高速炉蒸気発生器伝熱管周囲に形成されるナトリウム-水反応環境を考慮したターゲットウェステージ評価

Evaluation of target-wastage in consideration of sodium-water reaction environment formed on the periphery of an adjacent tube in steam generator of sodium-cooled fast reactor

栗原 成計 ; 梅田 良太 ; 下山 一仁 ; 菊地 晋  ; 大島 宏之; 奈良林 直*

Kurihara, Akikazu; Umeda, Ryota; Shimoyama, Kazuhito; Kikuchi, Shin; Ohshima, Hiroyuki; Narabayashi, Tadashi*

ナトリウム(Na)冷却型高速炉の蒸気発生器(SG)で想定されるウェステージ現象について、主要生成物と同定した高温のNaOH/NaO環境における流れ加速型腐食(FAC)実験や実機SG伝熱管材料を含む種々の材料に水滴を衝突させた液滴衝突エロージョン(LDI)実験を実施し、それぞれの相関式を導出した。これらの相関式を融合し、FACとLDIを重畳させた新たなウェステージ相関式を提案するとともに、これまでに取得したターゲットウェステージデータを用いてその適用性を検討し、過去データと良い相関を示すことを確認した。

Wastage phenomena on adjacent tubes (target-wastage) arise from water/steam leak in steam generators of sodium-cooled fast reactors. Target-wastage is likely to be caused by liquid droplet impingement erosion (LDI) and flow-accelerated corrosion (FAC) in an environment marked by high-temperature and high-alkali (reaction jet) due to sodium-water reaction. The authors carried out flow-accelerated corrosion experiments as a part of phenomena clarification experiments for target-wastage by using tube material under high-temperature sodium-hydroxide and sodium monoxide conditions which are mainly generated by sodium-water reaction. New wastage correlations were derived from LDI and FAC data based on influencing factors which were formed on the periphery of an adjacent tube, and were confirmed those applicability to water leak event in this report.