A 1MV AMS was installed in KIGAM (Korea Institute of Geoscience and Mineral Resources). After 4 months of installation, the AMS started normal operation from January 2008. This multi-element AMS was developed by HVEE to measure C-14, Be-10, and Al-26. The results of an acceptance test demonstrate that this machine is capable of routine C-14 age dating and of measurements of other radioisotopes in terms of accuracy and precision as well as the background level. After installation, an investigation aimed at determining the stable operating conditions was conducted, and background levels were determined to be as low as 10(-15) for C-14 and 10(-14) for Be-10 and Al-26.