Study on ageing behavior of reprocessing plants, 1; Long term corrosion of stainless steel in boiling nitric acid at heating portion

Ueno, Fumiyoshi  ; Kato, Chiaki   ; Motooka, Takafumi; Yamamoto, Masahiro ; Uchiyama, Gunzo ; Nojima, Yasuo*; Fujine, Sachio*

Long term corrosion of stainless steel in boiling nitric acid solution at heating portion of dissolver and concentrator was studied to investigate ageing behavior of the components in spent fuel reprocessing plant. Corrosion tests carried out more than 8,000 hours in test duration using simulated test solutions including non-radioactive V and Ru ions. As the result, several simulated corrosion data which were equivalent and accelerated about three times of corrosion rate in comparison with actual components were obtained. And it was considered that loss of thickness caused by intergranular corrosion increases as approximately constant rate in stainless steel components but acceleration of corrosion could be observed in the case of remarkable loss of thickness.