Low Thermal Conductivity Support Links for High-Radiation Environments

Period of Performance: 06/12/2017 - 03/11/2018

$150K

Phase 1 SBIR

Recipient Firm

Ultramet
12173 Montague Street Array
Pacoima, CA 91331
Firm POC
Principal Investigator

Abstract

Superconducting magnets used for plasma confinement in magnetic fusion energy systems operate at cryogenic temperatures. The support structures used to hold them in place act as a heat leak path from room temperature areas to the superconductors. This results in the need for additional cryogenic refrigeration capacity, which is expensive. High-strength, low thermal conductivity, radiation-tolerant materials are needed, particularly below the toroidal magnets where the gravity loads are greatest. Open-cell metallic foams can be made from high-strength, damage-tolerant, and radiation-tolerant materials such as tantalum or niobium. The high porosity of the foam (typically >80 vol%), combined with the tortuous path of the foam structure, results in very low thermal conductivity. Samples of structural open-cell foam will be made from various materials with various relative densities. The thermal conductivities and mechanical properties of the materials will be measured. Using those data, a low-conductivity support structure for the thermal isolation system will be fabricated. All cryogenic systems (not just those used in magnetic fusion confinement) are ultimately connected to a support that is at ambient temperature, and the structures along the connection path represent a heat leak path. By developing a structural insulator that is suitable for use with these systems, the material can be used in many different applications ranging from magnetic fusion confinement to particle accelerators for high-energy physics to superconducting power distribution systems to medical imaging machines.