Development of wall conditioning and tritium removal techniques in TEXTOR for ITER and future fusion devices

Wall conditioning and tritium removal are discussed for ITER for standard glow discharge (GDC) which can operate only without toroidal magnetic field and for RF conditioning plasmas (ion cyclotron wall conditioning, ICWC) which can operate with the magnetic field on. ICWC plasmas have been produced in a wide range of parameters in TEXTOR using the conventional ICRF antennas and analyzed with respect to the wall cleaning efficiency. Various gases have been tested for wall conditioning and tritium removal such as hydrogen, helium, oxygen, nitrogen, ammonium and mixtures thereof. ICWC conditioning plasmas have been optimized based on proper gas mixtures and/or overlaying a small vertical magnetic field to the toroidal field. A simple 0-D plasma model has been developed which defines the parameter space needed for ICWC wall conditioning in ITER.