Development of a New Flowsheet for Co-Separating the Transuranic Actinides: The “EURO-GANEX” Process

Abstract

A flowsheet for a novel GANEX (Grouped ActiNide EXtraction) process has been tested in a spiked flowsheet trial in a 32 stage plutonium-active centrifugal contactor rig with a simulant feed that contained 10 g/L plutonium as well as some fission products and other transuranic actinides. The solvent system used was a combination of 0.2 mol/L N,N,N',N'-tetraoctyl diglycolamide (TODGA) and 0.5 mol/L N,N'-(dimethyl-N,N'-dioctylhexylethoxymalonamide (DMDOHEMA) in a kerosene diluent that co-extracted actinides and lanthanides. Actinides were subsequently selectively co-stripped away from the lanthanides using a sulphonated and, therefore, hydrophilic bis-triazinyl pyridine (BTP) complexant in conjunction with acetohydroxamic acid (AHA). Plutonium and americium recoveries were high with decontamination factors across the strip contactors of ~14,000 and ~390 respectively. However, approximately 30 % of neptunium was lost to the aqueous raffinate which was due to recycling within the first extract-scrub section causing a large build-up of neptunium. Some accumulation of strontium was also observed but in this case it was fully directed to the raffinate stream. In the stripping section, a small fraction of europium (taken as a model lanthanide ion), ca. 7 %, was found in the actinide product stream. Modelling of selected data using the PAREX code has shown that, even with a relatively simplistic treatment, reasonable agreement between modelling and experiment can be obtained; giving confidence in the use of modelling to refine the GANEX flowsheet design prior to further testing with irradiated fast reactor fuel.

The effect of SO3-Ph-BTBP on stainless steel corrosion in nitric acid

“…All experiments are performed in 1.13 moldm -3 (5 wt%) HNO 3 . This concentration is slightly higher than that employed in the 2nd cycle TRU back-extraction in EURO-GANEX (0.8 moldm -3 ) [2], but representative of that found in the AHA extraction step in an advanced-PUREX process [7].…”

“…One of the aqueous fl ow sheets under review by the Safety of Actinide Separation Processes (SACSESS) consortium is the European Grouped Actinide Extraction (EURO-GANEX) process [1,2]. From head end to product fi nishing this fl ow sheet is broadly similar to the Plutonium Uranium Redox EXtraction (PUREX/advanced-PUREX) fl ow sheet [3][4][5][6][7], which is currently employed at the Thermal Oxide Reprocessing Plant (THORP) in the UK for the reprocessing of spent nuclear fuel.…”

Do An(iii) and Ln(iii) ions form heteroleptic complexes with diglycolamide and hydrophilic BT(B)P ligands in solvent extraction systems? A spectroscopic and DFT study

“…[14][15][16][17][18][19][20][21] The combination of co-extraction of An(III) and Ln(III) from the PUREX raffinate by using a lipophilic diglycolamide ligand TODGA (N,N,N 0 ,N 0 -tetra-n-octyl-diglycolamide, Scheme 2), followed by selective stripping of An(III) using a hydrophilic BTP, 2,6-bis(5,6di(3-sulphophenyl)-1,2,4-triazin-3-yl)pyridine, (SO 3 -Ph-BTP 4À , Scheme 1 top) dissolved in the aqueous phase, results in large separation factors of An(III) over Ln (III), which is the basis of various separation processes. [22][23][24][25][26] However, the experimental results related to the complexation of An(III) with these anionic N-donor ligands in the aqueous phase were rather difficult to interpret. Since Am(III) and Cm(III) prefer 9-fold coordination, 27,28 their coordination with three tridentate SO 3 -Ph-BTP 4À ligands was expected.…”

The effect of acetohydroxamic acid on stainless steel corrosion in nitric acid

“…This has led to the development of a variety of advanced fuel cycle concepts that incorporate AHA, such as URanium EXtraction Plus (UREX+) [7,8] and Grouped ActiNide Extraction (GANEX) [9,10], which do not extract pure plutonium but rather a mix of Pu, Am and Np, providing a non-proliferation advantage over the traditional PUREX process [11].…”