Concrete usage in Atomic Power Reactor Support

Abstract

Use of a concrete structure at an atomic power plant as a support for the reactor, as a biological radiation shield, and as a missile shield is described. Reasons are given for selecting conventional-aggregate concrete, instead of heavy'' concrete, around and under the reactor to retain radioactive emissions passing through the tank walls and surrounding water. A spherical shell selected to form the vapor container is carried on a ring of support columns resting on individual footings. The columns of the reactor support pierce this sphere surrounded by gas-tight bellows seals. This construction isolates the sphere from the effects of differential expansions and settlements of the reactor structure and permits use of a relatively thin, unlined steel shell. The design basis for the concrete support is given, including effects of creep and differential settlements. Also considered are possible serious consequences of applying standard allowable unit shear values to concrete members which may be in net tension over the entire cross section because of differential settlements. (auth)