Abstract:  Considering the construction, installation, commissioning, operation, refueling and emergency of nuclear power plant, a mobile platform is proposed. The same as a fixed platform, without the movement due to wave motion, the operators have a mild working and living condition. The nuclear island is located below the sea surface, so the safety is improved. By an artificial ground, the construction vessel is not necessary for installation and decommissioning. The platform provides a power-supply source for large oil field or oil field group.