In situ X-ray diffraction study of the oxide formed on alloy 600 in borated and lithiated high-temperature water

ホウ酸塩化及びリチウム化された高温水中の600合金上に形成された酸化物のその場X線回折

渡邉 真史*; 米澤 利夫*; 菖蒲 敬久  ; 城 鮎美; 庄子 哲雄*

Watanabe, Masashi*; Yonezawa, Toshio*; Shobu, Takahisa; Shiro, Ayumi; Shoji, Tetsuo*

In situ X-ray diffraction (XRD) measurements of the oxide film formed on Alloy 600 in borated and lithiated high-temperature water were conducted to demonstrate a capability to investigate rapid changes in oxide films during transient water chemistry conditions. In the presence of dissolved hydrogen (DH) = 30 cm/kg [HO] and dissolved oxygen (DO) 0.06 ppm, only spinel oxides were detected and no significant NiO peak was found even after 1,220 h exposure. By contrast, once the DO was increased to 8 ppm, a NiO peak grew rapidly. Within 7 h, the amount of NiO became comparable to that of spinel oxide. However, when DO was decreased again below 0.3 ppm and DH was increased up to 30 cm/kg [HO], the ratio of NiO to spinel did not change during 10 h. Thus, the rate of dissolution of NiO in DH = 30 cm/kg water seemed to be lower than the growth rate of NiO in high DO conditions.