| 摘要 |
The present invention relates to methods for decontaminating radionuclides from neutron-irradiated carbon and/or graphite materials, comprising mechanical and/or chemical treatment methods. The mechanical treatment methods comprise the steps of fracturing, shaking, and sieving, and the chemical treatment methods comprise the supplying of activation energy and the addition of gaseous decontaminating agents. The addition and treatment with decontaminating agents are performed in a heatable pressure- and/or vacuum-resistant reaction vessel or in reaction chambers arranged one after the other. The methods are characterised by the following steps: a) adding gaseous decontaminating agents, the gaseous decontaminating agents being added at a charging pressure that lies above the atmospheric pressure or with pressure alternations, such as alternations between overpressure with respect to atmospheric pressure and vacuum with respect to atmospheric pressure, so that the ingress of the decontaminating agents into the inner pore system of the neutron-irradiated carbon and/or graphite material is accelerated with respect to addition at constant atmospheric pressure, b) flushing the reaction vessel or the reaction chamber with inert gas at preferably the same charging pressure as in step a) or at pressure reduced down to the atmospheric pressure in order to largely leave the decontaminating agent in the pore system, c) heating to T > 300 °C under atmospheric pressure conditions, d) extracting the formed gases from step c) by applying a vacuum to the reaction vessel or the reaction chamber and capturing the released radioactive gases, e) iteratively repeating at least one of steps a) to d) until radionuclides cannot be detected or can be detected only up to a desired concentration in the gas analysis of the extracted gases from step d). The invention further relates to a method in which a liquid decontaminating agent is used. |
