EFFECT OF TECHNETIUM (Ⅶ) ON THE STRIPPING RATE OF PLUTONIUM(Ⅳ) BY URANIUM(Ⅳ) IN PUREX PROCESS

The influence of heptavalent technetium on the reducing stripping of tetravalent plutonium by tetravalent uranium is investigated.The single stage of stripping experiment is studied first. It is indicated that technetium has no obvious effect on the stripping rate of plutonium when its concentration is high enough to 441 mg/L in the organic phase.The stripping rate of plutonium decreases when the mixing time of two phases is long enough and the time of the stripping rate of plutonium decreased shortens when the concentration of technetium increases.The concentration ranges of the investigation, acid, plutonium, tetravalent uranium and hexavalent uranium have no great influence on the stripping rate of plutonium. The reflux extraction of the cascade experiment is done secondly.The results indicate that technetium has great effect on the stripping rate of plutonium when its concentration is more than 135 mg/L in 1BF. When it is less than 70 mg/L,technetium has no evident effect on the stripping rate of plutonium.The further research indicates that the reason for the decrease of the stripping rate of plutonium is that hydrazine is destroyed by the catalyzing low valent technetium. The decreasing of the concentration of heptavalent technetium and the shortening of the deposited time can minish the effect of technetium in PUREX process.