PhD Position Interaction Chemistry Between Fission Products and Lead/Lead-Bismuth Eutectic Coolant

Research / Academic

Light water reactors (LWRs) are currently the reference in the nuclear industry, but do not provide a fully satisfying response to the social-political concerns. To replace these reactors at the end of their operating licenses, Generation IV reactors are currently being developed. Lead and Lead-Bismuth cooled Fast Reactors were selected as one of the most promising designs by the International Generation IV Forum. Liquid lead (Pb) and lead-bismuth eutectic (LBE) are particularly appealing as metallic coolants due to their high boiling points and chemical inertness with respect to air and water. In case of a clad breach, although extremely rare under normal operating conditions, the Pb/LBE coolant could come into contact with the irradiated nuclear fuel. (U,Pu)O2 is currently the reference for such type of reactor. From safety perspectives, it is essential to have a thorough knowledge of the potential products of interaction between the Pb/LBE coolant and the ceramic fuel. Depending on conditions of temperature and oxygen potential, new interaction phases can form with lower density and thermal conductivity than the fuel, which leads to fuel swelling and temperature increase, thus affecting the fuel behaviour. In addition, volatile and semi-volatile fission products such as cesium (Cs), iodine (I), molybdenum (Mo) and barium (Ba) are generated with a high fission yield during irradiation in the reactor, which are a primary concern for the public as they are the main cause for the radiological consequences of a severe accident. To assess the source term (the potential release of fission products to the environment in an accidental scenario), the interaction products between Pb/LBE and those fission products also need to be scrutinized.

The goal of this PhD will be to improve the understanding of the very poorly known chemistry of the interaction between lead and lead-bismuth eutectic coolant, fuel and key fission products, in particular the conditions required for the formation of ternary and quaternary phases, their thermal stability and thermodynamic properties,  which is essential for the safety assessment of the reactor during operation and accidental conditions.

To achieve this, the candidate will look at the structural and thermodynamic properties of the ternary  and quaternary phases in the (Pb-Bi)-(U-Cs-I-Mo-Ba)-O system. The work will involve solid state synthesis and characterization using X-ray diffraction, neutron diffraction, and X-ray absorption spectroscopy, the study of the compounds thermal expansion using high temperature X-ray diffraction, as well as calorimetric measurements of the thermodynamic properties, and measurements of the vapour pressures and retention capacity of Cs and  I fission products in Pb and LBE using Knudsen Effusion Mass Spectrometry. In addition, interaction tests between irradiated fast reactor fuel and Pb/LBE will be performed in the hot cells at the Joint Research Centre-Karlsruhe. The collected experimental data will serve as input to develop thermodynamic models of these systems using the CALPHAD method with the Thermocalc and Factsage softwares.

As part of the PhD project, the candidate will supervise bachelor and/or master students, and will contribute to some educational activities. 

This PhD position involves a close collaboration between the Department of Radiation Science and Technology (RST) of TU Delft and the Joint Research Centre of the European Commission in Karlsruhe (JRC Karlsruhe). Moreover, the close collaboration with the Reactor Institute Delft (RID) guarantees access to the HOR (Hoger Onderwijs reactor) research reactor and the irradiation facilities.


We are looking for an outstanding candidate with a master degree in Chemistry, Materials Science, Applied Science or a related field. Candidate should have an affinity for multidisciplinary fields of research and a hands-on attitude towards experimental work. Computer skills in simulation and modelling are also desirable. We expect creativity, flexibility and ability to co-operate within an interdisciplinary research group. Excellent communication skills, including good written and spoken English, as well as the ability to conduct independent scientific work are required. Delft University of Technology is a bilingual organisation; fluency in English is essential.

Salary Benefits:

TU Delft offers PhD-candidates a 4-year contract, with an official go/no go progress assessment after one year. Salary and benefits are in accordance with the Collective Labour Agreement for Dutch Universities, increasing from € 2395 per month in the first year to € 3061 in the fourth year. As a PhD candidate you will be enrolled in the TU Delft Graduate School. The TU Delft Graduate School provides an inspiring research environment with an excellent team of supervisors, academic staff and a mentor. The Doctoral Education Programme is aimed at developing your transferable, discipline-related and research skills.

The TU Delft offers a customisable compensation package, discounts on health insurance and sport memberships, and a monthly work costs contribution. Flexible work schedules can be arranged. For international applicants we offer the Coming to Delft Service and Partner Career Advice to assist you with your relocation.

Work Hours:

38 - 40 hours per week


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