Development of database of dose reduction factor for reducing equivalent doses to the thyroid by implementing iodine thyroid blocking (Contract research)

Kimura, Masanori; Munakata, Masahiro; Hato, Shinji*; Kanno, Mitsuhiro*

JAEA-Data/Code 2020-002, 38 Pages, 2020/03

JAEA-Data-Code-2020-002.pdf:3.23MB

To consider the method of implementing urgent protective actions in a nuclear accident appropriately, the authors have been assessing the effects of reducing doses by taking urgent protective actions using a Level 3 Probabilistic Risk Assessment (PRA) code, the OSCAAR, developed by the JAEA. Iodine thyroid blocking is an effective urgent protective action to reduce equivalent doses to the thyroid due to inhalation of radioactive iodine. However, the timing of the administration of stable iodine (SI) is important to maximize the effectiveness for thyroidal blocking. Therefore, the careful consideration should be given to the most effective way of iodine thyroid blocking when preparing off-site emergency plans. In the present study, the authors developed a new metabolic model for thyroid by combining the respiratory tract model (Publ.66) and gastrointestinal tract model (Publ.30) of the ICRP with a metabolic model for thyroid (Johnson's model) in order to calculate the behavior of radioiodine and stable iodine in the body more realistically. The model is useful to evaluate the effect of the administration of SI for reducing equivalent doses to the thyroid depending on the its timing. We also calculated the reduction factor for equivalent doses to the thyroid in order to the thyroid by using the model, and then developed the its database for the OSCAAR. Consequently, the OSCAAR can evaluate the effectiveness for thyroidal blocking realistically and promptly.

A Compartment model of radionuclide migration in environment based on exposure pathways

Kurikami, Hiroshi; Niizato, Tadafumi; Tsuruta, Tadahiko; Kato, Tomoko; Kitamura, Akihiro; Kanno, Mitsuhiro*; Kurosawa, Naohiro*

JAEA-Research 2016-020, 50 Pages, 2017/01

JAEA-Research-2016-020.pdf:6.02MB

In this report, we developed a compartment model of radionuclide migration in environment based on exposure pathways in a river basin scale and performed a preliminary calculation. The results showed good agreement with some measurement, although the comparison of bed sediment, transportation to outer sea and to agricultural products with the measurement was not enough. We continue to validate the model.

Development of calculation code for estimating radiation dose for hypothetical accident of nuclear facility considering radioactive decay chain during atmospheric dispersion of released radionuclides

Takeyasu, Masanori; Nakano, Masanao; Sumiya, Shuichi; Nemoto, Hiromi*; Kanno, Mitsuhiro*; Kurosawa, Naohiro*

Proceedings of 3rd Asian and Oceanic Congress on Radiation Protection (AOCRP-3) (CD-ROM), 4 Pages, 2010/05

The dose to the public at hypothetical accident of nuclear facility is estimated on the basis of the method described in the Japanese meteorological guideline. However, the radioactive decay during atmospheric dispersion of released radionuclide is not considered in the calculation formula in the guideline. Therefore, when the radionuclide of the half life such as a few min is released, the dose may be excessively over-estimated. In this study, the calculation code was developed which could consider the radioactive decay of the released radionuclide and the generation of the product. The dose calculated on the basis of the developed code was compared with that on the basis of the guideline.

Monte Carlo simulation of beta and -rays emitted by radon progeny products in a thundercloud electric field and an analytical research on the atmospheric diffusion of the radon gases in the East Asia area

Torii, Tatsuo; Sugita, Takeshi*; Kido, Hiroko*; Kanno, Mitsuhiro*; Kurosawa, Naohiro*

Taiki Denki Kenkyu, (69), p.32 - 33, 2006/00

http://ci.nii.ac.jp/naid/10018654450

no abstracts in English

Estimates of parameter and scenario uncertainties in shallow-land disposal of uranium wastes using deterministic and probabilistic safety assessment models

Takeda, Seiji; Kanno, Mitsuhiro; Minase, Naofumi; Kimura, Hideo

Journal of Nuclear Science and Technology, 39(8), p.929 - 937, 2002/08

https://doi.org/10.1080/18811248.2002.9715278

no abstracts in English

Development and application of a compartment model for environmental fate of radioactive materials released from nuclear accidents

Kurikami, Hiroshi; Niizato, Tadafumi; Tsuruta, Tadahiko; Kato, Tomoko; Kitamura, Akihiro; Kanno, Mitsuhiro*; Kurosawa, Naohiro*

no journal, , 

To understand environmental fate of radioactive materials released from nuclear accidents is important for recovery measures. We have developed a compartment model including all important compartments and processes to describe environmental fate of radioactive materials and have applied to the Fukushima environment. The results showed a good agreement with field investigations.

Analytical research on the atmospheric dispersion of the radon gases in East Asia area

Torii, Tatsuo; Kido, Hiroko*; Kanno, Mitsuhiro*; Kurosawa, Naohiro*

no journal, , 

A long-range model for advective diffusion of radon and its progeny products transported from the Asian continent was developed to investigate the effect of atmospheric radioactive substances to the winter thunderstorm. This system is based on regional meteorological model RAMS4.4 and material transport model HYPACT1.2. Using this system, a simulation was performed from October, 2002 to September, 2003. The annual fluctuation and advection from the continent were also studied.