Nuclear power plants (NPP) haven’t often applied wireless equipment such as mobile terminals and wireless sensors compared with other industries, because wireless equipment need to consider about electromagnetic interference (EMI) to facilities and cyber security. Communication performance has a trade-off relation with security grade and EMI to high important facilities. Further it has become important to conform to security requirements regulated according to security level. We propose a new wireless system which communicates with authenticated equipment in required area where electromagnetic distribution is automatically controlled online, for the purpose of applying wireless equipment in NPP. Electromagnetic distribution is analyzed to communicate only in permitted area and avoid EMI to specified equipment. Each transmitter-receiver wireless modules (WMs) arranged according to the analysis distribution controls its own emission. As a result, electromagnetic distribution is maintained without changing for analysis distribution. In the maintained area, wireless equipment is authenticated and also falsification is detected for their transmission data. Our method based on message authentication code (MAC) reliably carries out authentication and falsification detection for each data packet of transmission data. Further, locations of wireless equipment are identified according to the triangular method applied WMs’ radiation. It is variable for cyber security to monitor each location of wireless equipment which store lager amounts of data. On the subject of cyber security, our wireless system not only carries out authentication and falsification detection at the time of communicating with wireless equipment, but also monitors each location of wireless equipment in required area. We intend to satisfy requirements from NEI and IAEA, further the guideline of NRC such as R.G.1.180 and R.G.5.71 regarding for nuclear facilities.