PhD OFFER Radionuclide complexation with TBP/DBP

Who we are?

Amphos 21 is a scientific and strategic environmental consultancy.
R&D has been at the heart of Amphos 21 since its creation in 1994 and currently
accounts for around a third of our activities. It includes fundamental research,
encompassing experimental and modelling approaches, the development of PhD theses
in partnership with universities, and the application of our findings to client-focused
solutions. Besides technical and scientific reports, the team publishes extensively in
highly regarded international scientific journals.

What do we need?

We are looking for a highly motivated student interested in developing an experimental
PhD thesis in the field of radionuclide thermodynamics. The aim of the PhD is to
execute an experimental programme followed by extensive interpretation dealing with
the behaviour and complexation of tributyl phosphate (TBP) and dibutyl phosphate
(DBP) with different radionuclides under hyperalkaline conditions.

The background

As the urgency to combat the climate crisis grows, and considering recent geopolitical
events, nuclear energy has been identified as a key low carbon technology for meeting
growing global energy needs. One critical hurdle for the nuclear industry is the issue of
waste. Geological disposal in an engineered repository is the best supported solution
for nuclear waste yet remains a particularly complex challenge. Understanding the
behaviour of radionuclides underpins the scientific basis for the effective isolation of
nuclear waste and is the focus of this PhD.
Tributylphosphate (TBP) is an organophosphate widely used in industry, in particular in
UREX and PUREX processes, standard aqueous nuclear reprocessing methods for the
recovery of uranium and plutonium from used nuclear fuel. As a consequence, TBP is
expected to be present among wastes to be disposed in the repositories.
Understanding the effect of TBP in radionuclide behaviour is then relevant in the
performance assessment of the repository. However, a series of literature surveys
between 2017 – 2021 identified that thermodynamic data for TBP complexation with
radionuclides were extremely scarce. The use of concrete and cementitious materials
for construction purposes, as backfill material or for the solidification of waste packages
affects geochemical boundary conditions in the repository and buffers the pH to
alkaline conditions. At those pH values TBP can degrade to dibutyl phosphate (DBP)
and from this to monobutyl phosphate (MBP). The extend of this degradation process
will be investigated in this PhD by a series of kinetic experiments with alkaline
In a second phase of the project the complexation capacity of TBP, DBP and MBP will
be studied. The solubility of certain radionuclides and other elements of interest will be
investigated as a function of the organic ligand concentration at a given pH.
The final goal is to generate data that can be integrated into the international
thermodynamic database ThermoChimie ( ThermoChimie
is a thermodynamic database developed by the consortium formed by Andra (French
National Radioactive Waste Management Agency), Nuclear Waste Services (formerly
Radioactive Waste Management Limited, UK) and Ondraf/Niras (National Agency for
Radioactive Waste Management, Belgium). The purpose of the database is to provide
an accurate, consistent and complete thermodynamic data set to be used in
geochemical modelling of radionuclide and non-radiological pollutant behaviour. This
can be in support of repository performance assessments, research activities (such as
modelling experiments), or decisions about waste conditioning, reprocessing, and

What do we offer?

We offer a fully-funded PhD scholarship in the field of radionuclide thermodynamics.
The project will be hosted at Amphos 21 in Barcelona, Spain, within the Radioactive
Waste Management department lead by Dr. David García who will supervise the
student work.
The PhD. includes almost two years spent in the Clemson Environmental
Radiochemistry Laboratories at Clemson University, USA under Professor Brian
Powell. There is further possibility of working at other cutting-edge international
laboratories as part of this project.
The student will receive training in working with a range of radionuclides, including
neptunium and plutonium, and laboratory instruments such as gas chromatography–
mass spectrometry (GC-MS), liquid scintillation counting (LSC), attenuated total
reflectance Fourier transform infrared (ATR-FTIR), high-performance liquid
chromatography (HPLC), time-resolved laser fluorescence spectroscopy (TRLFS), and
UV-vis spectroscopy.
The candidate will have the opportunity to present their work at international
conferences and in written scientific publications.


– You have an MSc in Chemistry (or related disciplines) and experience with analytical
– You are fluent in written and spoken English (Knowledge of Spanish is a plus but
not a requirement).
– The position requires a long-term stay (more than 1 year) in the United States; the
ability to commit to this travel is essential.

How to apply?

To apply for this opportunity, please send your resume to and cc Please indicate in
the subject of the email the position (PhD candidate – RN complexation with TBP/DBP)
that you are interested in.