硝酸プルトニウム溶液での各種金属材料の耐食性

抄録

Corrosion behavior of several metals exposed in plutonium nitrate solution was studied. Plutonium nitrate solution with the plutonium concentration ranging from 0.01 to 300g/l was used as a corrosive medium. Specimens tested were type 304 ULC (304 ULC) stainless steel, type 310Nb (310Nb) stainless steel, titanium (Ti), titanium-5% tantalum alloy (Ti-5Ta), and zirconium (Zr). Corrosion behavior of these metals in plutonium nitrate solution was evaluated through examining electrochemical characteristics and corrosion rates obtained by weight loss measurement. From the results of the corrosion tests, it was found that the corrosion rate of stainless steels i.e. 304 ULC and 310Nb, increases by the presence of plutonium in nitric acid solution. The corrosion potential of the stainless steels shifted linearly towards the noble direction as the concentration of plutonium increases. It is thought that the shifts in corrosion potential of the stainless steels to the noble direction results an increase in anodic current and, hence, corrosion rate. Valve metals, i.e. Ti, Ti-5Ta and Zr, showed good corrosionresistance over the whole range of plutonium concentration examined here.