obtained with a high-sensitivity PET scanner to extract the number of positron emitters produced in the target. The production cross sections for four reaction channels: O(p,pn)
O, O(p,3p3n)
C, O(p,2p2n)
N, and C(p,pn)C were then measured. The cross sections for the O(p,pn)O reaction channel were consistent with data of previous experiments within the uncertainties, while those of C(p,pn)C were generally lower than data of previous experiments.
Kinjo, Tomohiro*; Nishikawa, Masabumi*; Yanashita, Naoya*; Koyama, Takanori*; Tanifuji, Takaaki*; Enoeda, Mikio
Fusion Engineering and Design, 82(15-24), p.2147 - 2151, 2007/10
Times Cited Count：22 Percentile：80.57(Nuclear Science & Technology)no abstracts in English
Konomura, Mamoru; Ogawa, Takashi; Okano, Yasushi; Yamaguchi, Hiroyuki; Murakami, Tsutomu; Takaki, Naoyuki; Nishiguchi, Youhei; Sugino, Kazuteru; Naganuma, Masayuki; Hishida, Masahiko; et al.
JNC TN9400 2004-035, 2071 Pages, 2004/06
JNC-TN9400-2004-035.pdf:76.42MB
The attractive concepts for Sodium-, lead-bismuth-, helium- and water-cooled FBRs have been created through using typical plant features and employing advanced technologies. Efforts on evaluating technological prospects of feasibility have been paid for these concepts. Also, it was comfirmed if these concepts satisfy design requierments of capability and performance presumed in the feasibilty study on commertialization of Fast Breeder Reactor Systems. As results, it was concluded that the selection of sodium-cooled reactor was most rational for practical use of FBR technologies in 2015.
Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Kawanishi, Tomohiro; Kurata, Masaki; Kaji, Yoshiyuki; Fukahori, Tokio; Nozawa, Takashi*; Sato, Daiki*; Murakami, Nozomu*; et al.
no journal, ,
Research and development (R&D) program for establishing technical basis of ATFs for light water reactor (LWR) started in 2015. Since then the R&D is being conducted in cooperation with power plant providers, fuel venders, research institutes and universities for making the most use of the experiences in R&D, practical design, and evaluations of fuels and cores of commercial LWRs. Among currently explored ATF candidate materials in the program, silicon carbide composite reinforced by SiC fiber (SiC/SiC) and FeCrAl steel strengthened by dispersion of fine oxide particles (FeCrAl-ODS) offer several attractive features including the remarkable high temperature capabilities and the slow kinetics of steam oxidation reactions. This presentation will give an overview of the progress in ATF development and review the current status of data availability and integrity for the properties and behaviors of ATF candidate materials, followed by discussion on the primary differences from zirconium alloy in the behaviors in the severe accident scenarios. Finally, subjects to be solved for practical use of ATF will be summarized.
Kaji, Yoshiyuki; Yamashita, Shinichiro; Nemoto, Yoshiyuki; Ioka, Ikuo; Osaka, Masahiko; Kawanishi, Tomohiro
no journal, ,
The JAIF International Cooperation Center will hold a local seminar in the Czech Republic as part of its efforts to promote cooperation through local seminars and invitations from Japan to countries that are promoting the expansion of nuclear power plants. In this seminar, we will introduce the current status of accident-resistant fuel development in Japan.
Yamashita, Shinichiro; Mohamad, A. B.; Ioka, Ikuo; Nemoto, Yoshiyuki; Kawanishi, Tomohiro; Osaka, Masahiko; Kaji, Yoshiyuki
no journal, ,
After the nuclear accident at Fukushima Daiichi power plant, global interest has expanded in exploring fuels with enhanced performance during severe accident, and enhancing the accident tolerance of light water reactors (LWRs) became a topic of serious discussion all over the world. In Japan, research and development (R&D) program for establishing technical basis of ATF has been conducted by JAEA in cooperation with power plant providers, fuel venders and universities. In this presentation, the overview of ATF R&D program in Japan will be introduced with the explanation on JAEA's role in ATF R&D program including the recent result from fundamental ATF studies.
Yamashita, Shinichiro; Nemoto, Yoshiyuki; Ioka, Ikuo; Osaka, Masahiko; Kawanishi, Tomohiro; Kaji, Yoshiyuki
no journal, ,
After the nuclear accident at Fukushima Daiichi power plant, global interest has expanded in exploring fuels with enhanced performance during severe accident, and enhancing the accident tolerance of light water reactors (LWRs) became a topic of serious discussion all over the world. In Japan, research and development (R&D) program for establishing technical basis of ATF has been conducted by JAEA in cooperation with power plant providers, fuel venders and universities. In this presentation, the overview of ATF R&D program in Japan will be introduced with the explanation on development status of each ATF elemental technology as well as JAEA's role in ATF R&D program.
