The Influence of specimen surface roughness and temperature of steam injection on breakaway oxidation behavior of Zry-4 fuel cladding in steam at 1273 K

水蒸気中1273KにおけるZry-4被覆管のブレイクアウェイ酸化挙動に及ぼす試験片表面粗さ及び水蒸気注入温度の影響

Negyesi, M.; 天谷 政樹  

Negyesi, M.; Amaya, Masaki

Oxidation tests of Zry-4 fuel cladding in steam at 1273 K were carried out in this study. The effect of specimen surface roughness on the oxidation behavior was investigated. Steam was applied either at room temperature or at experimental temperature. Weight gain kinetics was evaluated by post-test weight measurement. Metallographic analysis was conducted using optical microscopy. Hydrogen pick-up was measured by gas extraction technique. The effect of specimen surface roughness on the oxidation kinetics as well as on the hydrogen absorption has not clearly been evidenced. The breakaway oxidation was suppressed significantly when the steam was applied at RT. The oxide breakaway was related to grain size of the base metal. Higher hydrogen absorption before the kinetic transition in the condition when steam was applied at 1273 K suggested enhanced oxide porosity.