Large-scale buckling tests of steel containment vessel of 'Monju'

The nuclear reactor containment vessel of the proto-type fast breeder reactor plant ''Monju'' is the largest one of the self-standing, steel cylindrical type containment vessels in the world. This containment vessel should have an adequate buckling resistance against overturning moments, accompanied with transverse shearing loads due to horizontal earthquake stresses, and at the same time, against the axial compression due to dead weight loads and vertical earthquake stresses. To verify the adequate buckling strength of this containment vessel, large-scale buckling tests were carried out by using fabricated steel cylinder models. The results of the tests shows remarkable effects of ring-stiffener spacings on the buckling of ring-stiffened cylinders subjected to axial compression, bending and shear stresses. By these effects the buckling strength of ring-stiffened cylinders is apparently stronger than that of unstiffened cylinders, which were so far referred to as the buckling criteria of cylindrical shells. On the other hand, the amount of scatter in the measured buckling loads under the same conditions is very small in such large-scale fabricated cylinder models. On the basis of these test results, the committee for seismic resistance of ''Monju'' reactor containment vessel in the Power Reactor and Nuclear Fuel Development Corporation confirmed its adequate buckling resistance against earthquake stresses. (author)