核燃料サイクル施設からの放射能放出に伴う環境ガンマ線線量率変動の定量化に関する研究(学位論文)

Study on the determination of the variation of environmental gamma-ray dose rate due to radioactivity discharged from nuclear fuel cycle facility (Thesis)

竹安 正則 

Takeyasu, Masanori

核燃料サイクル施設からの放射能放出に伴う環境ガンマ線線量率の変動の定量化を目的として、再処理施設運転に伴う環境ガンマ線線量率変動の準実時間定量化のための計算コード・システム(SIERRA-II)の開発、SIERRA-IIを用いた再処理施設運転に伴う環境ガンマ線線量率変動の定量化へ向けた検討、降雨により地表へ降下した雨水中Rn壊変生成物濃度の測定と大気中Rn壊変生成物降雨洗浄モデルの構築、降雨時にKrが放出されたときの環境ガンマ線線量率の変動の定量化を行ったものである。本研究により、開発したSIERRA-IIを用いて再処理施設運転時の環境ガンマ線線量率の変動を実用的な精度で定量化できることが明らかとなった。

The following studies were carried out with the purpose that the variation of environmental gamma-ray dose rate was determined due to radioactivity released from nuclear fuel cycle facility; Development of calculation code system (SIERRA-II) in order to determine in quasi-real time the variation of environmental gamma-ray dose rate due to the operation of reprocessing facility, examination for determining the variation of the dose rate during the operation using SIERRA-II, measurement of the concentration of Rn decay products in rainwater, and construction of the wet scavenging model for the atmospheric Rn decay products, determination of the variation of environmental gamma-ray dose rate due to the released Kr during rainfall. By these studies, it became clear that the developed SIERRA-II could determined the variation of environmental gamma-ray dose rate during the operation of reprocessing plant with practical accuracy.