Conveners
THU-OR4-704 Stability and Quench
- arnaud badel (CNRS)
- Naoki HIRANO (National Institute for Fusion Science(NIFS))
We have been developing conduction-cooled HTS magnets wound with REBCO-coated conductors for MRI systems, with the aim of developing 9.4 T MRI magnets for whole-body and brain imaging. One of a key technology to implement the REBCO coil is quench protection and we proposed a quench protection method using electrically conductive epoxy resin [1]. The electrically conductive epoxy resin is...
In the last few years High Temperature Superconducting (HTS) non- and partially insulated coils have shown exceptional resilience towards quench and other disrupting effects in many practical experiments. These coils are therefore widely investigated as an approach towards larger high field HTS magnets for both Fusion and Particle Accelerator applications. One of the main concerns for these...
REBCO coated conductors (CCs) are expected to be applied to high field magnets due to their high longitudinal tensile strength and excellent critical current characteristics in high fields. For large scale magnets with large stored energy, the coil design is determined by the feasibility of quench protection. Although various quench protection methods have been proposed for REBCO magnets, the...
Growing interest for high-temperature superconducting (HTS) tapes, in particular the 2nd generation with functional layer of REBCO (RE = Y, Gd, Er,…), is motivated by an impressive progress in capability of such conductors to transport large currents. Nevertheless, this essential property, characterized by the value of critical current, Ic, quite often fluctuates along 100-1000 m lengths by...
High-temperature superconductors (HTS) are expected to have a major impact on the development of future particle accelerators and fusion energy systems. One of key challenges associated with HTS is a slow propagation of the normal zone that complicates early detection of thermal runaway (quench) in an HTS magnet using voltage-based techniques. Furthermore, fusion systems require field ramping...
A Mach-Zehnder Interferometer (MZI) based optical fiber sensing technique developed and patented by EPFL is an efficient and economical way to detect hotspots in HTS applications. Due to the MZI sensitivity being a composite of strain sensitive and temperature sensitive contributions, the MZI gives an instantaneous response to a quench (within 10 ms) resulting from the quick strain transfer to...
The critical heat flux in liquid hydrogen is ten times higher than that in liquid helium, and is approximately half of that in liquid nitrogen. Since the resistivity of pure metal such as copper or silver at 20 K is less than one-hundredth of that at 300 K, HTS magnets immersed in liquid hydrogen are expected to satisfy the cyostable condition at a practical current density for electric power...
