Influence of dose rate on the radiolytic stability of a BTBP solvent for actinide(III)/lanthanide(III) separation

The recently developed ligand MF2-BTBP dissolved in cyclohexanone is a promising solvent for the group separation of trivalent actinides(Ill) from the lanthanides(Ill). Its high stability against nitric acid has been demonstrated recently. Since the solvent is also exposed to a continuously high radiation level in the counter current process, the radiolytic stability of the solvent was examined in this study. Irradiation experiments were carried out up to an absorbed dose of 100 kGy and the effect of the dose rate was investigated. The extraction behaviour for An(III)/Ln(III) separation was studied after radiolysis for evaluation. It was found that during high dose rate irradiation the extraction efficiency for both Am(III) and Eu(III) decreased significantly with increasing absorbed dose, whereas during the low dose rate irradiation the extraction efficiencies remained more or less at the same level

Influence of dose rate on the radiolytic stability of a BTBP solvent for actinide(III)/lanthanide(III) separation

The recently developed ligand MF2-BTBP dissolved in cyclohexanone is a promising solvent for the group separation of trivalent actinides(Ill) from the lanthanides(Ill). Its high stability against nitric acid has been demonstrated recently. Since the solvent is also exposed to a continuously high radiation level in the counter current process, the radiolytic stability of the solvent was examined in this study. Irradiation experiments were carried out up to an absorbed dose of 100 kGy and the effect of the dose rate was investigated. The extraction behaviour for An(III)/Ln(III) separation was studied after radiolysis for evaluation. It was found that during high dose rate irradiation the extraction efficiency for both Am(III) and Eu(III) decreased significantly with increasing absorbed dose, whereas during the low dose rate irradiation the extraction efficiencies remained more or less at the same level

Separation of Actinides(III) from Lanthanides(III) in Simulated Nuclear Waste Streams using 6,6'-Bis-(5,6dipentyl-[1,2,4]triazin-3yl)-[2,2']bipyridinyl (C5-BTBP) in Cyclohexanone

An extraction system comprising 6,6'-bis-(5,6-dipentyl-[1,2,4] triazin-3-yl)[ 2,2'] bipyridinyl (C5-BTBP) dissolved in cyclohexanone was investigated. The main purpose of this investigation was to extract and separate actinides(III) from lanthanides(III), both of which are present in the waste from the reprocessing of spent nuclear fuel. The system studied showed high distribution ratios for the actinides( III) and a high separation factor between actinides and lanthanides (SFAm/Eu around 150). The extraction kinetics were fast with equilibrium being reached in 5 minutes. The effects of temperature on the extraction and the stoichiometry of the extracted complex were investigated. The extraction of californium( III) was studied and it was found that the BTBP molecule has a higher affinity for californium than for americium (SFCf/Am around 4). This system could be used to separate actinides( III) from lanthanide fission products with high efficiency, if used in conjunction with a pre-equilibrium step

The behaviour of organic solvents containing C5-BTBP and CyMe4-BTBP at low irradiation doses

Low doses of gamma radiation were given to four different solvents containing C5-BTBP and CyMe4-BTBP, each molecule dissolved both in cyclohexanone and hexanol. Four corresponding solvents were kept unirradiated and used as references for the extraction experiments. Multiple samples were taken from both the irradiated solutions and the reference solutions at certain time intervals. The samples were used in extraction experiments with the radionuclides Am-241 and Eu-152. The protection against radiolysis of the extracting molecules by the diluent used for dissolution without adding a scavenger molecule was checked. The interplay between the diluent and the side group of the extracting molecule for protection against radiolysis was also studied by keeping the same type of core molecule for binding to the metal ions and varying the diluent and side group. The results were unexpected. The presence of a cyclic molecule as both a side group or diluent seems to keep the extraction of europium almost unaffected by radiolysis, while americium behaves differently from solvent to solvent. The diluent alone does not protect the extracting molecule. In some of the studied systems there is a distinct change in the extraction behaviour of Am between the irradiated and reference solutions, an effect that is however only present at the beginning of the experimental series. At later times the difference in distribution ratios between the irradiated and reference solution is constant. This phenomenon is found only when the side group and diluent are structurally dissimilar