Periez, R.*; Brovchenko, I.*; Jung, K. T.*; Kim, K. O.*; Liptak, L.*; Little, A.*; Kobayashi, Takuya; Maderich, V.*; Min, B. I.*; Suh, K. S.*
Journal of Environmental Radioactivity, 261, p.107138_1 - 107138_8, 2023/05
Lagrangian models present several advantages over Eulerian models to simulate the transport of radionuclides in the aquatic environment in emergency situations. A radionuclide release is simulated as a number of particles whose trajectories are calculated along time and thus these models do not require a spatial discretization. In this paper we investigate the dependence of a Lagrangian model output with the grid spacing which is used to calculate concentrations from the final distribution of particles, with the number of particles in the simulation and with the interpolation schemes which are required because of the discrete nature of the water circulation data used to feed the model.
Onishi, Takashi; Maeda, Koji; Katsuyama, Kozo
Journal of Nuclear Science and Technology, 58(4), p.383 - 398, 2021/04
Oba, Takashi*; Ishikawa, Tetsuo*; Nagai, Haruyasu; Tokonami, Shinji*; Hasegawa, Arifumi*; Suzuki, Gen*
Scientific Reports (Internet), 10(1), p.3639_1 - 3639_11, 2020/02
Internal doses of residents after the Fukushima Daiichi Nuclear Power Station accident have been reconstructed. In total 896 behaviour records in the Fukushima Health Management Survey were analysed to estimate thyroid doses via inhalation, using a spatiotemporal radionuclides concentration database constructed by atmospheric dispersion simulations. After a decontamination factor for sheltering and a modifying factor for the dose coefficient were applied, estimated thyroid doses were close to those estimated on the basis of direct thyroid measurement. The median and 95th percentile of thyroid doses of 1-year-old children ranged from 1.2 to 15 mSv and from 7.5 to 30 mSv, respectively.
Kobayashi, Takuya; Chino, Masamichi; Togawa, Orihiko
Journal of Nuclear Science and Technology, 43(5), p.569 - 575, 2006/05
A dissolved radionuclide migration code system that consists of a ocean circulation model, Princeton Ocean Model, and a particle random-walk model, SEA-GEARN, has been developed. The oceanic migration of Cs discharged from a nuclear submarine in a hypothetical accident at the Tsushima Strait was calculated in the southwestern area of the Japan Sea as a model application. The calculations for instantaneous releases every 10 days were carried out for one year to study the seasonal differences of migration process of the dissolved radionuclides. The migration tendencies of dissolved radionuclides were divided into two patterns. For the releases started from January to September, all of the high concentration areas migrated to the northeast along the coastline of the Main Island of Japan from the release point. As for the releases from October to December, some high concentrations areas migrated to the west from the release point and the concentrations of Cs along the coastline of the Main Island of Japan were comparatively low.
Yokoyama, Sumi; Sato, Kaoru; Noguchi, Hiroshi; Tanaka, Susumu; Iida, Takao*; Furuichi, Shinya*; Kanda, Yukio*; Oki, Yuichi*; Kaneto, Taihei*
Radiation Protection Dosimetry, 116(1-4), p.401 - 405, 2005/12
The physicochemical property of radionuclides suspended in the air is an important parameter to evaluate internal doses due to the inhalation of the airborne radionuclides and to develop the air monitoring system in high-energy proton accelerator facilities. This study focuses on the property of radioactive airborne chlorine (Cl and Cl) and sulfur (S) formed from Ar gas by irradiation with high-energy neutrons. As a result of the irradiation to a mixture of Ar gas and dry air, Cl and Cl existed as non-acidic gas and S was present as acidic gas. Further, it was found that in the high-energy neutron irradiation to aerosol containing-Ar gas, the higher the amount of radioactive aerosols becomes, the lower that of radioactive acidic gas becomes.
Shinohara, Nobuo; Asano, Yoshie; Hirota, Naoki*; Hokida, Takanori; Inoue, Yoji; Kumata, Masahiro; Nakahara, Yoshinori*; Oda, Tetsuzo*; Uchikoshi, Takako*; Yamamoto, Yoichi
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 3 Pages, 2005/10
Research activities of JAERI related to the CTBT verification regime are presented in the International Conference. The subjects of this presentation are (1) an overview of the CTBT verification regime, (2) construction and operation of the radionuclide monitoring stations of Okinawa (RN37) and Takasaki (RN38) and the certified radionuclide laboratory (RL11), and (3) preparation of the National Data Center at Tokai (JAERI NDC) for radionuclide data. The RN38 station has been certified by the CTBTO/PrepCom and sending the measured data every day. The infrastructures and operational manuals for RN37 and RL11 are now preparing for their operations. The JAERI NDC has experimentally analyzed and evaluated the radionuclide data from all over the world through International Data Center (IDC). As an example of the JAERI NDC works, atmospheric dispersion backtracking system has been developing by using WSPEEDI (Worldwide Version of System for Prediction of Environmental Emergency Dose Information) code to estimate a source location of radionuclide release by nuclear explosion/accident.
