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Journal Articles

Modelling of marine radionuclide dispersion in IAEA MODARIA program; Lessons learnt from the Baltic Sea and Fukushima scenarios

Periez, R.*; Bezhenar, R.*; Brovchenko, I.*; Duffa, C.*; Iosjpe, M.*; Jung, K. T.*; Kobayashi, Takuya; Lamego, F.*; Maderich, V.*; Min, B. I.*; et al.

Science of the Total Environment, 569-570, p.594 - 602, 2016/11

https://doi.org/10.1016/j.scitotenv.2016.06.131

Times Cited Count：26 Percentile：63.89(Environmental Sciences)

State-of-the art dispersion models were applied to simulate $^{137}$ Cs dispersion from Chernobyl Nuclear Power Plant disaster fallout in the Baltic Sea and from Fukushima Daiichi Nuclear Plant releases in the Pacific Ocean after the 2011 tsunami. Models were of different nature, from box to full three-dimensional models, and included water/sediment interactions. Agreement between models was very good in the Baltic. In the case of Fukushima, results from models could be considered to be in acceptable agreement only after a model harmonization process consisting of using exactly the same forcing (water circulation and parameters) in all models. It was found that the dynamics of the considered system (magnitude and variability of currents) was essential in obtaining a good agreement between models. The difficulties in developing operative models for decision-making support in these dynamic environments were highlighted.

Journal Articles

Development of a long-range atmospheric transport model for nuclear emergency and its application to the Chernobyl nuclear accident

Terada, Hiroaki; Chino, Masamichi

Proceedings of 2nd International Conference on Radioactivity in the Environment, p.15 - 18, 2005/10

The previous version of Worldwide version of System for Prediction of Environmental Emergency Dose Information (WSPEEDI) has been composed of mass-consistent wind field model WSYNOP and particle dispersion model GEARN. Because WSYNOP has no capability to predict meteorological fields, its accuracy and resolution depends on meteorological input data, and it is impossible to treat physical processes realistically. To improve these problems, an atmospheric dynamic model MM5 is introduced and applied to the Chernobyl accident for the verification. Two calculation cases are conducted, CASE-1 a calculation for European region Domain-1, and CASE-2 a domain nesting calculation for Domain-1 and the region around Chernobyl Domain-2. The air concentration and surface deposition of $^{137}$ Cs calculated by CASE-1 agree well with the measurements by statistical analysis and comparison for the horizontal distribution. In the result of CASE-2, the detailed distribution of surface $^{137}$ Cs deposition around Chernobyl which was impossible to calculate in CASE-1 is predicted with high accuracy.

Journal Articles

Improvement of Worldwide version of System for Prediction of Environmental Emergency Dose Information (WSPEEDI), 2; Evaluation of numerical models by $^{137}$ Cs deposition due to the Chernobyl nuclear accident

Terada, Hiroaki; Chino, Masamichi

Journal of Nuclear Science and Technology, 42(7), p.651 - 660, 2005/07

https://doi.org/10.3327/jnst.42.651

Times Cited Count：18 Percentile：74.92(Nuclear Science & Technology)

The prediction performance of WSPEEDI (Worldwide version of System for Prediction of Environmental Emergency Dose Information), which consists of the atmospheric dynamic model MM5 and the Lagrangian particle dispersion model GEARN-new, is evaluated by measurements of precipitation and surface deposition of $^{137}$ Cs over Europe during the Chernobyl accident. It is concluded that MM5/GEARN-new can predict $^{137}$ Cs deposition distribution with good accuracy when accurate precipitation is predicted by using a explicit scheme on cloud microphysics with ice phase processes. High-resolutional calculation is also conducted for the area surrounding Chernobyl by a nesting method. MM5/GEARN-new can predict quite a realistic distribution of $^{137}$ Cs deposition around Chernobyl which was not calculated by the previous version.

Journal Articles

Model testing using data on $^{137}$ Cs from Chernobyl fallout in the Iput River catchment area of Russia

Thiessen, K. M.*; Sazykina, T. G.*; Apostoaei, A. I.*; Balonov, M. I.*; Crawford, J.*; Domel, R.*; Fesenko, S.*; Filistovic, V.*; Galeriu, D.*; Homma, Toshimitsu; et al.

