Voltage Sensor

The Tokamak Physics Experiment (TPX) was a steady-state, tokamak to be built at the Princeton Plasma Physics Laboratory. It would have been the first tokamak in the world with an entirely superconducting magnet system. The project was terminated by the United States Congress in 1995. However, most of the TPX mission has been adopted recently by the South Korean project KSTAR (Korean Superconducting Tokamak Advanced Reactor) experiment at the Korean Basic Science Institue (KBSI). The principal obstacle to an all-superconducting tokamak magnet system has been the difficulty in detecting a quench and protecting the coil system in a high-noise, highvoltage environment. TPX adopted a a redundant, high noise-rejection design that will also be applicable to KSTAR. The purpose of this memorandum is to summarize the information that leads us to conclude that an internally cowound voltage sensor system alone should be adequate to protect the Tokamak Physics Experiment (TPX) magnets, in the event of a quench. Because of the importance of coil protection, the quench detection design philosophy for TPX is to require independent quench detection systems, any one of which should be adequate. This memorandum reviews the design requirements, the design, analysis that shows compliance with the requirements, and test data that supports the analysis models.