Vibration-proof devices for reactor cores in nuclear reactors

Purpose: To damp the vibrations of reactor core structural elements in LMFBR type reactors upon occurrence of earthquakes. Constitution: Entrance nozzle portions of reactor core structural elements such as fuel assemblies and control rod assemblies are inserted and disposed into positioning insertion holes regularly disposed to a reactor core support plate. The periphery of the reactor core structural elements is surrounded with a reactor core barrel. Further, dampers are disposed at the contact surfaces in the upper portion pads, between the reactor core structural elements and between the reactor core structural elements and the inner portion of the reactor core barrel for damping the impact loads resulted therebetween. Accordingly, if the reactor core structural elements vibrate horizontally to collide the upper portion pads by way of the dampers upon occurrence of earthquakes, the impact loads are decayed and absorbed by the dampers to significantly decay the colliding force. (Moriyama, K.)