Patent Number: 
Section: claims

1. Composite material for neutron shielding and maintenance of sub-criticality comprising:(a) a matrix based on vinylester resin comprising at least one compound chosen from the group consisting of epoxyacrylate vinylester resins, epoxymethacrylate vinylester resins, bisphenol A type vinylester resins, novolac type vinylester resins, halogenated vinylester resins based on bisphenol A, and vinylester resins obtained from isophthalic polyester and urethane; and(b) an inorganic filler capable of slowing and absorbing neutrons, the inorganic filler comprising at least one inorganic compound of boron and at least one hydrogenated inorganic compound. 2. Material according to claim 1 in which the vinylester resin is an epoxy(meth)acrylate bisphenol A type resin complying with the following formula:in which R represents H or CH3. 3. Material according to claim 1 in which the vinylester resin is a novolac resin of formula:in which R represents H or CH3. 4. Material according to claim 1 in which the inorganic compound of boron is chosen from the group consisting of boric acid H3BO3, zinc borates Zn2O14.5H7B6, Zn4O8B2H2 and Zn2O14B6, colemanite Ca2O14B6H10, boron carbide B4C, boron nitride BN and boron oxide B2O3. 5. Material according to claim 1 comprising at least one boron compound chosen among the group consisting of zinc borate Zn2O14.5H7B6, and born carbide B4C. 6. Material according to claim 1 in which the hydrogenated inorganic compound is chosen from the group consisting of alumina hydrates and magnesium hydroxide. 7. Material according to claim 1 in which the quantities of inorganic hydrogenated compound and inorganic compound of boron are such that the boron concentration in the material is equal to 8×1022 to 15×1021 of boron atoms per cm3 and that the hydrogen concentration is 4×1022 to 6×1022 atoms per cm3. 8. Material according to claim 1, comprising 25 to 40% by weight of vinylester resin. 9. Material according to claim 1, with a density equal to or greater than 1.6, preferably 1.65 to 1.9. 10. Material according to claim 1, which can resist a minimum usage temperature of 160° C. 11. Process for preparation of a composite material according to claim 1, including the following steps:prepare a mix of vinylester resin in solution in a vinyl thinner with the inorganic filler,add a catalyst and an accelerator for hardening to the mix,degas the mix under a vacuum,pour the resulting mix in a mould, andallow the resulting mix to set in the mould. 12. Process according to claim 11, in which the vinyl thinner is styrene. 13. Process according to claim 11, in which the mould is a transport and/or storage packaging for radioactive products. 14. Transport and/or storage packaging for radioactive products comprising a shield formed from a composite material according to claim 1.