The brand-new facility FRESH-UP (Fission product REmoval from Salts at High temperatures - Ultrafine Particles) is used to study the removal of solid fission products from molten salt reactors. The setup contains highly corrosive molten chloride salts at temperatures up to 700 degrees Celsius. An inert gas is introduced to facilitate fission product removal.
The experiments are part of the MIMOSA EURATOM project and are conducted by Ruben Dewes.
This setup has been developed and built together with DEMO (Electronic and Mechanical Development Department) of TU Delft.
The setup is used to study molten salt. It is well known that the combination of salt and metals is very challenging as it can quickly lead to corrosion. Therefore, this step in the development of molten salt reactors as a complement or alternative to traditional nuclear reactors is very important.
What is a Molten Salt Reactor?
A Molten Salt Reactor (MSR) is a nuclear reactor that uses liquid fuel-uranium or thorium dissolved in molten salt-instead of solid fuel rods. This design allows for higher efficiency, enhanced safety, and reduced nuclear waste compared to conventional reactors. MSRs operate at lower pressure, reducing the risk of explosions, and have a self-regulating reaction, making meltdowns unlikely. They can also use thorium, an abundant alternative to uranium, enabling a more sustainable fuel cycle. With continuous fuel recycling, MSRs produce significantly less long-lived radioactive waste than standard reactors.
What do we research on Molten Salt Reactors at the TU Delft?
TU Delft has been conducting research on MSRs for many years and has been involved in several large-scale European projects. Our university is one of the key players in Europe and collaborates intensively with universities, research institutes, and companies to advance MSR technology. Our expertise encompasses reactor physics, thermal-hydraulics, salt chemistry, corrosion studies, and reactor design and modeling.
What is FRESH-UP?
FRESH-UP (Fission REmoval of Solid fission products at High temperatures - Ultrafine Particles) is a unique facility that helps us understand the extraction of noble metals in real molten salts at temperatures up to 700 degrees Celsius. The facility is part of the European MIMOSA project and is the first of its kind. Designing and constructing FRESH-UP has been challenging because the salt is highly corrosive in the presence of water and oxygen. The materials used-including a transparent viewing window to observe the internal processes-must be able to withstand such harsh conditions.
What do we investigate with FRESH-UP?
Postdoctoral researcher Ruben Dewes and PhD candidate Nikita Mischenko, both members of Martin Rohde-s group at department of Radiation Science and Technology, are seeking solutions to clean the molten fuel salt. During reactor operation, gaseous and solid fission products form, and these must be removed to preserve fuel and material integrity. Our group has developed a method to extract solid fission products (so-called noble metals) by using helium bubbling in combination with a unique filtration system. The extraction efficiency will be studied as a function of gas flow rate, geometry, temperature, and noble metal characteristics.
What are the next steps?
The FRESH-UP facility has drawn international attention due to its unique design. It can be easily adapted for other research applications, such as two-phase flows in molten salts and material studies. After MIMOSA, the facility will be modified for studies on fission particle sedimentation on materials as part of the European ENDURANCE project.
