Our portable X-band (9.3GHz) 950 keV linac has been successfully upgraded. The problems of RF power oscillation, beam current oscillation and reduction and finally lack of X-ray intensity were solved by replacing the axial coupling cavities with the side-coupled ones. Designed X-ray dose rate of 0.05 Sv/min@1m is going to be achieved. X-ray source part with the local radiation shielding is connected by the flexible waveguide with the box of a 250 kW magnetron and a cooling unit. The total system consists of the three suit-case-size units, the last of which is one for the electric power supply. We have also developed a portable X-band (9.3GHz) 3.95MeV linac for on-site bridge inspection. The system consists of a 62kg X-ray source part without 80kg target collimator, a 62kg RF power source and other utility box of 116 kg. Designed X-ray dose rate is 2 Sv/min@1m with 200 pps repetition rate and we have achieved 0.5 Sv/min@1m with 50 pps repetition rate. Demonstration of measurement of wall thinning of metal pipes with thick thermal shielding and onsite inspection for nitric acid concentrating tower by 950 keV linac has been successfully achieved. Development of new X-ray detector for better sensitivity for hundreds keV through a few MeV and partial CT for reconstruction of degraded inner structure with the 3.95 MeV system are under way. BACKGROUND AND OBJECTIVE