Yamashita, Shinichiro; Nemoto, Yoshiyuki; Ioka, Ikuo; Osaka, Masahiko; Kawanishi, Tomohiro; Kaji, Yoshiyuki
no journal, ,
After the nuclear accident at Fukushima Daiichi power plant, global interest has expanded in exploring fuels with enhanced performance during severe accident, and enhancing the accident tolerance of light water reactors (LWRs) became a topic of serious discussion all over the world. In this panel session, the state-of-art knowledge and the latest development status of ATF from the point of view of industry, government, nonprofit research agencies, and academic representatives currently leading global ATF development will be presented and discussed. The significant challenges in development and implementation of ATF, such as large scale ATF fabrication, acceptance by nuclear utilities, the role of government and inter-government agencies in ATF research oversight, and the engineering and scientific challenges to develop ATF will be presented.
Sakaki, Hironao; Nishiuchi, Mamiko; Maeda, Shota; Ishida, Akihiro*; Yamashita, Tomohiro*; Katahira, Kei*; Pikuz, T.; Faenov, A.*; Esirkepov, T. Z.; Pirozhkov, A. S.; et al.
no journal, ,
We will tell about the measurement methods of the electron temperature from the laser-driven acceleration.
Miwa, Shuhei; Nakajima, Kunihisa; Di Lemma, F. G.; Suzuki, Chikashi; Yamashita, Shinichiro; Okane, Tetsuo; Takai, Toshihide; Takada, Juntaro; Furukawa, Tomohiro; Osaka, Masahiko
no journal, ,
JAEA conducts a fundamental research on fission product (FP) chemistry to construct the database of FP chemistry at each stage of nuclear power plants and improve FP chemistry models which will be reflected to the improvement of FP release and transport models. Main target of FP elements are Cs and I, and the evaluation of FP and B release kinetics, development of direct measurement technique of FP chemical form, the evaluation of Cs chemisorption behavior to SS, upgrading the thermodynamic database are carried out with focuses on Mo and BWR control material, boron carbide (B
C).
Yamashita, Shinichiro; Nemoto, Yoshiyuki; Ioka, Ikuo; Kawanishi, Tomohiro; Kurata, Masaki; Kaji, Yoshiyuki; Fukahori, Tokio
no journal, ,
After the 2011 Great East Japan Earthquake and Tsunami, and the events that followed at the Fukushima Daiichi Nuclear Power Station (1F), global interest has expanded in exploring fuels with enhanced performance during such rare events, with accident-tolerant fuel (ATF) development programs starting in many countries. In Japan, several ATF programs have been launched for feasibility study, development of manufacturing technology, and establishment of technical basis since the 1F accident. ATF candidate materials considered in Japan are silicon carbide (SiC) composite and FeCrAl steel strengthened by dispersion of fine oxide particles (FeCrAl-ODS). SiC composite is very attractive material because of its lower hydrogen generation rate and lower reaction heat in comparison with conventional Zirconium (Zr) alloys. Therefore, practical uses for a fuel cladding of pressurized water reactor (PWR) and for the fuel cladding, channel box of boiling water reactor (BWR) are expected. On the other hand, FeCrAl-ODS steel is a promising material and is considered to apply to the fuel cladding of BWR.
Takai, Toshihide; Sato, Isamu; Yamashita, Shinichiro; Furukawa, Tomohiro; Osaka, Masahiko
no journal, ,
Property evaluation methods of aerosol, which was released from the simulated FP release test apparatus, were considered, as part of the direct measurement technique of FP's chemical form. It is important to prevent thermal flow from having an effect by installing instruments, for evaluating aerosol property (chemical form, particle diameter distribution, and shape) under simulated severe accident conditions correctly. A low flow cascade impactor with a gas flow control system was installed to the test apparatus, and applicability for aerosol property evaluation was confirmed by heating test using simulated CsI.
Takai, Toshihide; Sato, Isamu*; Yamashita, Shinichiro; Furukawa, Tomohiro
no journal, ,
Aerosols are produced when the vapor species released from overheated fuels are transported to reactor cooling system under severe accident. The chemical forms of the aerosol may be determined a region between the vapors release and the aerosols formation. No information is available about the chemical forms in the region. The using of hypothesis chemical forms in source term evaluation becomes one of the causes of uncertainty. For the improving evaluation accuracy, it is necessary to obtain the chemical forms data in the region. Applicability of a cascade impactor was investigated to determine the material properties of right after the aerosol formation, because it had possibility to collect aerosols in the classified stage in each particle size and determine the material properties for each stage.
