Tokuyasu, Kayoko; Furuta, Sadaaki*; Kokubu, Yoko; Umeda, Koji
Nihon Hoshasen Anzen Kanri Gakkai-Shi, 15(1), p.80 - 87, 2016/07
An optically stimulated luminescence reader (Riso TL/OSL DA-20) was installed in Toki Research Institute of Isotope Geology and Geochronology (Toki-shi, Gifu Prefecture), Japan Atomic Energy Agency (JAEA) for dating the geological sample. An accumulated dose of the sample is obtained using the reader. Sealed beta source of strontium-90 is required to be mounted on the reader because repeated artificial irradiation is necessary for the accumulated dose estimation. However, there are not many introduction examples for the reader domestically, and the information as to radiation control of the reader is limited. We therefore report here the process of source loading on the reader and radiation control associated with the use of the source.
Isotope News, (718), p.46 - 49, 2014/02
no abstracts in English
Takeyasu, Masanori; Sumiya, Shuichi; Furuta, Sadaaki
Hoken Butsuri, 48(3), p.141 - 149, 2013/11
On the basis of airborne concentrations of radionuclides in the Nuclear Fuel Cycle Engineering Laboratories, JAEA, the committed effective dose to adult and committed equivalent dose to thyroid of infant by inhalation were estimated by setting the realistic parameters for indoor-outdoor air concentration ratio, inhalation rate and dose coefficient, and the margin of safety in projected dose was examined. As the results, the estimated doses were about 1/7 for the projected committed effective dose to adult and about 1/10 for the projected committed equivalent dose to thyroid of infant, respectively. These facts indicated that the projected dose had the degrees of safety margin of the factor of 7 for committed effective dose to adult and the factor of 10 for committed equivalent dose to thyroid of infant, respectively. It was the most important parameter for estimating the committed dose that the indoor-outdoor air concentration ratio.
Kurihara, Osamu*; Kanai, Katsuta; Nakagawa, Takahiro; Takada, Chie; Tsujimura, Norio; Momose, Takumaro; Furuta, Sadaaki
Journal of Nuclear Science and Technology, 50(2), p.122 - 129, 2013/02
no abstracts in English
Tsujimura, Norio; Yoshida, Tadayoshi; Furuta, Sadaaki
Proceedings of 13th International Congress of the International Radiation Protection Association (IRPA-13) (Internet), 10 Pages, 2012/05
Fujita, Hiroki; Nagaoka, Mika; Kono, Takahiko; Takeyasu, Masanori; Kawasaki, Masatsugu; Okura, Takehisa; Tsujimura, Norio; Sumiya, Shuichi; Momose, Takumaro; Furuta, Sadaaki
Proceedings of 13th International Congress of the International Radiation Protection Association (IRPA-13) (Internet), 7 Pages, 2012/05
The nuclear accident at Fukushima Dai-ichi Nuclear Power Station of Tokyo Electric Power Co. (TEPCO) was caused by the Tohoku District-off the Pacific Ocean Earthquake. Various kinds of radionuclides were released from the power station right after the accident occurred and then reached our laboratories. Therefore, environmental monitoring was reinforced by observation of air absorbed dose rate, periodic collection of airborne dust, precipitation. The collected samples were used to determine radioactivity of ray emitters by High pure Germanium semiconductor detector. Moreover, rainwater and humidity were collected to do the usual routine monitoring. In some samples, Sr, I, Cs and Cs were detected with radioactivity released from the Fukushima station. In other samples such as seawater, seabed soil and etc., similar radionuclides were detected including the influence of the accident.
Takeyasu, Masanori; Nakano, Masanao; Fujita, Hiroki; Nakada, Akira; Watanabe, Hitoshi; Sumiya, Shuichi; Furuta, Sadaaki
Journal of Nuclear Science and Technology, 49(3), p.281 - 286, 2012/03
As a response to the Fukushima Daiichi Nuclear Power Plant accident, emergency environmental radiation monitoring was performed at the Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency (JAEA). This paper provisionally describes the results of the monitoring including ambient radiation dose rate and radioactivity concentrations in airborne and fallout. The ambient radiation dose rate began to increase since about 1:00 on March 15 2011, and varied with three peak dose rate of several thousand Gy/h at 8:00 on March 15, at 5:00 on March 16, and at 4:00 on March 21. The variation over time in radioactivity concentrations in airborne and fallout almost showed the same tendency as that of the dose rate. The fallout of Cs for 1 month from March 15 to April 15 was about 120 times higher than that in May 1986 after the Chernobyl accident. The internal dose by inhalation was estimated from the airborne concentration observed.
Furuta, Sadaaki; Sumiya, Shuichi; Watanabe, Hitoshi; Nakano, Masanao; Imaizumi, Kenji; Takeyasu, Masanori; Nakada, Akira; Fujita, Hiroki; Mizutani, Tomoko; Morisawa, Masato; et al.
JAEA-Review 2011-035, 89 Pages, 2011/08
As a correspondence to the accident at the Fukushima Daiichi Nuclear Power Plant, the environmental radiation monitoring was performed at the Nuclear Fuel Cycle Engineering Laboratories, JAEA. This report presented the measurement results of ambient radiation dose rate, radioactivity concentration in the air and radioactivity concentration in fallout and meteorological observation result until May 31, 2011. The ambient radiation dose rate increased, with the peak dose rate of several thousand nGy/h at 7 o'clock in March 15, at 5 o'clock in March 16, and at 4 o'clock in March 21. The variation on the radioactivity concentration in the air and in fallout showed the almost same tendency as that of the dose rate. The concentration ratio of I-131/Cs-137 in the air increased to about 100. The dose was estimated resulting from internal exposure due to inhalation.
