After the serious accident happened in March, 2011 at Fukushima Dai-ichi Nuclear Power Plant, various countermeasures are required and have been carried out. Regarding the radiation monitoring, the reinforced environmental resistance, additional monitoring equipment for the additional facilities and the diversity of monitoring principle with the existing monitoring devices are the scope of improvement. Hitachi, Ltd. and Hitachi-GE have been developing a fiber optic radiation monitor using a neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal and Eu3+ doped gadolinium tantalate (GdTaO4:Eu) crystal. Prototype monitors have been developed and their performance evaluation was carried out. As a result of the evaluation, fiber optic radiation monitors show very good characteristics for a nuclear power plant use. Therefore, we advanced a study about system constitution applying these detectors. In particular, system constitution plan and characteristics are listed in this paper in the case of CAMS, ARMS and monitoring post. Finally, the future prospects of the optic fiber radiation monitor are mentioned.