Reaction behavior of carbon dioxide with liquid sodium pool

炭酸ガスと液体ナトリウムプールとの反応挙動

宮原 信哉  ; 石川 浩康 ; 吉澤 善男*

Miyahara, Shinya; Ishikawa, Hiroyasu; Yoshizawa, Yoshio*

ナトリウム/炭酸ガス(CO)熱交換器における伝熱管破損事象を調べるため、COと液体ナトリウムプールとの反応挙動を実験的に研究した。実験は2種類実施し、1つは約15gの液体ナトリウムプールを流動するCOに晒しておもに反応が開始する熱化学条件と反応生成物の化学組成に関する情報を得た。実験では、ビデオカメラを用いて目視観察を行い、ナトリウムプールとその表面近傍の温度変化を熱電対で測定した。もう一つの実験では、熱交換器内のバウンダリー破損を模擬して約200gの液体ナトリウムプール中にCOを注入した。実験中のナトリウム温度とカバーガス温度は熱電対で測定した。これらの実験から、反応はある閾値温度を超えると起こることを明らかにし、温度上昇や圧力上昇、プール中の固体反応生成物の挙動等のナトリウム/ CO熱交換器における伝熱管破損事故の影響評価に有益で不可欠な情報を得た。

Reaction behavior of carbon dioxide (CO) with a liquid sodium pool was experimentally investigated to understand the consequences of boundary tube failure in a sodium-CO heat exchanger. In this study, two kinds of experiments were carried out to investigate the reaction behavior. In one experiment, about 1-5 g of liquid sodium pool were poured into flowing CO to obtain the information mainly about the thermo-chemical conditions to initiate the reaction and the chemical constituents of reaction products. During the experiment, visual observation was made using video-camera and the temperature change of the sodium pool and near the surface was measured by thermocouples. In the other experiment, CO was injected into about 200 g of liquid sodium pool to simulate the boundary failure in the sodium-CO heat exchanger. The temperature change of sodium pool and the cover gas was measured by thermocouples during the experiment. From these experiments, it became clear that the exothermic reaction occurred above a threshold temperature, and useful and indispensable information such as the resulting temperature and pressure rise and the behavior of solid reaction products in the pool was obtained to evaluate the consequences of boundary tube failure incident in a sodium-CO heat exchanger.