Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 44

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Background correction method for portable thyroid dose monitor using gamma-ray spectrometer developed at JAEA in high dose rate environment

Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Nishino, Sho; Takahashi, Masa

Radiation Measurements, 137, p.106389_1 - 106389_5, 2020/09

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

A portable thyroid dose monitoring system has been developed at the Japan Atomic Energy Agency (JAEA) to assess the thyroid equivalent dose for workers and members of the public in a high dose rate environment. The background (B.G.) photon correction is required for an accurate measurement in a high dose rate environment at an early stage after a nuclear accident. We developed the B.G. photon correction method using cylindrical PMMA phantoms.

Journal Articles

Prototype test of a portable thyroid dose monitoring system using gamma-ray spectrometers

Nishino, Sho; Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Takahashi, Masa

Radiation Measurements, 134, p.106292_1 - 106292_5, 2020/06

 Times Cited Count:2 Percentile:62.87(Nuclear Science & Technology)

In the situation of a severe nuclear accident, radioiodine monitoring in thyroid should be performed for a large number of people immediately after accident. The portable thyroid dose monitoring system which can be used in a high dose rate condition is in development. In this presentation, the result of performance test using prototype model will be described.

Journal Articles

Experimental determination of anisotropic emission of neutrons from $$^{252}$$Cf neutron source with the spherical protection case

Kowatari, Munehiko; Nishino, Sho; Romallosa, K. M. D.*; Yoshitomi, Hiroshi; Tanimura, Yoshihiko; Oishi, Tetsuya

Radiation Protection Dosimetry, 189(4), p.436 - 443, 2020/05

 Times Cited Count:0 Percentile:0.01(Environmental Sciences)

The anisotropic emission of neutrons from a cylindrical X1 $$^{252}$$Cf source with the spherical external casing was experimentally determined. The influence of metal materials and shapes of the external casing to the anisotropy factor, $$F_{I}$$($$theta$$) was assessed by the Monte Carlo calculation, before performing the measurement. The results of the calculation result implied that light and spherical-shaped external casing decreases the anisotropic emission of neutrons from a cylindrical source and the nature of the material does not affect the anisotropic emission to a large extent. The experimental results obtained when a spherical-shaped aluminum protection case was employed also revealed that the anisotropy factor was close to 1.0 with a wide zenith angle range.

Journal Articles

A Study of a calibration technique for a newly developed thyroid monitor and its uncertainties due to body size for radioiodine measurements

Yoshitomi, Hiroshi; Nishino, Sho; Tanimura, Yoshihiko; Takahashi, Masa

Radiation Measurements, 133, p.106279_1 - 106279_6, 2020/04

 Times Cited Count:2 Percentile:62.87(Nuclear Science & Technology)

Uncertainty of the body size on the counting efficiency of a newly developed thyroid monitor was estimated by Monte Carlo simulations using several voxel phantoms. Overlying tissue thickness was a major impact factor on the counting efficiency. As a result, uncertainty related to the body size of the monitored subject was found to be 25%.

Journal Articles

Establishment of a low dose rate gamma ray calibration field for environmental radiation monitoring devices

Kowatari, Munehiko; Yoshitomi, Hiroshi; Nishino, Sho; Tanimura, Yoshihiko; Oishi, Tetsuya; Kessler, P.*; Neumaier, S.*; R$"o$ttger, A.*

Radiation Protection Dosimetry, 187(1), p.61 - 68, 2019/12

 Times Cited Count:1 Percentile:23.13(Environmental Sciences)

Journal Articles

Corrigendum; Establishment of a low dose rate gamma ray calibration field for environmental radiation monitoring devices

Kowatari, Munehiko; Yoshitomi, Hiroshi; Nishino, Sho; Tanimura, Yoshihiko; Oishi, Tetsuya; Kessler, P.*; Neumaier, S.*; R$"o$ttger, A.*

Radiation Protection Dosimetry, 186(4), P. 538, 2019/12

 Times Cited Count:0 Percentile:1.45(Environmental Sciences)

In the original version of this article an error occurred in Table 5. In section (b), the unit $$mu$$Sv h$$^{-1}$$ has been amended to nSv h$$^{-1}$$. The corrected table appears below. The author apologises for this error.

Journal Articles

Determination of emission rates and spectra of neutrons from $$^{241}$$Am-Li sources

Hoshi, Katsuya; Nishino, Sho; Yoshida, Tadayoshi; Tsujimura, Norio

JPS Conference Proceedings (Internet), 24, p.011020_1 - 011020_6, 2019/01

We studied the application of AmLi interrogation neutron sources, which originally deployed in non-destructive assay apparatus for nuclear safeguard, to calibration work. To determine the emission rate, the angular distribution of neutron fluence was measured by a potable long counter. The emission rate at the date of measurement (October 23rd, 2015) was determined to be 1.00$$times$$10$$^{6}$$ n/s ($$pm$$4.1% (${it k}$ = 2)).

