Identification of minor products obtained during radiolysis of tributylphosphate (TBP)

The structure identification of the fraction of minor products obtained during radiolysis of tributylphosphate (TBP), the solvent used in reprocessing of nuclear fuel, is reported. These results were realised from the distillation residue of the EDIT loop. The primary radiolysis formed TBP radical dimerises and is transformed under oxidative nitric acid conditions into several butyl chains substituted hydroxy or nitro phosphates as well as alkylated TBP. The butyl chain hydroxylated phosphate is leading to ketones, ethers and O-ester derivatives. The structures were determined by tandem mass spectrometry (MS-MS) and isotopic labelling techniques as well as by ion filiation and isotopic exchange studies. The analytical method developed consisted of the use of the integrated GC-MS, or GC-MS-MS, isotopic labelling technique. The combination of these techniques enabled to identify and to semi-quantify most of highly functionalised TBP without their prior separation from the post radiolysis mixtures.