Effective thermal conductivity of reflective multiplate thermal insulation

Abstract

The roof slab of the sodium-cooled fast breeder reactor must be thermally insulated to reduce the heat flux reaching it from the hot sodium pool of the reactor. The environment, consisting of argon gas laden with sodium vapor and aerosols, does not permit the use of conventional thermal insulation for the roof slab, which comes into contact with the reactor cover gas. This necessitates the development of special types of thermal insulation that can serve inside the reactor cover gas atmosphere. The reflective multiplate thermal insulation concept has been chosen for detailed study. This paper describes initially a theoretical model and its prediction of effective thermal conductivity as a function of various parameters and then gives detailed description of the experimental setup to determine the effective thermal conductivity of multiplate thermal insulation. Some experimental results of the determination of the effective thermal conductivity as a function of temperature and number of plates of insulation are presented.