[en] An overview of steady state tokamak (SST) studies on TRIAM-1M (R₀ =0.8 m, axb=0.12 mx0.18 m and B =8T) is presented. Current ramp-up scenario without using centre solenoid coils is reinvestigated with respect to controllability of the current ramp-up rate at the medium density region of 1-2x10¹⁹ m^-3. The plasma is initiated by ECH (fundamental o-mode at 170GHz with 200 kW) at B=6.7 T and the ramp-up rate below the technical limit of 150 kA/s for ITER can be achieved by choosing LH power. The physics understanding for the enhanced current drive (ECD) mode around the threshold power level is progressed from a viewpoint of the transition probability. A transition frequency f_trans for the ECD transition is determined as a function of P_CD. At ∼70 kW no transition occurs for f_trans of ∼ 0.017Hz meaning almost zero transition probability. With increasing P_C)D > P_th f_trans increases up to 10 Hz and the transition tends to occur with high probability. The record value of the discharge duration is updated to 3h 10 min in low N-bar_e ∼ 1x10¹⁸ m^-3 and low power (< 10 kW) discharge. The global particle balance in long duration discharges is investigated and the temporal change in wall pumping rate is determined. Although the density is low, at 30 min after the plasma initiation the gas supply was stopped to maintain the density constant. After that the density is sustained by the recycling flux alone until the end of the discharges. In addition to the recycling problem, in the high power and high density experiments, the localized PWI affects the SSO of the tokamak plasma. The effects of enhanced influx of metal impurities (Fe, Cr, Ni, Mo) on sustainment of the high performance ECD plasma are investigated. In order to evaluate the helium bombard-ing effects on the plasma facing component and hydrogen recycling in the future burning plasma, microscopic damage of metals exposed to long duration helium discharges was studied. The total exposure time is 128 sec. From thermal desorption experiments for the specimens the amount of retained helium was evaluated 3.9x10²⁰ He/m² and the scale length of ∼ 1mm in the SOL. (author)