Earthquake-proof structure for nuclear power plant

In the present invention, the floor of a control chamber, in which a computer for monitoring the operation state of a nuclear power plant and a central operation display board for displaying the results of the output are aparted from the floor of buildings. The floor of the control chamber described above is supported by a central control building by way of an earthquake-proof device and a damping device. The damping device comprises an actuator constituted so as to act as a dampling device upon occurrence of earthquakes exceeding a predetermined intensity. Further, it has a function of returning the floor of the control chamber to the original position by the restoring force of the springs after the earthquakes are over. Springs having a function of adjusting the proper frequency of the floor of the control chamber during earthquakes are disposed in the actuator. As a result, main parameters and the state of the operations of main equipments of the reactor can be monitored even during earthquakes. (I.S.)