Accelerator based Boron Neutron Capture Therapy (BNCT) system is considered to be more compact, safe, and useful than the nuclear power plant based BNCT. A new accelerator based BNCT project is started in Korea using 10 MeV proton beam linear accelerator. We designed the neutron generation target, and energy moderation assembly at the end of beam line. Beryllium foil is chosen as the neutron generation target. Since beryllium has serious problem of hydrogen blistering, however, good cooling mechanism should be adopted. In this report, we discuss on the neutron generation assembly of stable operating temperature and avoiding hydrogen blistering, as well as on the sufficient neutron energy moderation system to deliver epi-thermal neutron beam for patient treatments.