Why would nuclear-reactor MHD systems need nonequilibrium ionization?

Nuclear-reactor MHD systems require nonequilibrium ionization because they typically operate at temperatures too low to achieve the thermal ionization necessary for effective power generation.1

In standard MHD generators, high temperatures—often exceeding 1,800 K—are required to produce the electrical conductivity needed for the plasma to interact efficiently with a magnetic field. Because conventional nuclear reactors using working fluids like hydrogen, argon, or helium operate below these thermal thresholds, they cannot rely on heat alone to ionize the gas. Consequently, nonequilibrium ionization—often involving the use of seeding materials—is employed to artificially increase the electrical conductivity of the working fluid, allowing the system to function despite the lower operating temperatures.21