TOWARDS A DIAMEX PROCESS FLOWSHEET USING HIGH ACTIVE CONCENTRATE (HAC)
The efficiency of MA recovery in the DIAMEX process has already been demonstrated using HAR. The next step aims at the demonstration of reprocessing from HAC as feed, in view of an industrial application. The volume reduction would reduce the size of the installation and thereby the costs of the process. The first step towards the demonstration of a DIAMEX process using HAC is the production of the genuine solutions. In ITU about 9 L HAR raffinate has been prepared, from PUREX reprocessing of 1.4 kg of MOX fuel, and characterised in order to produce HAC for the upcoming extraction tests. For this purpose, the HAR is subjected to a concentration/denitration process to obtain HAC with a final acidity compatible with the DIAMEX operating conditions, i.e. around 3 M HNO3. This process has been tested and optimised using HAR-simulate. Promising results were found for concentration factors (CF) of 6 to 8. At CF of 39 a significant co-precipitation of lanthanides occurred.
Partitioning of minor actinides from HLLW using the DIAMEX process.Part 1 - Demonstration of extraction performances and hydraulic behaviour of the solvent in a continuous process
The French DIAMEX process shows very promising capabilities in separating minor actinides from HLLW. A counter-current centrifugal extractor experiment has been conducted to investigate the capabilities and possibilities of the DIAMEX process (hydraulic and extraction behaviour), for the separation of lanthanides from a simulated High Level Liquid Waste (HLLW), corresponding in concentration to a raffinate from the PUREX process. A ´´hot´´ batch test, using genuine HLLW, and a continuous counter-current experiment have verified the excellent extraction and hydraulic behaviour, respectively. With only four extraction stages in the cold experiment, lanthanide decontamination factors were higher than 2000, except for europium. Co-extraction of molybdenum and zirconium was efficiently prevented using oxalic acid in the feed solution. The back-extraction was very efficient, yielding in 4 stages more than 99% recovery of lanthanides. Palladium and ruthenium were more difficult to back-extract and for these elements further investigations are needed.
Annual Report for 1972
Abstract : Contents: Electron scattering experiments; photo- and electro-disintegration experiments; research with low energy facility (pulse radiolysis); accelerator operation; accelerator modification; theoretical studies on the storage ring project; health physics - radiation exposure of personnel; residual activity; area monitoring.