Osaka, Masahiko; Miwa, Shuhei; Yamashita, Shinichiro; Takai, Toshihide; Nakajima, Kunihisa; Furukawa, Tomohiro; Nagase, Fumihisa
no journal, ,
Fission product (FP) chemistry under the LWR severe accident (SA) conditions should be deeply understood for more accurate evaluation of FP release and transport behavior, which can lead to reduction of uncertainty in the evaluation of source term. This paper describes the contents of research program that is focused on the FP chemistry. Results of the FP chemical form just after release from fuel by a chemical equilibrium calculation considering dependences of release kinetics for related elements showed that dominant vapor species have changed according to the atmospheres and Cs-B-O species became dominant in the presence of BC. As for the Cs-chemisorption behavior, it was found by a literature review that resultant compounds formed by the Cs-chemisorption onto the SS could be divided into two categories, Cs-Cr-O and Cs-Si-O compounds.
Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Kawanishi, Tomohiro; Osaka, Masahiko; Kaji, Yoshiyuki
no journal, ,
After the nuclear accident at Fukushima Daiichi power plant, global interest has expanded in exploring fuels with enhanced performance during severe accident, and enhancing the accident tolerance of light water reactors (LWRs) became a topic of serious discussion all over the world. In Japan, research and development (R&D) program for establishing technical basis of ATF has been conducted by JAEA in cooperation with power plant providers, fuel venders and universities. In this presentation, the overview of ATF R&D program in Japan will be introduced with the explanation on JAEA's role in ATF R&D program.
Yamashita, Shinichiro; Mohamad, A. B.; Ioka, Ikuo; Nemoto, Yoshiyuki; Kawanishi, Tomohiro; Kaji, Yoshiyuki; Osaka, Masahiko; Murakami, Nozomu*; Owaki, Masao*; Sasaki, Masana*; et al.
no journal, ,
Japan's Accident Tolerant Fuel (ATF) research and development (R&D) program has been conducted since 2015 in cooperation with power plant providers, fuel venders and universities for making the most use of the experiences in R&D, practical design, and evaluations of fuels and cores of commercial Light Water Reactors (LWRs). An overview of the present R&D progress is given, in relation to the role of Japan Atomic Energy Agency (JAEA) in the program. The ATF candidate materials currently under consideration are the following three claddings: the silicon carbide (SiC) composite which is potentially applicable for Pressurized Water Reactor (PWR) and Boiling Water Reactor (BWR), the FeCrAl steel strengthened by dispersion of fine oxide particles (FeCrAl-ODS) for BWR, and Cr-coated zircalloy claddings for PWR. In addition to the cladding materials, R&D on the SiC-made BWR channel box and accident tolerant control rods are also underway.
Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Kurata, Masaki; Kawanishi, Tomohiro; Kaji, Yoshiyuki; Fukahori, Tokio; Watanabe, Seiichi*; Murakami, Nozomu*; Sato, Hisaki*; et al.
no journal, ,
In Japan, research and development (R&D) program for establishing technical basis of ATF started in 2015 and is being conducted in cooperation with power plant providers, fuel venders and universities for making the most use of the experiences in R&D, practical design, and evaluations of fuels and cores of commercial LWRs. The present paper reviews the progress of the development and summarizes subjects to be solved for ATF cladding, based on the attribute guide which was originally drawn up in the Japanese ATF R&D program as it should be an indicator of proper ATF development guidance.
Akagi, Takashi*; Yamashita, Tomohiro*; Uemoto, Kenji*; Sakaki, Hironao; Demizu, Yusuke*; Fuwa, Nobukazu*
no journal, ,
To develop a real-time two dimensional dosimetry with a scintillation screen. A multidimensional dosimetry system is needed for quality assurance of dose distributions in proton therapy, especially proton therapy with a pencil beam scanning system. An organic scintillation material is often used for the dosimetry systems due to the handleability; however organic scintillators have a poor linearity with respect to the linear energy transfer (LET). Meanwhile, inorganic scintillators have comparably good linearity to the LET; however they are difficult to handle. In this study we employ one of inorganic scintillators, silver- activated zinc sulfide, ZnS(Ag), as a scintillator because of the linearity to the LET.
