NUCLEAR REACTOR VESSEL

PURPOSE:To prevent possible buckling with the application of a shearing force on a vessel shell, by providing a skew rib on a cylinder of a fast breeder tank type nuclear reactor vessel to enhance rigidity of the vessel. CONSTITUTION:One circle of a skew V-shaped rid 17 is arranged on the circumference of a shell section of a fast breeder tank type nuclear reactor vessel 1 to reinforce the container 1 aslant. When an earth quake occurs to apply a horizontal seismic load, the nuclear reactor vessel 1 vibrates at the lower part thereof with the upper part thereof 1 fixed as the nuclear reactor vessel 1 is supported with a support of a roof slab 3. In such a case, a possible shear buckling can be prevented with the skew rib 17 arranged against a force generated aslant to the shell of the vessel 1.