A preliminary study of dihydroxyurea application in plutonium purification cycle

Abstract

The back extraction of Pu from 30% TBP/kerosene with dihydroxyurea (DHU) was studied in relation to the contact time, nitric acid concentration, phase ratio, etc. The back-extraction efficiency can reach 87% at phase ratio (o/a) ≤4: 1, contacting time ≥1 min, niitric acid concentration ≤0.4 M, and reductant concentration ≥0.4 M at 15°C and Pu concentration in the organic phase of 12 g l−1. The back-extraction efficiency decreases with an increase in the Pu(IV) concentration in the organic phase or in the Pu(III) concentration in the aqueous phase. The application of DHU in Pu cycle was studied in a 12-step countercurrent cascade experiment. The results show that DHU can satisfy the technical requirements at 15°C and phase ratio (2BF: 2BX: 2BS) = 4: 1: 1. The Pu recovery efficiency is 99.96%.