The Breeding Blanket (BB) is one of the key components of a fusion reactor. Its functions are (i)
tritium generation (“breeding”) by means of a nuclear reaction employing fusion neutrons and 6Li to
ensure the “tritium self-sufficiency” of the reactor, (ii) heat removal at high temperatures to allow for
efficient electricity production and for industrial processes, and (iii) contribution to radiation protection
of components behind the BB, such as the superconducting magnets. In the EU, four BB concepts
are being developed. The so-called Helium Cooled Pebble Bed (HCPB) BB is one of the candidate
BBs for the EU demonstration reactor (DEMO). This BB is based on the use of solid functional materials
(mixture of Li4SiO4 and Li2TiO3 as ceramic breeder material and Be12Ti as neutron multiplier)
and helium cooling of high pressure (8 MPa) and high temperatures (up to 500 °C) at low turbulent
Reynolds numbers. The latest conceptual design of the HCPB is based on single module segments,
with an actively cooled plasma facing U-shaped First Wall, followed by an arrangement of fuelbreeder
pin assemblies in the breeder zone, keeping a degree of analogy with fission reactors. Each
fuel-breeder pin is subjected to relatively high heat flux loads up to 0.2 MW/m² concentrated at the
front of the blanket. For maximize the reactor’s net efficiency, the fuel-pins designs need to focus on
heat transfer augmentation. Surface structuring is an appropriated method for heat transfer enhancement
by an increase convective and turbulent fluid mixing as a result of unsteady turbulent flow of
vortex shedding, shear layer separation and secondary flow motion.
The objective of the master thesis is a CFD (Ansys Workbench) analysis between different heat
transfer enhancement techniques for a fuel-breeder pin: rib-elements or dimples produced at the
inner walls of the pin and swirl tapes respectively should be investigated with respect to fabrication
aspects.
The work includes:
- Literature review.
- Geometry and numerical grid generation.
- CFD Case Studies.
- Writing the master thesis and presentation the results within a scientific colloquium.
Starting Date: immediately
Duration: 6 Month
Institute of Neutron Physics and Reactor Technology (INR)
Contact and Supervisor: Dr. -Ing. Francisco A. Hernández (francisco.hernandez@kit.edu) and Dr.-
Ing. Sebastian Ruck (sebastian.ruck@kit.edu)
Professorial supervisor: Professor. Dr.-Ing. Stieglitz