Imaizumi, Hirobumi; Ban, Yasutoshi; Sato, Makoto; Asakura, Toshihide; Morita, Yasuji
JAERI-Research 2005-025, 94 Pages, 2005/09
Washing properties of n-butylamine compounds, which are decomposable by burning or electrolysis, for dibutylphosphoric acid (DBP) and Zr in real and simulated degraded solvents have been investigated. In experiments with simulated degraded solvents, basic properties of n-butylamine compounds for washing DBP and Zr were examined and optimum condition was obtained. It was confirmed from the simulated degraded solvent washing tests that 0.25 mol/dm n-butylamine oxalate of pH 2 could effectively remove Zr from the degraded solvent and the solution of pH 4 was effective for DBP, 95% removal of Zr and DBP were obtained by batch washing. The validity of n-butylamine as a degraded solvent wash reagent was shown by the washing test for real degraded solvent that was performed by continuous counter current flow using a miniature mixer-settler. The present study was carried out as a part of the joint study "Research and Development of Process Elements in an Advanced Aqueous Reprocessing" between Japan Nuclear Cycle Development Institute and JAERI.
Tran, V. H.; Satoh, Daiki; Takahashi, Fumiaki; Tsuda, Shuichi; Endo, Akira; Saito, Kimiaki; Yamaguchi, Yasuhiro
JAERI-Tech 2004-079, 37 Pages, 2005/02
no abstracts in English
Ito, Toshimichi; Aramaki, Takafumi*; Otosaka, Shigeyoshi; Suzuki, Takashi; Togawa, Orihiko; Kobayashi, Takuya; Kawamura, Hideyuki; Amano, Hikaru; Senju, Tomoharu*; Chaykovskaya, E. L.*; et al.
Journal of Nuclear Science and Technology, 42(1), p.90 - 100, 2005/01
During 1996-2002, a wide-area research project on anthropogenic radionuclides was done in the Japanese and Russian EEZ of the Japan Sea to investigate their migration. As the results of expeditions in 2001 and 2002, (1) the concentrations and distributions of radionuclides are similar to the results of previous, (2) inventories of these radionuclides indicate accumulation in the Japan Sea seawater compared to the amounts supplied by global fallout, (3) Sr and Cs concentrations in intermediate layer show temporal variations, and 4) the variations may reflect the water mass movement in upper part of the Japan Sea.
Fuel Safety Research Laboratory
JAERI-Review 2004-021, 226 Pages, 2004/10
Fuel Safety Research Meeting 2004, which was organized by Japan Atomic Energy Research Institute, was held on March 1-2, 2004 at Toranomon Pastoral, Tokyo. Purposes of the meeting are to present and discuss results of experiments and analyses on reactor fuel safety and to exchange views and experiences among the participants. Technical topics of the meeting covered status of fuel safety research activities, fuel behavior under RIA and LOCA conditions, high burnup fuel behavior, and radionuclides release under severe accident conditions. This proceeding contains all the papers presented in the meeting.
Amano, Hikaru; Ikeda, Hiroshi*; Sasaki, Toshihisa*; Matsuoka, Shungo*; Kurosawa, Naohiro*; Takahashi, Tomoyuki*; Uchida, Shigeo*
KEK Proceedings 2003-11, p.239 - 244, 2003/11
A Code MOGRA (Migration Of GRound Additions) is a migration prediction code for toxic ground additions including radioactive materials in a terrestrial environment, which consists of computational codes that are applicable to various evaluation target systems, and can be used on personal computers. The computational code has the dynamic compartment analysis block at its core, the graphical user interface (GUI) for model formation, computation parameter settings, and results displays. The code MOGRA has varieties of databases, which is called MOGRA-DB. Another additional code MOGRA-MAP can take in graphic map and calculate the square measure about the target land.
Amano, Hikaru; Uchida, Shigeo*
JAERI-Conf 2003-010, 394 Pages, 2003/09
The International Symposium : Transfer of Radionuclides in Biosphere, Prediction and Assessment was held at Mito on the 18th and 19th of Dec. 2002. This Symposium was organized by the Interchange Committee on Radionuclide Transfer in Soil Ecosphere. This project is the 3rd Phase Crossover Research, which is engaged in cooperation with five organizations:JAERI, MRI, NIRS, RIKEN and IES. The main objective of this symposium is to discuss and exchange recent findings and ideas in the area of the behavior and transfer of radionuclides in biosphere. One of the important topics in this symposium is to discuss a suitable transfer model and transfer parameters which may be adapted for Southeast Asian countries including Japan, as environmental conditions and foodstuffs in this region are significantly different from those in Europe and North America. The symposium consisted of 12 invited lectures and 44 poster presentations. The 120 participants attended the symposium, including 19 foreigners coming from 12 countries.
