Electromagnetics, Experiments, Fluid flow, Nuclear physics, Structural mechanics, Thermal engineering

how to handle 2 MW of power in a matchbox sized target.

Production of medical isotope Mo-99 is typically done in a nuclear reactor, but can be produced with high-energy electrons instead. This comes with many challenges, two of which are cooling the target and managing intense radiation. The first tests of such a system show that it can be realized successfully.

SMART project

cooling and managing radiation.

With the exposure module, Demcon is developing the heart of this groundbreaking factory. It comprises 1) the target where the electron beam hits the molybdenum target and the Mo-99 isotope is produced under the generation of extreme heat, and 2) the systems to extract the activated target and replenish it with fresh molybdenum (Mo-100).

Two key challenges in this project are cooling of the target and managing the intense radiation during exposure. The target is irradiated by a high-energy electron beam, resulting in extremely high power densities. We have to cool 2 megawatt of heat in a matchbox-sized target. Without cooling, the target would melt in 20 milliseconds. To ensure sufficient cooling, we use liquid sodium as the coolant. Liquid sodium, a metal with a melting point of around 100°C, has similar hydrodynamic properties as water. It has some disadvantages, such as its flammability and corrosivity, but has an extremely high thermal conductivity. Therefore, we extract heat very effectively from the target.

The intense radiation, on the other hand, causes all structural components to suffer from radiation damage. Materials swell and become brittle, causing components to deteriorate quickly. Challenges include selecting suitable materials, experimentally quantify unknowns and designing a modular system, in which parts can be maintained relatively easily.


“extreme heatloads require extreme cooling.”

The job is to design a cooling system for a target which is hit by a 2 megawatt electron beam. The target, the size of a match-box, should maintain its strength and structural integrity in all circumstances. Standard cooling solutions, such as gas-cooling of water-cooling do not work due to the extreme environment. The solution was to use a liquid metal (sodium), making use of its high thermal conductivity. We started with hand calculations, went on using simulations and concluded the study with an experimental validation of a scale model.

Demcon multiphysics.

Demcon multiphysics is an engineering agency with high-end expertise in the area of heat transfer, fluid dynamics, structural mechanics, acoustics, electromagnetism and nuclear physics. We support clients from a wide variety of market sectors and help them achieve their goals in research and development with deep physical insights.

We combine fundamental physical knowledge from an analytical approach with Computer Aided Engineering (CAE) simulations tools from ANSYS, MATHWORKS, COMSOL, STAR-CCM+ and FLUKA to setup, execute, analyze and evaluate numerical simulations. The use of Computational Fluid Dynamics (CFD), Finite Element Analysis (FEM / FEA), Lumped Element Modelling (LEM), Computational Electromagnetics (CEM) and Monte Carlo simulations enables us to make a virtual prototype of your design. With these techniques we can simulate the fluid and gas flows, energy exchange, heat and mass transfer, stresses, strains and vibrations in structures and the interaction of electromagnetic fields with other physical aspects like heat generation. Simulation-driven product development increases the development efficiency and reduces the product development time. Our services can therefore fully support you in the designing phase, from idea up to prototype, from prototype to final design.