模擬用過條件鋯二合金護套在水氣環境之高溫氧化動力學

Oxidation Kinetics Study on the Simulated Spent Fuel Cladding of Zircaloy-2 in High-temperature Vapor

10.6376/JCCE.201409_28(3).0006

陳仁宏(J. H. Chen)；陳彥辰(Y. C. Chen)；曾哲聰(C. C. Tseng)

用過燃料護套 ； 鋯二合金 ； 水氣環境 ； 氧化動力學 ； Spent fuel cladding ； Zircaloy-2 ； Vapor ； Oxidation kinetics

防蝕工程

28卷3期（2014 / 09 / 01）

155 - 165

繁體中文

本研究探討用過燃料護套鋯二合金在水氣環境下之高溫氧化行為。為模擬用過燃料護套內部氫化與表面具氧化層之條件，鋯二合金管材經過充氫及預氧化處理，獲得表面形成約30 μm厚氧化層，及內部有氫含量100 ppm ~ 1000 ppm範圍條件之模擬試片，以熱重分析儀(TGA)進行500 °C ~ 800 °C水氣條件之氧化實驗。結果顯示模擬條件試片呈現二階段線性氧化速率；初始階段為較低的線性速率，氧化層增加1 ~ 3 μm後轉變至第二階段較高的線性速率。試片氫含量對氧化速率常數之效應在初始階段並不明顯，但在轉變後階段則顯現影響氧化速率常數之效應。

The oxidation kinetics of Zircaloy-2 cladding in vapor was investigated to study the oxidation behavior of the spent fuel cladding. To simulate the conditions of spent fuel cladding, hydriding and pre-oxidation of the Zircaloy-2 tube specimens were conducted. The simulated specimens with oxide thickness of 30 μm on the cladding surface and hydrogen contents of 100 ppm ~ 1000 ppm in the cladding were obtained. Oxidation tests in vapor at the temperature ranges of 500 °C ~ 800 °C were carried out by TGA. The results showed that the simulated specimens revealed two-stage linear oxidation kinetics. At the initial stage, a lower linear rate law was exhibited until 1 ~ 3 μm oxide scale formed and then the transition of oxidation rate occurred. After transition, the oxidation kinetics followed a higher linear rate law. The effect of hydriding on the oxidation rate constant was insignificant for the initial stage oxidation, it was, however, more evident at the stage of post-transition.