Internship: Sintering of UO2 under varying atmospheres

Context

Since its very start in 1952, SCK CEN has studied scientific and technical issues of the nuclear fuel cycle. During this history of nuclear fuel research, SCK CEN has investigated innovative concepts for future developments, assisted the nuclear industry in their challenges to improve reliability, efficiency and safety of nuclear fuel and performed fundamental studies in close cooperation with the academic world.  Today, the nuclear fuel research resides under the group “Fuel Materials’ (FMA) of the Nuclear Engineering Technology institute (NET). A team of researchers and project leaders perform studies on the nuclear fuel cycle, covering manufacturing, in-reactor performance and stability of the spent nuclear fuel.  

Uranium dioxide pellets are the most widely used nuclear fuel and the general fabrication process is well-understood since decades. Yet, process parameters continue to be optimized. In the nuclear fuel laboratories various aspects of the UO2 sintering process are studied.

Project description

The internship combines sintering experiments conducted on uranium dioxide compacts and optimization of a data acquisition system. Both the data acquisition and sintering experiments will focus on gas atmosphere (gas flow, oxygen potential, humidity) and the densification process (temperature, displacement).

• The experimental part will consist of dilatometry experiments of UO2 pellets under different gas atmospheres. For these experiments, a gas mixing and monitoring system and a dilatometer will be used. The gas mixing and monitoring system mixes gas flows and monitors inlet and outlet oxygen potential and humidity. The dilatometer captures displacement and temperature.
• Integration of the existing data acquisition systems of the instruments cited above is expected to increase robustness and to limit errors in the data processing. It demands a good understanding of the different logging systems, proposing an approach to capture their output and writing a data acquisition script with a user interface.

An extension of the project could consist of integrating other instruments to the data acquisition system. A second extension could consist of thermodynamic modelling of gas/solid interactions of the same system.

Practical

The internship will be conducted in the period between 15th of January and 15th of July 2026, and is expected to have a duration of 20 to 24 weeks, including the on-site training period which takes around four weeks during which period the access to the nuclear laboratories is limited and is followed by a period with supervised access only.