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Journal Articles

Laser-driven neutron generation realizing single-shot resonance spectroscopy

Yogo, Akifumi*; Lan, Z.*; Arikawa, Yasunobu*; Abe, Yuki*; Mirfayzi, S. R.*; Wei, T.*; Mori, Takato*; Golovin, D.*; Hayakawa, Takehito*; Iwata, Natsumi*; et al.

Physical Review X, 13(1), p.011011_1 - 011011_12, 2023/01

 Times Cited Count:1 Percentile:90.46(Physics, Multidisciplinary)

Journal Articles

Design and actual performance of J-PARC 3 GeV rapid cycling synchrotron for high-intensity operation

Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.

Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09

 Times Cited Count:3 Percentile:80.29(Nuclear Science & Technology)

In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.

Journal Articles

Japanese population dose from natural radiation

Omori, Yasutaka*; Hosoda, Masahiro*; Takahashi, Fumiaki; Sanada, Tetsuya*; Hirao, Shigekazu*; Ono, Koji*; Furukawa, Masahide*

Journal of Radiological Protection, 40(3), p.R99 - R140, 2020/09

 Times Cited Count:18 Percentile:78.08(Environmental Sciences)

UNSCEAR and the Nuclear Safety Research Association report the annual effective doses from cosmic rays, terrestrial radiation, inhalation and ingestion from natural sources. In this study, radiation doses from natural radiation sources in Japan were reviewed with the latest knowledge and data. Total annual effective dose from cosmic-ray exposure can be evaluated as 0.29 mSv. The annual effective dose from external exposure to terrestrial radiation for Japanese population can be evaluated as 0.33 mSv using the data of nationwide survey by the National Institute of Radiological Sciences. The Japan Chemical Analysis Center (JCAC) performed the nationwide radon survey using a unified method for radon measurements in indoor, outdoor and workplace. The annual effective dose for radon inhalation was estimated using a current dose conversion factor, and the values were estimated to be 0.50 mSv. The annual effective dose from thoron was reported as 0.09 mSv by UNSCEAR and then the annual effective dose from inhalation can be described as 0.59 mSv. According to the report of large scale survey of foodstuff by JCAC, the effective dose from main radionuclides due to dietary intake can be evaluated to be 0.99 mSv. Finally, Japanese population dose from natural radiation can be assessed as 2.2 mSv which is near to the world average value of 2.4 mSv.

Journal Articles

Towards enhancement of test facilities for supporting nuclear decommissioning by remote technology

Kawabata, Kuniaki; Mori, Fumiaki*; Shirasaki, Norihito; Tanifuji, Yuta; Hanari, Toshihide

Proceedings of 2017 IEEE/SICE International Symposium on System Integration (SII 2017), p.450 - 455, 2018/02

This paper describes the test facilities and experimental environments for supporting the decommissioning of the nuclear facilities especially Fukushima Daiichi Nuclear Power Station by remote operation. Naraha Remote Technology Development Center of Japan Atomic Energy Agency is an institution for such purpose. Mock-up staircase, robot testing pool and motion capture arena are already installed and full service and support began from April, 2016. We are also designing and developing some experimental environment for remotely operated robots for nuclear decommissioning. In this paper, we describe current status and development of test facilities of Naraha Remote Technology Development Center, Japan Atomic Energy Agency.

Journal Articles

Design of test methods for remotely operated robots utilized for decommissioning tasks

Kawabata, Kuniaki; Tanifuji, Yuta; Mori, Fumiaki; Shirasaki, Norihito

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 4 Pages, 2017/04

This paper describes to develop test methods for evaluation of remotely operated robots and operator proficiency for nuclear emergency response and decommissioning tasks. We summarized representative robot's behaviors in the actual operations by the time analysis approach. We also examined environmental factors from the view point of the operation efficiency. Based on these examinations, we currently design some modules of the field for testing remotely operated machines. The approach and progress of the test method development are reported.

Journal Articles

Measurement of the displacement cross-section of copper irradiated with 125 MeV protons at 12 K

Iwamoto, Yosuke; Yoshiie, Toshimasa*; Yoshida, Makoto*; Nakamoto, Tatsushi*; Sakamoto, Masaaki*; Kuriyama, Yasutoshi*; Uesugi, Tomonori*; Ishi, Yoshihiro*; Xu, Q.*; Yashima, Hiroshi*; et al.

Journal of Nuclear Materials, 458, p.369 - 375, 2015/03

 Times Cited Count:12 Percentile:73.52(Materials Science, Multidisciplinary)

To validate Monte Carlo codes for the prediction of radiation damage in metals irradiated by $$>$$100 MeV protons, defect-induced electrical resistivity changes of copper related to the displacement cross-section were measured with 125 MeV proton irradiation at 12 K. The cryogenic irradiation system was developed with a Gifford-McMahon cryocooler to cool the sample via an oxygen-free high-conductivity copper plate by conduction cooling. The sample was a copper wire with a 250$$mu$$m diameter and 99.999% purity sandwiched between two aluminum nitride ceramic sheets. The resistivity increase did not change during annealing after irradiation below 15 K. The experimental displacement cross-section for 125 MeV irradiation shows similar results to the experimental data for 1.1 and 1.94 GeV. Comparison with the calculated results indicated that the defect production efficiency in Monte Carlo codes gives a good quantitative description of the displacement cross-section in the energy region $$>$$ 100 MeV.

