Abstract

The paper considers the methods of the design analysis of the seismic resistance for the components of operating nuclear power plants in at three-dimensional setting using the finite element method. An algorithm to confirm the seismic resistance of equipment by a calculation method is proposed, and the limits of its application are determined. A mathematical model of the equipment is developed, and an example of the determination of natural frequencies and stresses for a three-dimensional structure is given. Two main types of calculation were used–static and dynamic. The seismic resistance of the equipment was estimated on the example of the K-1000-60/1500 steam turbine condenser and calculated at a seismic intensity of 6 points on the MSK-64 seismic intensity scale. In the course of solving this problem, results of the stress distribution in the housing and other structural elements of the condenser due to the action of combined normal operation and design-basis seismic loads were obtained. The seismic resistance of the equipment was calculated using the finite element method. Results of the assessment of the spatial complex stress state of the steam turbine condenser design due to the action of combined normal operation and design-basis seismic loads are obtained.

Keywords: Floor response spectrum; Seismic resistance; Finite element; Natural frequencies; Equivalent stresses

Abbreviations: NPP: Nuclear Power Plants; IAEA: International Atomic Energy Agency; FEM: Finite Element Method; FE: Finite Elements; NO: Normal Operation; DBS: Design-Basis Seismic; FRS: Floor Response Spectrum