On a Solvent Extraction System for Recycling Used Nuclear Fuel with CyMe4-BTBP and TBP as Extracting Agents
Doctoral thesis, 2018

In Sweden, as well as in many other countries worldwide, the demand for electricity and electrical energy is high. One solution to satisfy this demand in the long term could be to upgrade the nuclear power plants, including recycling of used nuclear fuel, to Generation IV. The Generation IV concept, currently at the research stage, is based on a closed nuclear fuel cycle that includes both a reactor capable of fissioning considerably more nuclides than the thermal reactors of today and a used nuclear fuel recycling process. Recycling of the used nuclear fuel would increase the energy utilization of the fuel and make the final repository more sustainable. Different types of recycling processes are under development. One of these is the Grouped ActiNide EXtraction (GANEX) process. The Chalmers GANEX process is a solvent extraction process for extracting all of the actinides present simultaneously as a group by combining two extracting agents and a diluent into one single solvent.

The original Chalmers GANEX process used cyclohexanone as the diluent, which had some drawbacks such as low flashpoint and exothermic reactions with concentrated nitric acid. In this work the focus has therefore been on a new diluent, phenyl trifluoromethyl sulfone (FS-13). Current studies have shown that a solvent based on FS-13 has several promising features such as good actinide extraction while the fission product extraction remains low, fast kinetics, efficient back-extraction using two stripping steps and high stability against both hydrolysis and radiolysis. Thermodynamic investigations have revealed that the system reacts exothermically during the metal extraction. The system also offers a high solubility of CyMe4-BTBP, creating a possibility to optimise the organic phase according to the used fuel composition. The solvent was found to perform well under plutonium loading conditions, showing great promise for future use in recycling of Generation IV fuels.

Solvent Extraction

CyMe4-BTBP

FS-13

GANEX

TBP

KC-salen, Kemigården 4, Chalmers.
Opponent: Ken Nash, Washington State University, USA

Author

Jenny Halleröd

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Development of the Chalmers grouped actinide extraction process

Nukleonika,;Vol. 60(2015)p. 829-835

Journal article

Halleröd, J., Ekberg, C., Authen, T., Bertolo, L., Lin, M., Grüner, B., Svehla, J., Wagner, C., Geist, A., Panak, P., Aneheim, E.: On the basic extraction properties of a phenyl trifluoromethyl sulfone based GANEX system containing CyMe4-BTBP and TBP

Stability of phenyl trifluoromethyl sulfone as diluent in a grouped actinide extraction process

Journal of Radioanalytical and Nuclear Chemistry,;Vol. 304(2015)p. 287-291

Journal article

Halleröd, J., Ekberg, C., Authen, T., Aneheim, E.: Optimization of a GANEX system containing of CyMe4-BTBP and TBP in phenyl trifluoromethyl sulfone

Halleröd, J., Ekberg, C., Kajan, I., Aneheim, E.: Solubility thermodynamics of CyMe4-BTBP in various diluents mixed with TBP

Kärnkraften står idag för en stor del av både Sveriges och den industrialiserade världens elproduktion. Kärnkraftverken producerar dock stora mänger använt bränsle som både är radiotoxiskt och innehåller stora mängder outnyttjad energi. I Sverige planeras avfallshantering enligt en så kallad ”once through cycle” där bränslet används en gång i rektorn för att, efter 30 år i mellanlagring, placeras i ett djupt geologiskt slutförvar. Om bränslet istället återvinns kan det användas ett flertal gånger i rektorn innan det placeras i mellanlagret och slutligen i slutförvaret. Genom återvinning kan energiutvinningen ur bränslet ökas samtidigt som radiotoxiciteten i det slutgiltiga avfallet kan minskas. 

Flera olika processer för återvinning av använt kärnbränsle har under de senaste årtiondena utvecklats. En av dem är den så kallade Grouped ActiNide EXtraction (GANEX) processen, ett vätske-vätskeextraktionssystem som bygger på principen av två vätskor som inte vill blandas, precis som vatten och olja. Det använda bränslet löses upp i syra som tillsätts till en organisk fas bestående av extraktionsagenter, molekyler som binder och skapar komplex med vissa specifika metaller. På detta sätt kan de önskvärda metallerna med högt energiinnehåll separeras ut och återanvändas till produktion av nytt bränsle.

I den här avhandlingen har en Chalmers-utvecklad GANEX process undersökts, men fokus på en nyutvecklad organisk fas. Systemets specifika egenskaper har studerats med avseende på extraktionsegenskaper, koncentrationer av extraktionsagenter i systemet, kemisk stabilitet av den organiska fasen samt systemets beteende vid höga plutonium koncentrationer.

Subject Categories

Renewable Bioenergy Research

Chemical Process Engineering

Energy Systems

Areas of Advance

Energy

ISBN

978-91-7597-738-6

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4419

Publisher

Chalmers

KC-salen, Kemigården 4, Chalmers.

Opponent: Ken Nash, Washington State University, USA

More information

Latest update

5/14/2018