Journal Articles

Characteristics of commercially available CdZnTe detector as gamma-ray spectrometer under severe nuclear accident

Tanimura, Yoshihiko; Nishino, Sho; Yoshitomi, Hiroshi; Kowatari, Munehiko; Oishi, Tetsuya

Progress in Nuclear Science and Technology (Internet), 6, p.134 - 138, 2019/01

At the severe nuclear accidents like the Fukushima Daiichi Nuclear Power Plant, various radionuclides will be dispersed into the environment and raise the dose rate. The $$in$$-$$situ$$ measurements of $$gamma$$ ray spectra and identifying radionuclides using the results are important for the radiological protection from both external and internal exposure. For this application a commercially available CdZnTe spectrometer (Kromek GR-1) was characterized at the calibration fields of FRS/JAEA. The angular dependence of the detection efficiency was studied and the efficiency was kept within 15 % degradation in $$pm$$135 degree incident angle, which covers 85 % of all. The usable dose range was evaluated and the spectrometer could correctly measure the $$gamma$$ ray spectra below 200 $$mu$$Gy/h.

Journal Articles

Comprehensive study on the response of neutron dosimeters in various simulated workplace neutron calibration fields

Nishino, Sho; Hoshi, Katsuya; Tsujimura, Norio; Kowatari, Munehiko; Yoshida, Tadayoshi

Proceedings of 14th International Congress of the International Radiation Protection Association (IRPA-14), Vol.3 (Internet), p.1258 - 1263, 2017/11

In order to investigate how neutron dosimeters respond in the continuous neutron fields in workplaces, we performed performance tests of four widely-used neutron survey meters in various simulated workplace neutron calibration fields established in two calibration facilities (FRS and ICF) in JAEA. As a result, we found that survey meters significantly over or underestimate neutron dose in the fields which have spectral components only in the energy range below 1 MeV, while those show good performance in the fields which have spectral components in the energy range above 1 MeV.

Journal Articles

Assessment of equivalent dose of the lens of the eyes and the extremities to workers under nonhomogeneous exposure situation in nuclear and accelerator facilities by means of measurements using a phantom coupled with Monte Carlo simulation

Yoshitomi, Hiroshi; Hagiwara, Masayuki*; Kowatari, Munehiko; Nishino, Sho; Sanami, Toshiya*; Iwase, Hiroshi*

Proceedings of 14th International Congress of the International Radiation Protection Association (IRPA-14), Vol.3 (Internet), p.1188 - 1195, 2017/11

The equivalent doses to the lens of the eye and extremities for radiation workers should be assessed properly to ensure that the dose limits are not exceeded. Recently, the following two issues has pressed demand on more appropriate evaluation of the equivalent doses of the lens of the eye and extremity. One is the new occupational dose limit for the lens of the eye the ICRP recommended. The other is growing demand on handling of highly activated materials in the maintenance works of an accelerator and contaminated materials during the decommissioning works of nuclear facility, which increases the potential exposure risk to the extremities to a wider variety of radio-nuclides. Since the points to be assessed for the exposures to the lens of the eye and the extremities are apart from the trunk, the homogeneity of the radiation fields would be significantly impact on the assessment of these equivalent doses. However, there has been no sufficient and available method to identify the nonhomogeneous situations systematically in terms of the eye lens or extremity monitoring. The goal of this study is to provide the framework to identify the nonhomogeneous exposure situations. In order to fulfil this purpose, newly proposed indices to represent the homogeneity were calculated by Monte Carlo simulation incorporated with mathematical phantom, verifying the benchmark measurements. Important parameters that significantly impact on these indices were also shown from the various trials of calculations of homogeneity indices.

JAEA Reports

Case studies of radiation dose assessment in emergency situation of nuclear facilities

Kawasaki, Masatsugu; Nakajima, Junya; Yoshida, Keisuke; Kato, Saori; Nishino, Sho; Nozaki, Teo; Nakagawa, Masahiro; Tsunoda, Junichi; Sugaya, Yuki; Hasegawa, Rie; et al.

JAEA-Data/Code 2017-004, 57 Pages, 2017/03

JAEA-Data-Code-2017-004.pdf:2.34MB

In emergency situation of nuclear facilities, we need to estimate the radiation dose due to radiation and radioactivity to grasp the influence range of the accident in the early stage. Therefore, we prepare the case studies of dose assessment for public exposure dose and personal exposure dose and contribute them to emergency procedures. This document covers about accidents of nuclear facilities in Nuclear Science Research Institute and past accident of nuclear power plant, and it can be used for inheritance of techniques of emergency dose assessment.

