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坪田 陽一; 木村 泰久; 永井 佑哉; 小嶋 祥*; 床次 眞司*; 中川 貴博
Proceedings of International Conference on Decommissioning Challenges; Role and importance of innovations (DEM 2024) (Internet), 7 Pages, 2024/05
福島第一原子力発電所のPCV内で想定される過酷な環境(高湿度,高
/
線バックグラウンド)における
エアロゾルの「その場」モニタリングシステムを開発した。本システムの一部をMOX燃料施設のグローブボックス解体現場に設置し、その高速応答性能と長期運転能力を実証した。
荒井 陽一; 鈴木 誠矢; 岡村 信生; 渡部 雅之; 川野 昌平*; 川原田 義幸*; 松浦 由幸*; 山崎 誠志*
no journal, ,
Preventing re-criticality is an important safety issue in fuel debris removal operations. As one of the technologies to prevent re-criticality, we have been developing neutron absorbers. The water glass based neutron absorber is a type of solidified non-dissolvable neutron absorber, which is applied to the surface of fuel debris in water. The water glass based neutron absorber gradually increases in viscosity and hardens in close contact with the fuel debris surface. Since the fuel debris is water-cooled in the reactor and it is assumed to be porous, the water glass based neutron absorbent material coats the fuel debris while retaining water inside the fuel debris. In order to prevent hydrogen generation due to radiolysis of water, fuel debris is dried after removal operations. However, there is concern that water glass based neutron absorbent material adhering to the fuel debris may prevent the fuel debris from drying. Therefore, we started to investigate the effect of the water glass based neutron absorber coating on the drying behavior of fuel debris.
-contamination of reactor buildings by analyzing the stagnant water for decommissioning Fukushima Daiichi NPS二田 郁子; 比内 浩; 駒 義和
no journal, ,
Characterization of nuclear facility with severe accident is highly significant because contamination is extremely different from normal operation shutdown. However, in some cases, sampling which is necessary for characterization is often limited owing to difficulty to access the facility. We should combine fragmentary and little information and estimate the contamination. For Fukushima Daiichi NPS, cooling water has contacted with the damaged fuel and highly contaminated water has been generated and accumulated in basement floor of the reactors. Constructional materials of concretes and metals have been contaminated by the water. We elucidated estimated mechanism of -emitting nuclides contamination by means of analysis of stagnant water samples.