Patent Number: 
Section: claims

1. A Method for producing a part made of ceramic material matrix and ceramic material fibres composite material, the method comprising the following successive steps:formation of a fibrous preform by intertwining threads constituted of ceramic material fibres on a contact surface of a support element reproducing the internal and/or external shape of the part to be produced;partial densification of the fibrous preform at a temperature below the melting temperature of the material of the support element and below the melting temperature of the material of the fibres of the preform, said partial densification resulting in a consolidated fibrous preform comprising a matrix volume fraction above 5% and at the most equal to 40% of the matrix volume of the part to be produced;removal of the support element from the consolidated fibrous preform by chemical attack of the contact surface of the material of the support element;densification of the consolidated preform, carried out at a temperature below the melting temperature of the fibres of said preform. 2. The method according to claim 1, wherein the fibrous preform consolidated at the partial densification step comprises a matrix volume fraction at the most equal to 30% of the matrix volume of the part to be produced. 3. The method according to claim 2, wherein the fibrous preform consolidated at the partial densification step comprises a matrix volume fraction at the most equal to 20% of the matrix volume of the part to be produced. 4. The method according to claim 3, wherein the fibrous preform consolidated at the partial densification step comprises a matrix volume fraction at the most equal to 10% of the matrix volume of the part to be produced. 5. The method according to claim 1, wherein the support element is made of silica, preferably made of silica glass. 6. The method according to claim 5, wherein the chemical attack of the support element is obtained using an acid, preferably hydrofluoric acid, or a base. 7. The method according to claim 1, wherein the support element is made of alumina. 8. The method according to claim 1, wherein the support element is made of zirconium oxide. 9. The method according to claim 1, wherein the support element comprises a core that is made of a metal able to withstand the densification temperature of the preform and which is covered with a layer of silica, silica glass, alumina or zirconium oxide. 10. The method according to claim 9, wherein the chemical attack of the support element is obtained by carrying out the chemical attack of the layer of silica, silica glass, alumina or zirconium oxide present on the core using an acid, preferably hydrofluoric acid, or a base. 11. The method according to claim 1, wherein the support element is a hollow element. 12. The method according to claim 1, wherein the support element has an axis of revolution or is of flat shape. 13. The method according to claim 1, wherein the fibres are made of a material selected from carbon and silicon carbide. 14. The method according to claim 1, wherein the matrix is made of a material selected from carbon and silicon carbide. 15. The method according to claim 1, wherein the part made of composite material is a composite material cladding for a gas cooled or sodium cooled fast reactor or for a pressurised water reactor. 16. The method according to claim 1, wherein the part made of composite material is a hexagonal composite material tube for a gas cooled or sodium cooled fast reactor or for a pressurised water reactor.