SEPARATION OF NP AND PU USING CATALYTIC ANION-EXCHANGERS BASED ON HETEROPOLYCOMPOUNDS

Catalytic anion exchangers (CA) containing several heteropolyanions (H PA) are synthesized. Two methods using them to separate Np and Pu are developed. In the static regime, CA are first treated with 10 column v olumes (c.v.) of 0.1 M N2H4. A model solution of 7.5 M HNO3 containing Np and Pu is prepared. The tetravalent actinides are stabilized and s orbed on CA (5% PV2Mo10O405-). Then, 20 c.v. of 0.1 M N2H5NO3 are pass ed through the CA layer at 68 degrees C with flow rate v = 0.19 ml/min . cm(2). Plutonium transfers to the reductive effluent. Neptunium is desorbed. The Np:PII ratio in the desorbate is determined. The Pu cont ent in the purified Np is less than 10(-4) mass %. In the dynamic regi me, a solution containing 7.5 M HNO3, 0.1 M N2H5NO3, 4 mg/ml Np(V), an d 0.1 mg/ml Pu(VI) is sorbed on CA previously treated with N2H4 soluti on (5% PV2MoO405-) at v = 0.19 ml/min . cm(2) and 68 degrees C. The CA layer is washed with 15 c. v. of a solution containing 7.5 M HNO3 and 0.15 M N2H5NO3 at v = 0.19 ml/min . cm(2) and 68 degrees C. Then, Np is desorbed. The effluent is evaporated. The Pu content in the purifie d Np is less than 10(-4) mass %.