Endo, Kuniaki; Momose, Takumaro; Furuta, Sadaaki
Radiation Protection Dosimetry, 146(1-3), p.119 - 122, 2011/07
Momose, Takumaro; Kurihara, Osamu; Takada, Chie; Furuta, Sadaaki
Proceedings of 1st International Symposium on Radiation Emergency Medicine at Hirosaki University, p.65 - 72, 2010/07
The basic principle of radiation control at plutonium facility such as characteristics of plutonium and relevant radionuclide which are operated in nuclear fuel cycle facilities is introduced and potential radioactive contaminations in accident is discussed. As a practice, decontamination procedure of skin at Tokai Reprocessing Plant, some of the operating principles and applications of various radiation detection and measurement instruments for contamination control and occupational monitoring for internal contamination are introduced. Special methods of measurement for alpha emitters for performing radiological monitoring such as radio autography of plutonium contamination on smear samples, nasal swab sampling and measurement, in vivo and in vitro analysis for plutonium and uranium have been improved and proven. The internal dose calculation code was originally developed in order to estimate retrospectively in case of accidental intake of plutonium.
Sanada, Yukihisa; Tsujimura, Norio; Shimizu, Yoshio; Izaki, Kenji; Furuta, Sadaaki
Journal of Nuclear Science and Technology, 45(Suppl.5), p.74 - 77, 2008/06
The purpose of this study is the establishment of the determination procedures for the placements of CAAS detectors in PCDF. The dose of detection point was evaluated the simple equation which was formulated in calculated factors by MCNP and ANISN. When the alarm trip point was 2.0 mGy/h, the detection area was covered 30 m distances from the equipment to the CAD and 100 cm concrete shielding. This result will be reflected in the determination of the CAD placements and three CADs were placed in PCDF.
Sanada, Yukihisa; Kobayashi, Hirohide; Furuta, Sadaaki; Nemoto, Kazuhiko*; Kawai, Keiichi*; Hashimoto, Tetsuo*
Radioisotopes, 55(12), p.727 - 734, 2006/12
The purpose of this study is to develop new measurement methods of radon progenies that discharged alpha-ray focused on pulse time interval. It is calculated that a delayed coincidence method, time-interval-analysis (TIA), has been applied to decay events on the microsecond time-scale (164microsecond). The measurement system with silicon detectors was produced and examined a basic performance of the system by using Th electrodeposited sources. This system was designed that it have shorter dead times. The results were as follows. (1) The theory of measurement Po using TIA methods was established. (2) Development of the system that measured Po. (3) Suggested that methods to examine a basic performance by using Th electrodeposited sources. It is scheduled to examine the method of subtracting the progenies of the thorium series, and to reflect this system in an actual work of radiation control in the future.
Nakano, Masanao; Takeishi, Minoru; Furuta, Sadaaki
Proceedings of 2nd Asian and Oceanic Congress Radiological Protection (AOCRP-2) (CD-ROM), p.795 - 799, 2006/10
In order to assess the worldwide and long-term effects from nuclear facilities, LAMER (Long-term Assessment ModEl for Radioactivity in the oceans) has been developed. As a part of LAMER, an advection-diffusion-scavenging model incorporated into the OGCM concerned the Japan Sea has been developed and validated by calculating Cs and Pu water profiles in the Japan Sea and comparing them with experimental data. The concentrations of Cs and Pu have generally shown reasonable agreement between calculated and observed data. The best agreement between the experimental and calculated water profiles in the Japan Sea was obtained with the horizontal and vertical diffusion coefficients of 310 cm s and 0.3 cm s, respectively. The simulation in this study make them sure the quantitative origins and behaviours of Cs and Pu in the Japan Sea. The behaviours of Cs and Pu in the Japan Sea have been much different from the behaviours in the Pacific Ocean.
Furuta, Sadaaki; Miyabe, Kenjiro
Proceedings of 2nd Asian and Oceanic Congress Radiological Protection (AOCRP-2) (CD-ROM), p.928 - 932, 2006/10
In 1972, production of nuclear fuels for experimental fast breeder reactor "JOYO" started at MOX fuel fabrication facilities in the Nuclear Fuel Cycle Engineering Laboratories of JAEA. And in 1977 Tokai reprocessing plant "TRP" was launched as the first nuclear reprocessing plant in Japan with a capacity of 0.7tU/day spent fuel, and successfully reprocessed 1,116tU fuel mainly spent by light water reactor up to March 2006. A lot of other nuclear facilities associated with them are located at the same Laboratories' site. A feature of radiation protection and its recent relevant researches at the Laboratories are described in this paper.
; Ishimori, Yuu; Furuta, Sadaaki;
AOCRP-1, 0 Pages, 2002/00
Ishimori, Yuu; Furuta, Sadaaki;
Dai-8-Kai Kokusai Akuchinido Kaigi, 0 Pages, 2002/00
Furuta, Sadaaki; Ito, Kimio; Ishimori, Yuu
International Workshop on Distribution and Specia, 0 Pages, 2002/00
Furuta, Sadaaki; Ito, Kimio; Ishimori, Yuu
International Workshop on Distribution and Speciat, 0 Pages, 2002/00
Ishimori, Yuu; Furuta, Sadaaki
Proceedings of International Conference on Radioactivity in the Environment, 0 Pages, 2002/00