The potential for using the UNEX-extractant for the treatment of Idaho acidic HLW required substantiating all process characteristics, primarily all its hydrodynamic properties, as applied to extraction equipment on an industrial scale.

For this purpose, the main operations of the UNEX process work flow were checked by using Idaho simulated HLW on the EZR125 commercial

centrifugal contactor at the Research and Construction Institute of Assembling Technology (NIKIMT, Moscow). The operating conditions for the experiments corresponded to those of the previously performed tests for the improved work flow using real HLW. A basic diagram of the test rig for the UNEX process using a commercial centrifugal contactor is pre­sented in Fig. 9.8.

The tests of the UNEX process using industrial equipment provided the following evidence:

• the centrifugal contactor EZR125, working under UNEX process condi­tions, has a flowrate of 800 L/hour in total for all phases of the process (this corresponds to with the PUREX process system, with 30% TBP in kerosene and 2 M HNO3);

• entrainment of the aqueous phase into the organic was no more than 0.1%, while the aqueous phase did not practically contain any of the organic phase;

• adjusting the best interphase position in the contactor rotor for each of the specific process operations allows entrainment of the aqueous phase into the organic phase to be eliminated.