Ever since the first nuclear power plant was built in Korea in 1977, the electricity produced by nuclear power plants has increased rapidly. It has been required that the spent nuclear fuel from nuclear power plants be managed safely. Therefore, technology for this purpose must also be developed. The Korea Atomic Energy Research Institute has developed the devices to manage these spent nuclear fuels. Due to high radiation levels, all these devices must be operated in a hot cell, which is a heavily shielded sealed room. Since these devices must be highly reliable, real-time monitoring is necessary to check that they are working correctly. A real-time three-dimensional graphic simulator is proposed to monitor the spent nuclear fuel dismantlement devices through the Internet. In order to reduce the visualization time of the devices, the abstraction of graphics data is performed. Also, simple operational information from a large number of sensors is extracted, and an efficient message format and its communication scheme are defined to reduce the communication time over the Internet.