Dismantling technology for large-scale sodium components used for a long time, 2; Adhesion behavior of sodium vapor in cover gas region

Suzuki, Shigeaki*; Hayakawa, Masato; Shimoyama, Kazuhito ; Umeda, Ryota ; Yoshida, Eiichi; Miyakoshi, Hiroyuki

We are conducting dismantling inspection of large-scale sodium component that we have been using in sodium environment for a long time. We got the cover gas area sodium deposition rate of the large tank used for several decades. As a result of examination based on the data and past findings, it was possible to derive the recommended value "1.0e-10 g/cm/s" for the cover gas region sodium adhesion rate of the plant operating in the low temperature range (150 to 200C). For disassembling large sodium equipment, it is possible to estimate and evaluate sodium adhesion amount based on this recommended value and operation history. With this evaluation, it became possible to increase the reliability of disassembly technology for safety measures and safety management related to sodium fires etc.