Forced vibration tests and simulation analyses of reactor containment facilities (PWR-type)

The forced vibration tests were conducted on the containment facilities (Reactor Building) of Unit No. 2 of the Ikata Nuclear Power Station. All of the buildings of the facilities were completed and most of the machinery and piping system was set up when the tests were performed. The containment facilities consist of an outer shield wall (O/S), an inner concrete structure (I/C), and a steel containment vessel (C/V). The purpose of the tests was to investigate their vibrational behavior (natural frequency, natural mode and damping ratio). With the results of the tests we have confirmed the adequacy of the seismic designs of the O/S and I/C structures. This paper describes 1) the outline of the forced vibration tests; 2) the vibrational behavior obtained in the results of the tests; and 3) the adequacy of the analytical model, material properties of the structures and the analytical method used for the seismic design. (orig./HP)