Feasibility study of technology for Pu solution monitoring including FP; Composition research of high active liquid waste and radiation measurement results on the surface of cell

先進プルトニウムモニタリング技術の適用性調査研究; 高レベル放射性廃液の組成調査及びセル外壁における放射線測定結果

松木 拓也 ; 舛井 健司 ; 関根 恵 ; 谷川 聖史 ; 安田 猛; 蔦木 浩一 ; 石山 港一 ; 西田 直樹 ; 堀籠 和志 ; 向 泰宣 ; 富川 裕文; 中村 仁宣 

Matsuki, Takuya; Masui, Kenji; Sekine, Megumi; Tanigawa, Masafumi; Yasuda, Takeshi; Tsutagi, Koichi; Ishiyama, Koichi; Nishida, Naoki; Horigome, Kazushi; Mukai, Yasunobu; Tomikawa, Hirofumi; Nakamura, Hironobu

東海再処理施設(TRP)では、高放射性廃液貯槽(HAW貯槽)で貯蔵している核分裂生成物(FP)を含んだ高放射性廃液(HALW)中に含まれるプルトニウム(Pu)量の監視を目的に新たな検出器の開発を2015年から2017年までの計画で進めている。これにより、HALW中のPu量をリアルタイムに監視することが可能となるため、国際原子力機関が長期課題として掲げている「より効果的・効率的な再処理施設の保障措置」に貢献することが可能となる。本計画の第1段階では、HALWから放出される放射線(中性子/線)の強度及びエネルギーの調査として、HALWの線スペクトル分析及びHAW貯槽が設置されているセル外壁での放射線測定を実施した。本論文では、検出器への適用の可能性のあるPu及びPu由来の線ピークの詳細及びセル外壁での放射線測定結果について報告する。

The International Atomic Energy Agency (IAEA) has proposed in its long-term research and development (R&D) plan, development of a real-time measurement technology to monitor and verify nuclear material movement continuously as part of an advanced approach to effectively and efficiently conduct safeguards for reprocessing facilities. Since the Tokai Reprocessing Plant (TRP) has solutions containing both Pu and fission products (FP), a new detector development project to monitor Pu with FP is being carried out from 2015 to 2017. This project is mainly conducted in the High Active Liquid Waste Storage (HALWS) in the TRP. For the first step of this project, as the confirmation of composition of high active liquid waste (HALW) to evaluate neutron/-ray emitted from solution in the selected HALW tank which has the most amount of Pu in HALW tanks at the TRP, we took HALW sample and conducted -ray spectrum measurement for HALW. As a study of detector setting location, to survey the available neutron/-ray (i.e. intensity) at the outside surface of the cell where HALW tank is located, we implemented continuous measurement by neutron/-ray detector. In this paper, we report three -ray peaks related with Pu and Pu measured in the composition research of HALW, which is needed to identify Pu amount by the new detector that we are developing and the result of radiation measurement on the surface of the cell.