Le beton de ponce utilise comme isolant thermique des caissons en beton precontraint dans les centrales nucleaires E.D.F.

In erecting the prestressed concrete pressure vessels used for natural uranium, graphite moderated, gas cooled reactors, the designer is faced with the important difficulty of the thermal insulation for the prestressed concrete vessel. For its power plants, E.D.F. 3 at Chinon and E.D.F. 4 at Saint-Laurent-des-Eaux, Electricité de France has used an insulating material, specially studied and developed for this purpose: pumice concrete. A brief recapitulation of the properties needed for insulating the reactor pressure vessels is given here, followed by detailed information on the nature and the source of the pumice concrete components, the process and manufacture checkings and its use in the reactor, and indications concerning principal mechanical and thermal properties. Finally, instructions are given on how to put the pumice concrete to various uses.