Session: SE-05-01 Structural Dynamics

Paper Number: 105872

105872 - Seismic Response of Tubes Vibrating Independently in In-Plane Direction for U-Shaped Tube Bundle With Triangular Arrays in Steam Generators 

Ensuring a complete integrity of steam generators’ tubes during earthquakes is critical. In order to predict the vibration behavior of tube bundle in in-plane direction, seismic tests for U-shaped tube bundle with square arrays had been carried out. During the tests, vibrations were observed in the tube bundle at the location where the tubes and the AVBs vibrate as a whole structure. Independent vibrations for some tubes were also observed at the location where the tubes slide with the AVBs and impact with the adjacent tubes. As for the seismic design, carrying out an evaluation of the tube stress for independent vibrations was sufficient, because the maximum stress of the tubes was much larger than that of the tube bundle vibration.

Since tube bundles with triangular arrays have different tube pitches, seismic excitation tests were carried out for this study, to grasp the vibration characteristics of the tubes in in-plane direction. Independent vibrations were observed for some tubes during the tests. The effects of the excitation level, the dominant frequency of excitation wave and the bending radius on independent vibration characteristics were investigated. The damping ratio of independent vibrations is mainly caused by friction force at low velocity, and by impact force with adjacent tube at high velocity. Tube stress of the independent vibration was calculated using the minimum damping ratio obtained from the tests. It was concluded that the calculation can conservatively evaluate the stress of tubes vibrating independently by comparing with the test results.

Presenting Author: Tomonori Mineno Mitsubishi Heavy Industries, Ltd.

Presenting Author Biography: I graduated from Kobe University, Master’s degrees of Mechanical Engineering in March 2008.
I joined Nuclear Plant Component Designing Department, Kobe Shipyard & Machinery Works, Mitsubishi Heavy Industries, Ltd in April 2008.
Since April 2020 I have been a senior deputy manager of Reactor Component Designing Section, Nuclear Energy Systems, Mitsubishi Heavy Industries, Ltd.

Authors:

Masatsugu Monde Mitsubishi Heavy Industries, Ltd.
Naoki Ono Mitsubishi Heavy Industries, Ltd.
Tomohito Nakamori Mitsubishi Heavy Industries, Ltd.
Kazuo Hirota Mitsubishi Heavy Industries, Ltd.
Masahito Matsubara Mitsubishi Heavy Industries, Ltd.
Tomonori Mineno Mitsubishi Heavy Industries, Ltd.
Koshi Taguchi The Kansai Electric Power Company, Incorporated