Radiolysis of C5-BTBP in cyclohexanone irradiated in the absence and presence of an aqueous phase

Abstract

Spent nuclear fuel contains many highly radioactive species; hence solvents used in reprocessing will be subjected to radiolysis. In this study, solvents containing one of the BTBP molecules intended for the separation of trivalent actinides and lanthanides, the so called C5-BTBP, have been subjected to radiolysis and hydrolysis. We present here that this compound shows a dramatic decrease in both distribution ratios and separation factor when irradiated with higher doses up to 50 kGy; particularly in the presence of an aqueous phase. Furthermore, fast hydrolytic degradation is observed, which significantly contributes to the overall degree of decomposition. This is supported by speciation studies performed by HPLC and LC-MS methods. Proposed structures of the highest-yield degradation products are presented and they seem to confirm previously drawn structures for these products. From these studies it can be concluded that the presence of nitric acid or nitrate during irradiation leads to higher content of species containing keto groups.

Complexation and Extraction of Trivalent Actinides and Lanthanides by Triazinylpyridine N-Donor Ligands

“…158 Finally, the radiolytic and oxdiative stability of C5-BTBP in cyclohexanone in the presence of an aqueous phase was studied. 160 Stability versus oxidative degradation was tested by contacting solutions of C5-BTBP in cyclohexanone with water or with 0.01 mol/L HNO 3 + 0.99 mol/L NaNO 3 ; radiolytic stability was tested on (a) pure organic phases; (b) organic phases pre-equilibrated with 0.01 mol/L HNO 3 + 0.99 mol/L NaNO 3 ; and (c) organic phases in contact with 0.01 mol/L HNO 3 + 0.99 mol/L NaNO 3 . The results were evaluated by determining D Am(III) and D Eu(III) and by measuring C5-BTBP and degradation product concentrations using HPLC and LC-MS. After 330 h in contact with water, 2 mmol/L of initially 5 mmol/L C5-BTBP in cyclohexanone remained; the same decrease was observed after 200 h when in contact with 0.01 mol/L HNO 3 + 0.99 mol/L NaNO 3 .…”

“…Finally, the radiolytic and oxdiative stability of C5-BTBP in cyclohexanone in the presence of an aqueous phase was studied . Stability versus oxidative degradation was tested by contacting solutions of C5-BTBP in cyclohexanone with water or with 0.01 mol/L HNO 3 + 0.99 mol/L NaNO 3 ; radiolytic stability was tested on (a) pure organic phases; (b) organic phases pre-equilibrated with 0.01 mol/L HNO 3 + 0.99 mol/L NaNO 3 ; and (c) organic phases in contact with 0.01 mol/L HNO 3 + 0.99 mol/L NaNO 3 .…”

Stability of Different BTBP and BTPhen Extracting or Masking Compounds against γ Radiation

“…The radiation stability of different variations of the r-SANEX system has been widely studied in the last 2 decades. This research focused mainly on the molecules CyMe 4 -BTP, C5-BTBP, CyMe 4 -BTBP, and CyMe 4 -BTPhen in different types of diluents, such as octan-1-ol or its mixtures, FS-13, cyclohexanone, or its derivatives. ,− Each solvent behaved differently under irradiation. First, a difference was found in the distribution ratio ( D -values) when only the organic phase was irradiated and when the organic phase was irradiated in contact with the aqueous phase .…”

Gamma radiolytic stability of CyMe4BTBP and the effect of nitric acid

“…The presence of an aqueous phase during irradiation of C5-BTBP in cyclohexanone was studied by Fermvik et al [19]. It was found that in the presence of an aqueous phase the degradation of the extractant increased.…”