Abstract: Disclosed is a method for treating an absorber pin, wherein the pin comprises a cladding in which a sintered boron carbide-based material having cracks is located, the material having porosity less than 1% of the volume of the material, the cracks containing sodium and at least one radioactive material. The method includes contacting the material with a treatment reaction mixture including carbon dioxide and water, in such a manner that the production of sodium carbonate and the expansion thereof cause the opening of cracks and of the sheath from at least one slit provided in the sheath as well as the propagation of the treatment process within the material. The process overcomes the physical-chemical properties of a sintered boron carbide-based material as much as possible. These properties prevent an easy treatment of the sodium and radioactive material contained in the cracks of the material.

Abstract: Disclosed is a method for treating an absorber pin, wherein the pin comprises a cladding in which a sintered boron carbide-based material having cracks is located, the material having porosity less than 1% of the volume of the material, the cracks containing sodium and at least one radioactive material. The method includes contacting the material with a treatment reaction mixture including carbon dioxide and water, in such a manner that the production of sodium carbonate and the expansion thereof cause the opening of cracks and of the sheath from at least one slit provided in the sheath as well as the propagation of the treatment process within the material. The process overcomes the physical-chemical properties of a sintered boron carbide-based material as much as possible. These properties prevent an easy treatment of the sodium and radioactive material contained in the cracks of the material.

Abstract: A method for treating a cladding within which there is a sintered material composed wholly or partly of sintered calcium hydride, the method comprising a step during which the sintered material is contacted with a reaction mixture comprising steam, carbon dioxide, and a chemically inert gas, the contacting being carried out for a duration allowing the sintered calcium hydride to be converted into a calcium carbonate powder. The treatment method provided by the invention results in a chemically inert waste, a limitation on the volume of wastes obtained, while allowing the removal or even recovery of these wastes by appropriate processing streams.

Abstract: A method for treating a cladding within which there is a sintered material composed wholly or partly of sintered calcium hydride, the method comprising a step during which the sintered material is contacted with a reaction mixture comprising steam, carbon dioxide, and a chemically inert gas, the contacting being carried out for a duration allowing the sintered calcium hydride to be converted into a calcium carbonate powder. The treatment method provided by the invention results in a chemically inert waste, a limitation on the volume of wastes obtained, while allowing the removal or even recovery of these wastes by appropriate processing streams.

Abstract: Method of treating sodium contained in the interconnected open pores of a structure placed in a cladding, the pores furthermore containing a radioactive substance. The method comprises the following successive steps: a) at least two slits are made over the entire length of the cladding; b) the sodium is converted to sodium carbonate by a carbonation reaction by bringing the structure into contact, via the slits, with a reactive gas mixture comprising steam, carbon dioxide and a gas inert with respect to sodium, in such a way that the expansion of the carbonate causes the cladding and the structure to open starting from the slits and results in the carbonation reaction propagating into the structure.

Abstract: Method of treating sodium contained in the interconnected open pores of a structure placed in a cladding, the pores furthermore containing a radioactive substance. The method comprises the following successive steps: a) at least two slits are made over the entire length of the cladding; b) the sodium is converted to sodium carbonate by a carbonation reaction by bringing the structure into contact, via the slits, with a reactive gas mixture comprising steam, carbon dioxide and a gas inert with respect to sodium, in such a way that the expansion of the carbonate causes the cladding and the structure to open starting from the slits and results in the carbonation reaction propagating into the structure.