Comparison of Traditional Iron-Dominated and Canted Cosine Theta Dipoles for PbLi Loop

A lead-lithium (PbLi) flow loop design is being carried out at Oak Ridge National Laboratory. PbLi is the most likely candidate for liquid tritium breeder material of fusion reactors, and a deuterium-tritium reaction is one of the leading candidates for fusion reactions. Although deuterium is found naturally, tritium is not. The project will develop a simulation workflow and design a flowing PbLi corrosion loop with a dipole magnetic field and surface heating in the test section, reaching prototypical fusion blanket conditions. The magnetic field requirements for the dipole are: maximum field of 4 Tesla, a good-field region (GFR) that is 200 mm by 200 mm and 1.5 m long, <1% non-uniformity and the ability to operate the magnet with the magnetic axis both horizontal and vertical. Two options are being considered: (1) a traditional iron-dominated dipole with rectangular coils and an iron yoke that includes pole tips, and (2) a canted cosine theta (CCT) dipole with an iron yoke. Although the CCT dipole is much more compact and requires a significantly smaller yoke for magnetic shielding, it does not allow easy access to the test section. This paper discusses the advantages and disadvantages of each design.