Mathematic modeling of seismic effects on WWER-1000 reactor

A mathematical model of the WWER-1000 reactor is described, used for the analysis of seismically induced horizontal oscillations of the reactor as a whole. The linear discretized dynamic model has 23 degrees of freedom and for its setting-up, the reactor was divided into 5 subsystems. Set up in FORTRAN, the software allows calculation of the eigenfrequencies and eigenvectors of the conservative model of the reactor, including the relative damping based on that of two selected eigenvectors (program MART). Programs SEIZA, SEIZ 1000 and STOCHA 1 enable the determination of the deformations of bonds between all the rigid bodies of the reactor and deformations of beam type continua in the points of discretization, and forces and bending stresses in the critical points of the upper reactor body. The input parameters of the programs MART and SEIZ 1000 are the design parameters of the reactor, which makes for a fast dynamic analysis if their values change. (Z.M.). 2 figs., 4 tabs., 7 refs