Treatment method of recommissioned radioactive nuclear graphite

Abstract

The invention relates to the technical field of radioactive graphite treatment, in particular to a treatment method for treating radioactive graphite. The treatment method comprises the following steps: step 1, crushing a decommissioned nuclear graphite block into powder to obtain nuclear graphite powder; step 2, weighing a certain amount of chlorine source, and mixing the chlorine source with the nuclear graphite powder; and step 3, heating the powder mixed in the step 2 under the mixed atmosphere of inert gas and oxygen for heat treatment. The decommissioned nuclear graphite and a certain amount of chlorine source are mixed and then are heated in an oxygen-containing atmosphere, <14>C is combined with oxygen to form CO and CO2 gases, a large amount of inert graphite matrixes are reserved, <3>H reacts with chlorine elements and the like under the action of high temperature to generate HCl, the radioactive metal in the nuclear graphite can react with the chlorine element to generate a metal chloride with a lower boiling point, and the metal chloride is volatilized at a certain temperature, so that the metal chloride is separated from the nuclear graphite, generated CO2, HCl and gaseous chloride are treated after heat treatment, concentration and enrichment of nuclides are completed, and the decontamination effect of various nuclides of the nuclear graphite is achieved.

Description

technical field [0001] The invention relates to the technical field of radioactive graphite treatment, in particular to a treatment method for radioactive graphite. Background technique [0002] Nuclear graphite generally refers to all synthetic graphites used as moderators, reflectors or other structural materials in reactors. As of now, there are about 250,000 tons of radioactive nuclear graphite in the world that need to be treated urgently, which has become the world's largest solid waste. The nuclear graphite in the reactor is exposed to high neutron flux (~5×10 22 n / cm 2 ), containing a variety of radioactive elements, including corrosion products, fission products, and impurities caused by neutron activation: 3 H, 60 Co, 41 Ca, 55 Fe, 59 Ni, 63 Ni, 110m Ag, 109 Cd, 90 Sr, 93 Zr, 99 Tc, 107 Pd, 113m Cd, 121m Sn, 129 I, 133 Ba, 134 Cs, 137 Cs, 147 PM, 151 Sm, 152,154,155 Eu, as well as some uranium and transuranic elements, the radioactive isotopes...

AI Technical Summary

Problems solved by technology

As of now, there are about 250,000 tons of radioactive nuclear graphite in the world that need to be treated urgently, which has become the world's largest solid waste. The nuclear graphite in the reactor is exposed to high neutron flux (~5×10 22 n / cm 2 ), containing a variety of radioactive elements, including corrosion products, fission products, and impurities caused by neutron activation: 3 H, 60 Co, 41 Ca, 55 Fe, 59 Ni, 63 Ni, 110m Ag, 109 Cd, 90 Sr, 93 Zr, 99 Tc, 107 Pd, 113m Cd, 121m Sn, 129 I, 133 Ba, 134 Cs, 137 Cs, 147 PM, 151 Sm, 152,154,155 Eu, as well as some uranium and transuranic elements, the radioactive isotopes in decommissioned nuclear graphite are complex and harmful to the environment and human body. After thousands of years of decay, radioactivity still exists. major challenge

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