Studies on the Development of a Flow-Sheet for AHWR Spent Fuel Reprocessing Using TBP

Validation of Solvent Extraction Scheme for the Reprocessing of Advanced Heavy Water Reactor Spent Fuel UsingN,N-Dihexyl Octanamide as Extractant

“…Based on these observations, it was of interest to evaluate 0.36 M DHOA/ n -dodecane vis-à-vis 0.18 M TBP/ n -dodecane as solvents under the counter-current mode of operation. It is important to mention that in view of relatively more number of stages required for quantitative extraction of U and Pu, O/A was proposed to be maintained as 2 employing 0.18 M TBP/ n -dodecane as the solvent in the extraction cycle. , Batch studies also suggested that 4 M HNO 3 and 0.5 M HAN in 2 M HNO 3 can be used for the scrubbing of coextracted Th and for Pu partitioning, respectively. Loaded U was proposed to be efficiently stripped from the organic phase using 0.01 M HNO 3 .…”

“…Even though the proposed composition of AHWR feed solution is 2 g/L U + 2 g/L Pu + 100 g/L Th + 0.03 M HF + 0.1 M Al(NO 3 ) 3 at 3.5 M HNO 3 , respectively, − there was marginal variation in its distribution behavior of Pu at trace or 2 g/L concentrations. Therefore, tracer concentration of Pu (∼10 –5 M) was used in the simulated feed solution instead of proposed 2 g/L Pu. − Appropriate quantities of uranium, plutonium, and thorium from their stock solutions were mixed to get the final concentrations. Similarly, calculated quantities of Al(NO 3 ) 3 and of HF were also added to get their final concentrations as 0.1 M and 0.03 M, respectively.…”

“…In this context, completely incinerable high molecular weight N,N -dialkyl amides have drawn considerable attention of radiochemists as potential green extractants for actinides and have been proposed as alternatives to TBP for the reprocessing of irradiated fuels. − Our previous batch studies have shown that straight chain N,N -dihexyl octanamide (DHOA, Figure ) is a promising alternative extractant of TBP for the reprocessing of proposed AHWR spent fuel feed conditions. 0.36 M DHOA/ n -dodecane was found promising for selective extraction of U/Pu over Pa and Th as compared to that of 0.18 M TBP/ n -dodecane. − The coextracted thorium from the organic phase was proposed to be scrubbed using 4 M HNO 3 . A series of nonsalt forming reductants were evaluated suitable for the partitioning of plutonium.…”

“…This paper deals with the validation of the batch solvent extraction data by counter-current mixer settler runs under simulated AHWR spent fuel feed solution [2 g/L U + 2 g/L Pu + 100 g/L Th + 0.03 M HF + 0.1 M Al(NO 3 ) 3 at ∼4 M HNO 3 ] employing 0.36 M DHOA and 0.18 M TBP solutions in n-dodecane as solvents. , It should be noted that there was marginal variation (±5%) in the extraction of U and Pu ( at tracer or 2g/L ) under the simulated feed conditions. Therefore, the Pu tracer (∼10 –5 M) instead of 2 g/L was used in these studies.…”

Solvent extraction studies of protactinium for its recovery from short-cooled spent fuel and high-level waste solutions in thorium fuel cycle using diisobutyl carbinol (DIBC) as extractant

“…However, THOREX process employing 5% (v/v) tri-n-butyl phosphate (TBP) dissolved in aliphatic diluent has been evaluated in a greater detail form Indian perspective [11]. Recently, a modifi ed fl ow sheet has been proposed for the recovery of 233 U, Pu from AHWR spent fuel using 5% TBP/n-dodecane as the solvent [12]. However, Pa behavior under process conditions is not well understood.…”