The invention relates to a constantly stable offshore
nuclear power platform. A permanent
ballast tank is arranged at the bottom of the
nuclear power platform; after the
nuclear power platform is in position, a
solid ballast poured into the permanent
ballast tank ensures that the center of gravity of the nuclear power platform is positioned below the center of
buoyancy; the upper part of the permanent
ballast tank is connected with the bottom of a
buoyancy tank through a truss and an inclined strut, the periphery at the upper part of the
buoyancy tank is connected with the bottom of a
deck through a plurality of upright posts, and the upright posts are used as a main support structure and a stability keeping structure of the nuclear power platform; a cylindrical nuclear island cabin is arranged between the middle of the top of the buoyancy tank and the
deck, the upper end of the nuclear island cabin penetrates through the
deck, and a nuclear island cabin hatch cover and an anti-collision protection structure are arranged on the deck; the nuclear island cabin contains a nuclear island
plant comprising a small
nuclear reactor containment and internal circuit facilities; after the nuclear power platform is in position, the height of the
sea level is larger than the immersion height of the
nuclear reactor containment. The constantly stable offshore nuclear power platform provided by the invention has the advantages of constant stability, good safety, simple structure and low construction cost, and can provide stable, reliable and
clean energy sources for offshore oil-gas
field development as well as island and
shore users.