To assess the durability of concrete structures at nuclear power plants in Japan, plant life management technical evaluation is performed in accordance with the guidelines of the Architectural Institute of Japan for the maintenance and management of structures in nuclear facilities. Concrete carbonation is one of the degradation factors covered in the guidelines, and sampling is performed to confirm the progression of carbonation and predict future progression. Electricity providers in Japan perform sampling at locations constituting environments (temperature, relative humidity, carbon dioxide concentration) where carbonation progresses relatively fast to confirm that carbonation has not reached the rebars and to predict progression. In this study, accelerated carbonation tests were performed at high temperature, which is believed to accelerate carbonation, considering the parameters of relative humidity. Progression of carbonation and its impact on rebar corrosion were examined. The results showed that progression of carbonation in high-temperature environments can be predicted with a margin of safety using the Architectural Institute of Japan’s durability prediction equation. Moreover, because the humidity environments where carbonation progresses and the temperature environments where rebar corrosion progresses do not correspond with each other, rebars are typically unlikely to corrode even if carbonation has reached the rebars, provided they are not subjected to extreme wet-dry cycles.

为了评估日本核电厂中混凝土结构的耐久性，根据日本建筑学会对核设施中结构的维护和管理的准则，进行了电厂寿命管理技术评估。混凝土碳酸化是指南中涵盖的降解因素之一，并且进行采样以确认碳酸化的进程并预测未来的进程。日本的电力供应商会在构成环境（温度，相对湿度，二氧化碳浓度）的位置进行采样，这些位置碳酸化进程相对较快，以确认碳酸化尚未达到钢筋并预测进度。在这项研究中，加速碳化试验是在高温下进行的，考虑到相对湿度的参数，这被认为可以加速碳化。检查了碳化的进展及其对钢筋腐蚀的影响。结果表明，使用日本建筑学会的耐用性预测方程式可以安全地预测高温环境下的碳化进程。而且，由于碳化进行的湿度环境和钢筋腐蚀进行的温度环境彼此不对应，因此即使碳酸已经到达钢筋，只要它们不经受极端的湿-干循环，钢筋通常也不太可能腐蚀。结果表明，使用日本建筑学会的耐用性预测方程式可以安全地预测高温环境下的碳化进程。而且，由于碳化进行的湿度环境和钢筋腐蚀进行的温度环境彼此不对应，因此即使碳酸已经到达钢筋，只要它们不经受极端的湿-干循环，钢筋通常也不太可能腐蚀。结果表明，使用日本建筑学会的耐用性预测方程式可以安全地预测高温环境下的碳化进程。而且，由于碳化进行的湿度环境和钢筋腐蚀进行的温度环境彼此不对应，因此即使碳酸已经到达钢筋，只要它们不经受极端的湿-干循环，钢筋通常也不太可能腐蚀。