heptavalence

In the separation step of plutonium from uranium in Purex process, the existence of Tc(Ⅶ) decreases the separation efficiency of Pu from U by consumption of a great deal of reductants and brings difficulty into the following process because Tc(Ⅶ) flows into the uranium stream when U(Ⅳ) is used as reductant for tetravalent plutonium and N_2H_4 as supporting reductant to scavenge HNO_2.

二甲基羟胺在硝酸介质中的稳定性如何；单甲基肼与亚硝酸反应究竟能够快到什么程度；能否对硝酸介质中七价锝与二甲基羟胺、单甲基肼的反应给出结论性意见，锝的存在是否会造成还原剂的过度消耗等问题都还不清楚。