Journal Articles

Development of the graphite-moderated neutron calibration fields using $$^{241}$$Am-Be sources in JAEA-FRS

Nishino, Sho; Tanimura, Yoshihiko; Ebata, Yoshiaki*; Yoshizawa, Michio

Journal of Radiation Protection and Research, 41(3), p.211 - 215, 2016/09

We developed the graphite-moderated neutron calibration fields using $$^{241}$$Am-Be sources at the Facility of Radiation Standard in the Japan Atomic Energy Agency. The neutron spectra of the fields were evaluated by Monte-Carlo calculation and measurements using the Bonner Multi-sphere Spectrometer. Reference values of fluence rates and dose equivalent rates of H$$^{*}$$(10) and H$$_{rm p}$$(10) were determined from neutron spectra by measurements. Currently, our fields are available for calibration or performance test of neutron measuring instruments.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2014

Watanabe, Hitoshi; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.

JAEA-Review 2015-030, 115 Pages, 2015/12

JAEA-Review-2015-030.pdf:25.28MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2014. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

Journal Articles

Progress of divertor simulation research toward the realization of detached plasma using a large tandem mirror device

Nakashima, Yosuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Oki, Kensuke*; Sakamoto, Mizuki*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; Imai, Tsuyoshi*; et al.

Journal of Nuclear Materials, 463, p.537 - 540, 2015/08

 Times Cited Count:17 Percentile:88.2(Materials Science, Multidisciplinary)

Journal Articles

Development of methods for removing the deposit in the combustion chamber of the water tube boiler

Kawasaki, Ichio; Ishiyama, Toru; Nishino, Shohei; Aoki, Masaru*

Boira Kenkyu, (391), p.8 - 14, 2015/06

no abstracts in English

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2013

Watanabe, Hitoshi; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Goto, Ichiro*; Kibe, Satoshi*; et al.

JAEA-Review 2014-040, 115 Pages, 2015/01

JAEA-Review-2014-040.pdf:4.26MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2013. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

Journal Articles

Development of divertor simulation research in the GAMMA 10/PDX tandem mirror

Nakashima, Yosuke*; Sakamoto, Mizuki*; Yoshikawa, Masayuki*; Oki, Kensuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; et al.

Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 8 Pages, 2014/10

Journal Articles

Mono-energetic neutron fields using 4 MV pelletron accelerator at FRS/JAEA

Tanimura, Yoshihiko; Kowatari, Munehiko; Yoshitomi, Hiroshi; Nishino, Sho; Yoshizawa, Michio

IAEA-TECDOC-1743, Annex (CD-ROM), p.133 - 138, 2014/07

Mono-energetic neutron calibration fields have been developed in the energy range of 8 keV to 19 MeV using a 4 MV Pelletron accelerator at the FRS in the JAEA. Protons or deuterons are accelerated and transported to bombard various targets for neutron production. The targets are prepared by depositing Sc, LiF or TiT on the backing disks for $$^{45}$$Sc(p,n)$$^{45}$$Ti, $$^{7}$$Li(p,n)$$^{7}$$Be and, $$^{3}$$H(p,n)$$^{3}$$He and $$^{3}$$H(d,n)$$^{4}$$He reactions, respectively. For $$^{2}$$H(d,n)$$^{3}$$He reaction, a gas target is prepared by filling a target cell with D$$_{2}$$ gas. A pulsed beam with a minimum width of 2 ns can be derived with the pulsing system. Neutron fluence rates were measured with a Bonner sphere, a Li glass detector, a Si-SSD with a polyethylene radiator and a BC501A detector. Though the maximum fluence rates should not be high enough to obtain the nuclear data using an activation method, they can be available to obtain the nuclear data by using the prompt $$gamma$$ ray analysis.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2012

Sumiya, Shuichi; Watanabe, Hitoshi; Miyagawa, Naoto; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki; Otani, Kazunori*; Hiyama, Yoshinori*; et al.

JAEA-Review 2013-041, 115 Pages, 2014/01

JAEA-Review-2013-041.pdf:19.01MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, and the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), this report describes the effluent control results of liquid waste discharged from the JAEA's Nuclear Fuel Cycle Engineering Laboratories in the fiscal year 2012, from 1st April 2012 to 31st March 2013. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other facilities were much lower than the authorized limits of the above regulations.

Journal Articles

Development of moderated neutron calibration field using a graphite pile and $$^{241}$$Am-Be sources

Nishino, Sho

Hokeikyo Nyusu, (52), p.2 - 4, 2013/10

no abstracts in English

44 (Records 1-20 displayed on this page)