A high-power Nd:glass laser system (Sinmyung I) has been constructed and tested. In this system, we used a Nd:YLF laser as a master oscillator, a four-pass amplifier for preamplification, five stages of rod amplifiers, and image relaying units with spatial filters. The system has demonstrated in excess of 80 J (2 TW) with 40 ps (FWHM) pulse duration. Output energy, gain and spatial profile were measured at each amplification stage. With this laser system, a preliminary X-ray generation experiment was performed. Pinhole images, X-ray diode signals and X-ray spectrum were obtained for the irradiated target of copper, Detailed descriptions of the system performance and the X-ray generation experiment are presented.