Measurement of air dose rates over a wide area around the Fukushima Dai-ichi Nuclear Power Plant through a series of car-borne surveys

Ando, Masaki; Nakahara, Yukio; Tsuda, Shuichi; Yoshida, Tadayoshi; Matsuda, Norihiro; Takahashi, Fumiaki; Mikami, Satoshi; Kinouchi, Nobuyuki; Sato, Tetsuro*; Tanigaki, Minoru*; et al.

Journal of Environmental Radioactivity, 139, p.266 - 280, 2015/01

https://doi.org/10.1016/j.jenvrad.2014.05.014

A series of car-borne surveys using the KURAMA and KURAMA-II systems was conducted in a wide area in eastern Japan from June 2011 to December 2012 to evaluate the distribution of air dose rates around the Fukushima Dai-ichi Nuclear Power Plant, and to determine the time-dependent trend of decrease in air dose rates. An automated data processing system was established, which enables analyses of large amounts of data obtained with the use of about 100 units of the measurement system in a short time. The initial data for studying the migration status of radioactive cesium was obtained in the first survey, followed by the other car-borne surveys having wider measurement ranges. Comparing the measured air dose rates obtained in each survey, it was found that the decreasing trend of air dose rates measured through car-borne surveys was larger than that expected from the physical decay of radioactive cesium and that measured using NaI (Tl) survey meters around the road.

Renewal of centralized radioactivity measurement system for radiation control

Kawasaki, Katsuya; Mochizuki, Kaoru*; Suzuki, Takehiko; Kinouchi, Nobuyuki

JAERI-Tech 2004-070, 50 Pages, 2004/12

JAERI-Tech-2004-070.pdf:18.19MB

The centralized radioactivity measurement system has been used to carry out intensively measurements of a large number and variety of samples that are necessary for the control of radioactivity in the facilities of the JAERI Tokai Establishment and its environment. The operation of the system started in 1981, and presently the system processes more than 20,000 samples a year. However, the computers of the system have aged so much that the manufacturer's support and stable operation are no longer sure. Therefore, we renewed and restructured the computer system in 2003. A client-server system was adopted in the new system. The information of samples can be registered through the intranet. The clients can also confirm the progress of processing of their samples and browse the analytical results from their own computers. The renewed system can provide some convenience functions to the clients.

A Simple method evaluating collection performance of air filters with imaging plates

Kinouchi, Nobuyuki; Oishi, Tetsuya; Yoshida, Makoto

Radioisotopes, 51(7), p.266 - 271, 2002/07

https://doi.org/10.3769/radioisotopes.51.266

Collection performance such as collection efficiency and surface colletion efficiency is considerably important in order to select a suitable filter for the measurement of the concentrations of airborne radioactive particles. A simple method with imaging plates is proposed to evaluate the collection performance of air filters. By comparing the collection performance of some filters with natural airborne radioactivity as a test aerosol, it was confirmed that the method could reliably evaluate the collection performance of filters.

Simulation of the background for detection system in the indoor environments of concrete buildings

Tsutsumi, Masahiro; Oishi, Tetsuya; Kinouchi, Nobuyuki; Sakamoto, Ryuichi; Yoshida, Makoto

Journal of Nuclear Science and Technology, 38(12), p.1109 - 1114, 2001/12

https://doi.org/10.3327/jnst.38.1109

In order to predict the indoor background spectra to gamma detection systems, the gamma radiation field in a concrete building is studied by the Monte Carlo simulations. The parameters of wall thickness, room shape and dimensions were considered in the modeling. The indoor source geometry was simulated by a spherical layer model with the intention of easy and effective calculations. The model was applied to an unshielded germanium detector and the detection system with a more complex shielding configuration. As the results, we found that the indoor radiation field in concrete buildings can be predicted well with the source geometry of a spherical concrete layer of 25cm thickness and with the source of the natural major three components of the U series, Th series and K that are homogeneously distributed. The simulation model is useful for designing and optimizing gamma detection systems or shielding assemblies.

Uniformity of beta-ray plane sources for the calibration of surface contamination monitors

Kinouchi, Nobuyuki; Oishi, Tetsuya; Yoshida, Makoto

Radioisotopes, 50(5), p.183 - 189, 2001/05

https://doi.org/10.3769/radioisotopes.50.183

no abstracts in English

Selection of filter media in alpha air monitors for emergency environmental monitoring

Kinouchi, Nobuyuki; Oishi, Tetsuya; Noguchi, Hiroshi; Kato, Shohei; Ishizawa, Masato*

Proceedings of 10th International Congress of the International Radiation Protection Association (IRPA-10) (CD-ROM), 4 Pages, 2000/05

no abstracts in English

A Database on tritium behavior in the chronic HT release experiment, 1; Meteorological data and tritium concentrations in air and soil

Noguchi, Hiroshi; Yokoyama, Sumi; Fukatani, S.*; Kinouchi, Nobuyuki; Murata, Mikio; Amano, Hikaru; Atarashi-Andoh, Mariko

JAERI-Data/Code 99-022, 125 Pages, 1999/03

JAERI-Data-Code-99-022.pdf:6.76MB

no abstracts in English

Test of dust scattering caused by dumping of concrete materials

Kinouchi, Nobuyuki; Kato, Shohei

KURRI-KR-30, p.12 - 19, 1998/00

no abstracts in English

Tritium behavior on a cultivated plot in the 1994 chronic HT release experiment at Chalk River

Noguchi, Hiroshi; Yokoyama, Sumi; Kinouchi, Nobuyuki; Murata, Mikio; Amano, Hikaru; Atarashi, Mariko; Ichimasa, Yusuke*; Ichimasa, Michiko*

Fusion Technology, 28, p.924 - 929, 1995/10

no abstracts in English

HTO emission from contaminated surfaces and distribution in the environmental media; Summary of data collected during field study in Canada in July 1992, 1

Murata, Mikio; Kinouchi, Nobuyuki; Yokoyama, Sumi

JAERI-M 94-065, 93 Pages, 1994/03

JAERI-M-94-065.pdf:2.53MB

no abstracts in English