「もんじゅ」温度計の流力振動

Abstract

In December 1995, a thermocouple well was broken at the prototype fast breeder reactor Monju. In this paper, numerical simulation and water experiment of the flow-induced vibration of the thermocouple well are presented. Both the analysis and the experiment identified an in-line oscillation and the symmetric vortex shedding at the rated 100% flow condition. Furthermore, it has been found that the in-line oscillation takes place at decreased flow rate if the natural frequency of the thermocouple is reduced.