Journal of Environmental Radioactivity, 84(2), p.225 - 244, 2005/00

https://doi.org/10.1016/j.jenvrad.2004.10.016

Times Cited Count：7 Percentile：17.22(Environmental Sciences)

Data collected following the Chernobyl accident in 1986 have provided a unique opportunity to test the reliability of computer models for contamination of terrestrial and aquatic environments. The Iput River scenario was used by the Dose Reconstruction Working Group of BIOMASS. The test area was one of the most highly contaminated areas in Russia following the accident, with an average contamination density of $^{137}$ Cs of 800, 000 Bq m $^{-2}$ and localized contamination up to 1,500,000 Bq m $^{-2}$ , and a variety of countermeasures that were implemented in the test area had to be considered in the modelling exercise. Difficulties encountered during the exercise included averaging of data to account for uneven contamination of the test area, simulating the downward migration and decrease in bioavailability of $^{137}$ Cs in soil, and modelling the effectiveness of countermeasures. The accuracy of model predictions is dependent at least in part on the experience and judgment of the participant in interpretation of input information, selection of parameter values, and treatment of uncertainties.

Journal Articles

Association of dissolved radionuclides released by the Chernobyl accident with colloidal materials in surface water

Matsunaga, Takeshi; Nagao, Seiya*; Ueno, Takashi; Takeda, Seiji; Amano, Hikaru; Tkachenko, Y.*

Applied Geochemistry, 19(10), p.1581 - 1599, 2004/10

https://doi.org/10.1016/j.apgeochem.2004.02.002

Times Cited Count：35 Percentile：55.27(Geochemistry & Geophysics)

The association of dissolved $^{90}$ Sr, $^{239,240}$ Pu and $^{241}$ Am with natural colloids was investigated in surface waters in the Chernobyl nuclear accident area by means of ultrafiltration. Results suggest that Pu and Am isotopes were preferentially associated with dissolved humic substances (HS) of high molecular size. A model calculation of the complexation of Pu and Am with HS also supported the above. This study has expanded our understanding of the general role of natural organic colloids in dictating the chemical form of actinides in the surface aquatic environment.

Journal Articles

Improvement of Worldwide Version of System for Prediction of Environmental Emergency Dose Information (WSPEEDI), 1; New combination of models, atmospheric dynamic model MM5 and particle random walk model GEARN-new

Terada, Hiroaki; Furuno, Akiko; Chino, Masamichi

Journal of Nuclear Science and Technology, 41(5), p.632 - 640, 2004/05

https://doi.org/10.3327/jnst.41.632

Times Cited Count：22 Percentile：79.11(Nuclear Science & Technology)

The new version of WSPEEDI (Worldwide version of System for Prediction of Environmental Emergency Dose Information) is developed by introducing the combination of models, the atmospheric dynamic model MM5 and the Lagrangian particle dispersion model GEARN-new to improve the prediction capability. One of the improvements by the new system is that Environmental contaminations in multi domains are predicted simultaneously, and the other is that more precise physical processes are considered by using predicted meteorological conditions with high resolution in time and space. The performance of the system is evaluated for the test calculations of hypothetical nuclear accident in the East Asia region and the Chernobyl accident. The results of test calculation in East Asia seem to be reasonable and the calculated surface air concentrations of $^{137}$ Cs from Chernobyl show good agreement with measurements.

Journal Articles

Conversion factors for a mobile survey method by car in the Chernobyl area

Sakamoto, Ryuichi; Saito, Kimiaki

Radiation Protection Dosimetry, 106(2), p.165 - 175, 2003/11

https://doi.org/10.1093/oxfordjournals.rpd.a006346

Times Cited Count：6 Percentile：41.75(Environmental Sciences)

Conversion factors for the purpose of mobile survey by car were evaluated quantitatively to convert the gamma ray dose rate level measured on the road to that in the typical land-use around the road by simulation calculations. In the calculation, the width and the surrounding area of the road were assumed as being the real environment contaminated by $^{137}$ Cs nuclide. The calculated conversion factors indicated to agree with the conversion factors measured in the field within the accuracy of 20%.

Journal Articles

Impressions on the 51st session of UNSCEAR

Yoshizawa, Michio

Hoshasen Kagaku, 46(6), p.184 - 187, 2003/06

no abstracts in English

JAEA Reports

Environmental monitoring data around the Chernobyl Nuclear Power Plant used in the cooperative research project between JAERI and CHESCIR (Ukraine) (Cooperative research)

Ueno, Takashi; Matsunaga, Takeshi; Amano, Hikaru; Tkachenko, Y.*; Kovalyov, A.*; Sukhoruchkin, A.*; Derevets, V.*

JAERI-Data/Code 2002-024, 414 Pages, 2003/01

JAERI-Data-Code-2002-024.pdf:15.11MB

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.

Journal Articles

Model testing using data on $^{137}$ Cs from Chernobyl fallout in the Iput River catchment area of Russia

Thiessen, K. M.*; Sazykina, T. G.*; Apostoaei, A. I.*; Balonov, M.*; Crawford, J.*; Domel, R.*; Fesenko, S.*; Filistovic, V.*; Galeriu, D.*; Homma, Toshimitsu; et al.