Endo, Akira; Sato, Kaoru; Noguchi, Hiroshi; Tanaka, Susumu; Iida, Takao*; Furuichi, Shinya*; Kanda, Yukio*; Oki, Yuichi*
Journal of Radioanalytical and Nuclear Chemistry, 256(2), p.231 - 237, 2003/05
Size distributions of Cl, Cl, Br and Br aerosols generated by irradiations of argon and krypton gases containing di-octyl phthalate (DOP) aerosols with 45MeV and 65MeV quasi-monoenergetic neutrons were measured to study the formation mechanism of radioactive particles in high energy radiation fields. Effects of the size distribution of the radioactive aerosols on the size of added DOP aerosols, the energy of irradiation neutrons and the kinds of nuclides were studied. The observed size distributions of the radioactive particles were explained by attachment of the radioactive atoms generated by the neutron-induced reactions to the DOP aerosols.
Ueno, Takashi; Matsunaga, Takeshi; Amano, Hikaru; Tkachenko, Y.*; Kovalyov, A.*; Sukhoruchkin, A.*; Derevets, V.*
JAERI-Data/Code 2002-024, 414 Pages, 2003/01
This report is a compilation of the shared data derived from the environmental monitoring by RADEK (The state Enterprise for Region Monitoring of Environment and Dosimetric Control of Ukraine) and the record of environmental characteristics derived from field observations during a research project (1992-1999) between JAERI (Japan Atomic Energy Research Institute) and CHESCIR (Chernobyl Science and Technology Centre for International Research). The compiled data in this report are especially related to one particular research subject (Subject-3) of the project on the migration of radionuclides released into the terrestrial and aquatic environments after a nuclear accident. The present report shows the basis of published works concerning Subject-3.
Kobayashi, Takuya; Lee, S.; Chino, Masamichi
Journal of Nuclear Science and Technology, 39(2), p.171 - 179, 2002/02
A three-dimensional model system was developed to predict oceanic dispersions of radionuclides released into the eastern area of Shimokita Peninsula. This system is a combination of the Princeton Ocean Model (POM) for predicting ocean currents and a particle random walk model for oceanic dispersion of radionuclides. The model was verified by using measured currents, temperature and salinity at the coastal area of Shimokita, Aomori-ken, Japan, where a nuclear fuel reprocessing plant is under construction. The results obtained from simulations area as follows; (1) Wind and the Tsugaru Warm Current entering into the objective region through the Tsugaru Strait significantly affect the structure of current over the region. (2) POM can represent seasonal variations of the Tsugaru Warm Current well with hypothetical oceanographic data. The calculation succeeded to reproduce the coastal mode from winter to spring and the gyre mode from summer to autumn.
Tsutsumi, Masahiro; Oishi, Tetsuya; Kinouchi, Nobuyuki; Sakamoto, Ryuichi; Yoshida, Makoto
Journal of Nuclear Science and Technology, 38(12), p.1109 - 1114, 2001/12
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.
Kudo, Tamotsu; Hidaka, Akihide; Nakamura, Takehiko; Uetsuka, Hiroshi
Journal of Nuclear Science and Technology, 38(10), p.910 - 911, 2001/10
This article describes the effects of system pressure on the cesium release obtained in the first two tests of radionuclides release from irradiated fuel, VEGA-1 and VEGA-2, which were conducted at the same maximum temperature of 2773K and different system pressures. The fractional releases of Cs in VEGA-2 test at 1.0MPa were smaller than those in VEGA-1 test at atmospheric pressure. In order to quantify the difference of the release rate in the two tests due to the pressure, the release rate coefficients of Cs were evaluated. The Cs release rate coefficient in VEGA-2 was smaller by a factor of about 2.8 than that in VEGA-1 at temperature above about 1900K.
Kanda, Yukio*; Oki, Yuichi*; Endo, Akira; Numajiri, Masaharu*; Kondo, Kenjiro*
Journal of Radioanalytical and Nuclear Chemistry, 247(1), p.25 - 31, 2001/01
no abstracts in English
Nihon Dojo Hiryo Gaku Zasshi, 71(6), p.928 - 929, 2000/11
no abstracts in English
Nagao, Seiya; Matsunaga, Takeshi; Fujitake, Nobuhide*; Amano, Hikaru
Proceedings of the International Workshop on Distribution and Speciation of Radionuclides in the Environment, p.162 - 168, 2000/00
no abstracts in English