Nuclear Science Research Institute Meteorological Statistics (2017-2021)

Futagawa, Kazuo; Kashimura, Keita; Sato, Daiki*; Kawasaki, Masatsugu

JAEA-Data/Code 2022-011, 75 Pages, 2023/03

JAEA-Data-Code-2022-011.pdf:1.49MB

These statistical results are based on the meteorological data observed at the Nuclear Science Research Institute in Japan Atomic Energy Agency and statistically processed according to "The guideline of meteorological statistics for the safety analysis of nuclear power reactor" (Nuclear Safety Commission on January 28, 1982; revised on March 29, 2001). The statistics are based on 5 years of meteorological data, from January 2017 to December 2021. These are statistical results of wind direction, wind speed, atmospheric stability, etc., which are used for dose assessment of the general public due to radioactive materials discharged into the atmosphere from nuclear reactor facilities.

Study on monitoring method of atmospheric radioactivity using continuous dust (gross beta) monitor in nuclear emergencies with atmospheric release

Kashimura, Keita; Kawasaki, Masatsugu; Okura, Takehisa

no journal, , 

In nuclear emergency response involving atmospheric release, the supplementary reference materials of the Nuclear Emergency Response Guideline require dust monitor to monitor radiation situation in the environment to be able to detect facility-induced releases of about 5 Bq/m for detecting unexpected releases earlier, and to determine the spatial distribution of radioactive materials in the air during emergencies, the difference in the gross beta activity concentration measured every 10 minutes is used. In this study, method of monitoring radioactive plume by dust monitor was investigated, and it was confirmed that the method can discriminate facility-induced releases of about 5 Bq/ m against variation of natural radionuclides. Furthermore, capability of the dust monitor corresponding to radioactive plume was confirmed. According to the time series comparison between the gross beta radioactivity concentration measured by the dust monitor and the radioactive concentration analyzed from gamma-ray emitted nuclides in the air following the Fukushima Daiichi Nuclear Power Plant accident (1F accident), a good correlation was observed and it was found that the dust monitor responded accurately to the fluctuation of the concentration in the radioactive plume. And it was confirmed that it was possible to discriminate the incremental difference in gross beta radioactivity caused by the facility of about 5 Bq/ m against the slight increase in concentration caused by the 1F accident.