Proceedings from the International Conference on Radioactivity in the Environment, p.317 - 320, 2002/09

no abstracts in English

Journal Articles

Accumulation and potential dissolution of Chernobyl-derived radionuclides in river bottom sediments

Sanada, Yukihisa*; Matsunaga, Takeshi; Yanase, Nobuyuki; Nagao, Seiya; Amano, Hikaru; Takada, Hideshige*; Tkachenko, Y.*

Applied Radiation and Isotopes, 56(5), p.751 - 760, 2002/04

https://doi.org/10.1016/S0969-8043(01)00274-3

Times Cited Count：14 Percentile：65.6(Chemistry, Inorganic & Nuclear)

Areas contaminated with radionuclides from the Chernobyl nuclear accident have been identified in Pripyat River near the Chernobyl Nuclear Power Plant. The bottom sediments contained $^{137}$ Cs (10 $^{5}$ - 10 $^{6}$ Bq/m $^{2}$ ) within 0-30 cm depth, which is comparable to the ground soil of in the vicinity of the nuclear power plant (the Exclusion Zone). The sediments also accumulated $^{90}$ Sr (10 $^{5}$ Bq/m $^{2}$ ), $^{239,240}$ Pu (10 $^{4}$ Bq/m $^{2}$ ), $^{241}$ Am (10 $^{4}$ Bq/m $^{2}$ ) derived from the accident.The comparison of these inventories with those of the released radionuclides at the accident and the experimental analysis using the selective sequential extraction of the radionuclides in the sediments suggest that the potential mobility of $^{137}$ Cs and $^{239,240}$ Pu is low compared with $^{90}$ Sr in the bottom sediment, while the potential dissolution of $^{90}$ Sr from the river bottom sediment should be taken into account with respect to the long-term radiological influence on the aquatic environment.

Journal Articles

Study on the measurements and evaluation of environmental external exposure after the nuclear accident

Sakamoto, Ryuichi; Saito, Kimiaki; Tsutsumi, Masahiro; Nagaoka, Toshi

Hoken Butsuri, 36(4), p.297 - 307, 2001/12

https://doi.org/10.5453/jhps.36.297

There are many factors which affect external exposure in contaminated area: distributions of fallout, compositions of radioactive nuclides, soil conditions, depth profile of radioactivity in soil, rain fall, snow cover, radioactive decay, shielding effects of houses and other structures, de-contamination measures, and the 'occupancy factor' which accounts for the fraction of time that inhabitants spend in different locations. In this study, several important issues concerning these factors have been investigated using field measurements and computational simulations since 1992 in the Chernobyl area. The objectives of the study were: (1) The development of a mobile survey method to collect radiation data of the contaminated area over a wide area in a short time; (2) The verification of a method to infer external doses to the population; (3) The provision of basic data used for the evaluation of external dose due to gamma ray using a Monte Carlo simulation method. (4) Characteristics of the radiation fields in contaminated area. In this report, the results were summerized.

JAEA Reports

A Review on studies of the transport and the form of radionuclides in the fluvial environment

Matsunaga, Takeshi

JAERI-Review 2001-018, 121 Pages, 2001/06

JAERI-Review-2001-018.pdf:5.95MB

The present report reviews a series of studies conducted in JAERI which have dealt with the behavior of atmospherically-derived radionuclides in a fluvial environment. The studies cited here firstly include investigations of the evaluation of the transport rate of the atmospherically-derived 137Cs, 210Pb and 7Be from the ground via a river to the downstream areas where the affected water is consumed. The studies validated i) the importance of suspended particulate materials in the fluvial discharge of those radionuclides, and ii) a methodology to estimate the discharge of those radionuclides. Secondly, studies in rivers and lakes in the vicinity of the Chernobyl Nuclear Power Plant revealed the role of natural dissolved organics in affecting the dissolution and transport of 239,240Pu, 241Am through complexation to form soluble species with the aid of a chemical equilibrium model The same sort of a model was also applied successfully for the behavior of iron and manganese (hydr)oxides in river recharged aquifers which could bear riverborne radionuclides.

Journal Articles

Relationships between dose rates measured 1m above ground level and the $^{137}$ Cs depth distribution in the Chernobyl grounds

Sakamoto, Ryuichi; Saito, Kimiaki; Tsutsumi, Masahiro; Nagaoka, Toshi; Stolyarevsky, I.*; Glebkin, S.*; Tepikin, V.*; Arkhipov, N.*; Ramzaev, V.*; Mishine, A.*; et al.

Proceedings of 10th International Congress of the International Radiation Protection Association (IRPA-10) (CD-ROM), 5 Pages, 2000/05

no abstracts in English

Journal Articles