JAEA Reports

DOSE-Analyzer; A Computer program with graphical user interface to analyze absorbed dose inside a body of mouse and human upon external neutron exposure

Satoh, Daiki; Takahashi, Fumiaki; Shigemori, Yuji*; Sakamoto, Kensaku

JAEA-Data/Code 2010-004, 28 Pages, 2010/06

JAEA-Data-Code-2010-004.pdf:1.58MB

DOSE-Analyzer is a computer program to retrieve the dose information from a database and generate a graph through a user-friendly graphical interface. The database is constructed for absorbed dose, fluence, and energy distribution inside a body of mouse and human exposed upon external neutrons, which is calculated by our developed Monte-Carlo simulation method using voxel-type phantom and particle transport code PHITS. The input configuration such as irradiation geometry, subject, and energy is set by GUI. The results are tabulated at particle types, i.e. electron, proton, deuteron, triton, and alpha particle, and target organs on a data sheet of Microsoft Office Excel. Simple analysis to compare the output values for two subjects is also performed on DOSE-Analyzer. This report is a user manual of DOSE-Analyzer.

JAEA Reports

Development of Radiation Dose Assessment System for Radiation Accident (RADARAC)

Takahashi, Fumiaki; Shigemori, Yuji*; Seki, Akiyuki

JAEA-Data/Code 2009-008, 127 Pages, 2009/07

JAEA-Data-Code-2009-008.pdf:10.5MB

A radiation transport calculation can derive dose distribution in a heavily exposed person for the medical treatment at the case of an accident. Since the accident cannot be prospected, many complicated procedures are needed to make the input file soon after the accident and to inform radiation dose based upon the output files with much information concerning the calculation. Thus, ($underline{Ra}$)diation ($underline{D}$)ose ($underline{A}$)ssessment system for ($underline{R}$)adiation ($underline{Ac}$)cident (RADARAC) was developed to derive effectively radiation dose by the MCNPX or the MCNP code. RADARAC consists of RADARAC_INPUT and RADARAC_DOSE. A user can interactively set up necessary resources to make input files with three programs in RADARAC_INPUT. The results of radiation doses are indicated with tables, graphs and figures depicting dose distribution by RADARAC_DOSE. It is confirmed that RADARAC can make input files with a few thousand lines and indicate more than 20,000 data dose within a few minutes.

Journal Articles

Dose assessment system for a heavily exposed person in radiation facility

Takahashi, Fumiaki; Shigemori, Yuji*; Seki, Akiyuki

Hozengaku, 8(1), p.56 - 61, 2009/04

Failure of safety management system can bring about a heavily exposed person in maintenance of a radiation facility, though such a case is very rare. A method using radiation transport code has advantages in an assessment of dose distribution inside a human body. Complicated procedures, however, are needed to prepare an input-file and to derive radiation dose based upon descriptions of an output-file in a numerical analysis using a radiation transport code. Thus, a system was developed to set up necessary information for an input file and to give radiation dose from an output file by a dialogue method using graphical user interfaces. Dose assessment can be effectively carried out for a radiological accident with this system.

Journal Articles

Accurate dose assessment system for an exposed person utilising radiation transport calculation codes in emergency response to a radiological accident

Takahashi, Fumiaki; Shigemori, Yuji*; Seki, Akiyuki

Radiation Protection Dosimetry, 133(1), p.35 - 43, 2009/01

 Times Cited Count:1 Percentile:10.23(Environmental Sciences)

A system has been developed to assess radiation dose distribution inside a body of exposed persons in a radiological accident by utilizing radiation transport calculation codes - MCNP and MCNPX. The system mainly consists of two parts, pre-processor and post-processor of the radiation transport calculation. Programs for the pre-processor are used to set up a "problem-dependent" input file, which defines the accident condition and dosimetric quantities to be estimated. The developed program for the post-processor part can effectively indicate dose information based upon the output file of the code. All of the programs in the dosimetry system can be executed with a generally used personal computer and accurately give the dose profile to an exposed person in a radiological accident without complicated procedures. An experiment using a physical phantom was carried out to verify the availability of the dosimetry system with the developed programs in a $$gamma$$-ray irradiation field. The dosimetry system with the developed programs can appropriately assess dose distribution inside or on the human body, if the user exactly define the source and human models and their geometric relationship.

