Composite Materials Use: A Particular Case of Safety-Related Service Water Pipes

Abstract

This paper shows the present and future uses of composite materials in French nuclear and fossil-fuel power plants. It sets the EDF composite materials market in the general composite materials market and shows the great interest that EDF takes in these materials which are corrosion resistant in most fluid handling applications. Electricité de France has decided to install composite materials in service water piping in its nuclear power plant (PWR) at Civaux (West of France) and for the first time in France, in safety-related applications. Our requirements are thus much more severe than is usually the case and the choices (for the basic materials, the manufacturing, the design rules, and the non destructive testing methods) have to be justified before our Safety Authorities. A wide range of studies has been performed about the durability, the control and damage mechanisms of those materials under service conditions among an ongoing Research and Development project. The main results are presented under the following headlines: • Selection of basic materials and manufacturing processes, • Aging processes (mechanical behavior during « lifetime »), • Design rules, • Non destructive examination during manufacturing process and during operation. The studies have been focused on epoxy glass pipings: the actual application is the circuits for the nuclear power plant in Civaux, the supplies and installation of the pipes have largely begun. We underline the importance of strong quality insurance policy requirements towards production and installation companies. We present a study of the use of composite pipes in power plants (hydraulic, fossil fuel, and nuclear) in France whether it be safety related or non safety-related applications. We present the different technical solutions for materials and manufacturing processes and an economic comparison between steel and composite pipes. Finally, we give the general conclusions of the R&D program.