Annual report 1991 on partitioning of actinide and fission product elements in high active liquid waste by truex process

not registered  ; Nomura, Kazunori  ; not registered; not registered; Kuno, Yusuke

Basic distribution studies and counter-current flowsheet experiments employing a mixture of CMPO with TBP as a reference solvent were conducted to evaluate the applicability of the TRUEX process to high level liquid wastes(HLLW) generated from the PUREX reprocessing process. Real highly active raffinate (HAR) solutions were used for these experiments. Concerning the major nuclide components of HLLW, various effecting factors on D values such as acidity, temperature, the ratios of CMPO/TBP and components concentration were investigated, respectively. Earlier (the first and second) counter-current flowsheet runs with laboratory scale mixer-settlers have shown excellent capability of the TRUEX process for actinides separation from real HAR solution. However, these tests showed unexpected significant retention of ruthenium and plutonium in the solvent. In the successive third run, some improvements to increase separation factor of these two nuclides and neptunium were demonstrated. This annual report summarizes results derived from the counter-current runs and basic study that treat the distribution of Np (IV, V, VI), other actinides and fission products, and the solubilities of extracted complexes to clarify the third phase split conditions. The results from supporting study which will cover solvent degradation and cleanup, and innovating new extractant, etc. are also included.