Journal Articles

Design of beam optics in the proton beam transport line from synchrotron to spallation neutron target

Meigo, Shinichiro; Noda, Fumiaki*; Fujimori, Hiroshi*; Ikeda, Yujiro

Proceedings of ICANS-XVI, Volume 3, p.967 - 976, 2003/07

In J-PARC project, spallation target is irradiated by 3 GeV proton beam of 1 MW. Due to hands on maintenance for the proton beam lines, loss of proton beam is limited less than 1 W/m. Since it is difficult to predict the phase space distribution of the proton beam, we decided that the beam line have to be larger acceptance for 324 $$pi$$ mrad, which is determined by the collimator located in the synchrotron. Distortion of proton beam is caused by the by the instability of angle at the extraction of 3-GeV synchrotron, miss alignment of the magnet, and un-uniformity of the magnet field. In this study, the distortion is calculated. In order to fit the conditions, the stability of extraction angles should be kept smaller than 0.2 mrad. As for the magnetic field, it is found that the uniformity should be kept better 5x10$$^{-4}$$ and 2x10$$^{-3}$$ for bending and quadruple magnets, respectively. It is also found the error of alignments should be limited smaller than 1.0 mm and 1.0 mrad.

Oral presentation

Development of precise dose analysis system in a radiation accident, 2

Takahashi, Fumiaki; Shigemori, Yuji*; Seki, Akiyuki

no journal, , 

no abstracts in English

Oral presentation

The GROund Water Data Analyzing System (GROWDAS) of wide applicability utilizing quadrapole mass spectrometer for monitoring the dissolved gas

Shimada, Koji; Tanaka, Hidemi*; Hirokawa, Tomotaka*; Saito, Tomohiko*; Tsunomori, Fumiaki*

no journal, , 

no abstracts in English

Oral presentation

Evaluation of the MONJU fuel temperature during transients with a fluctuation plutonium isotopic composition, 2; Effect about effective delayed neutron fraction

Yamada, Fumiaki; Mori, Takero; Miyakawa, Akira; Konomura, Mamoru

no journal, , 

no abstracts in English

Oral presentation

Evaluation of the MONJU fuel temperature during transients with a fluctuation of the plutonium isotopic composition, 1; Effect about Reactivity coefficient

Mori, Takero; Yamada, Fumiaki; Miyakawa, Akira; Konomura, Mamoru

no journal, , 

no abstracts in English

Oral presentation

Structural code for manufacturing of structures for ITER TF coils

Nakajima, Hideo; Niimi, Kenichiro; Omori, Junji; Takano, Katsutoshi; Kawano, Katsumi; Tsutsumi, Fumiaki; Hamada, Kazuya; Okuno, Kiyoshi

no journal, , 

no abstracts in English

Oral presentation

Development of Monju plant dynamics analysis code, 1; Development plan

Yamada, Fumiaki; Kimura, Koichi; Jo, Takahisa; Mori, Takero; Morizono, Koji; Tamayama, Kiyoshi; Miyakawa, Akira

no journal, , 

In this report that development plan of Monju plant dynamics analysis code.

Oral presentation

Safety approach to severe accident for new nuclear safety regulation, 3; Present status of the safety evaluation for the CDA prevention on the fast reactor

Yamada, Fumiaki; Kurisaka, Kenichi; Takano, Kazuya; Mori, Tetsuya

no journal, , 

Present status of the safety evaluation for the CDA prevention on the Fast Reactor based on new nuclear safety regulation.

Oral presentation

Investigations of personal dose characteristics involved Fukushima Daiichi reactor accident, 4; Field test, 2; Response of the personal dosemeter on the phantoms and result of a measurement of the ambient dose and the energy spectrum of $$gamma$$ rays

Yamazaki, Takumi; Takada, Chie; Nakamura, Keisuke; Sagawa, Naoki; Hoshi, Katsuya; Nakagawa, Takahiro; Takimoto, Misaki; Tanimura, Yoshihiko*; Takahashi, Fumiaki; Momose, Takumaro; et al.

no journal, , 

no abstracts in English

Oral presentation

Development of the device for electrical resistivity measurements for proton irradiation under cryogenic condition

Iwamoto, Yosuke; Yoshiie, Toshimasa*; Yoshida, Makoto*; Nakamoto, Tatsushi*; Sakamoto, Masaaki*; Kuriyama, Yasutoshi*; Uesugi, Tomonori*; Ishi, Yoshihiro*; Xu, Q.*; Yashima, Hiroshi*; et al.

no journal, , 

To validate the radiation damage calculation in the PHITS code for proton irradiation over 100 MeV, we have developed the device for electrical resistance measurement under cryogenic condition. A copper wire with 99.999% purity in a diameter of 250-$$mu$$m was set with a serpentine-shaped line on the AlN sheet which has high thermal conductivity and electric insulation. The sample was annealed for 1 h at 1,000$$^{circ}$$C before irradiation. After annealing, the sample was cooled with an oxygen-free high-conductivity copper plate by conduction cooling. The electrical resistivity changes in the sample were measured using the four-probe technique. As a result, the residual resistivity ratio of the sample was about 1,800 between room temperature and 11 K. After 125 MeV proton irradiation with 1.45$$times$$10$$^{14}$$(proton/cm$$^{2}$$) at 11 K, the total resistance increase was 1.53$$mu$$ $$Omega$$, while the resistivity of copper before irradiation was 29.41$$mu$$ $$Omega$$.

33 (Records 1-20 displayed on this page)