Helium pumping and NBI fueling the burning plasma in low recycling tokamak regimes.*

The present high-recycling plasma regimes remain questionable for burning plasma due to inavoidable disruptions. The altenative is low recycling regimes relying on plasma pumping by lithium + fueling by NBI. Not sensitive to thermal conduction and PSI (replaced by collisionless flow of 15-20 keV electrons and ions to lithium), these regimes implement the best possible confinement (determined by particle diffusion) suitable for fusion amplification Q=5-10 even in the JET tokamak. Moreover at 50 % recycling, half of plasma energy is lost to the side walls (covered by Li) in disperse manner. The simplicity of Li-wall-fusion gives the hope on disruption avoidance and on removing the major regulation obstacle for burning DT plasmas. The technology of continuously flowing liquid lithium allows for the real-time recuperation of unburned tritium by absorbing it from plasma and delivering to outside facility as T solution in liquid Li. This invalidates the existing misconception on lithium incompatibility with DT plasma. This presentation, aiming to 150-200 MW DT neutron source (R/a=4/1 m, b/a=1.6, 1 m thick blanket), addresses helium exhaust pumping, and fueling by NBI. The sufficient sink for ionized helium seems to be realistic, while negative-ion NBI would allow to fuel the burning plasma at a proper plasma density and magnetic field. Even with H-plasma JET device is uniquely suitable for implementation of the best possible confinement and getting key data on He impurity pumping and on fueling with extra D NBI beam.