Research on friction coefficient of nuclear Reactor Vessel Internals Hold Down Spring: Stress coefficient test analysis method

Abstract

This paper performs mathematic deduction to the physical model of Hold Down Spring (HDS), establishes a mathematic model of axial load P and stress, stress coefficient and friction coefficient and designs a set of test apparatuses for simulating the pretightening process of the HDS for the first time according to a model similarity criterion. By carrying out tests and researches through a stress testing technique, P–σ curves in loading and unloading processes of the HDS are obtained and the stress coefficient kf of the HDS is obtained. So, the friction coefficient f of the K1000 HDS are further calculated to be 0.336 by stress coefficient kf. It is very important that the research method of friction coefficient put forward by this paper for the first time. The method can provide an exact basis for HDS design and structure selection and can provide a guarantee for the safe operation of the reactor.