Treatment method of recommissioned radioactive nuclear graphite
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A processing method and radionuclide technology, applied in the field of radioactive graphite processing, can solve problems such as environmental and human harm
Pending Publication Date: 2021-08-13
BEIJING JIAOTONG UNIV
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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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Embodiment 1
[0033] Take 10g of nuclear graphite and pulverize it into a powder smaller than 250um after being pulverized by a disc mill, weigh 1%wt analytical pure AlCl 3 Mix with nuclear graphite powder, the mixing method is planetary ball mill, the speed is 180r / min, the mixing time is 1h, the heat treatment is carried out in a tube furnace, the temperature is 800°C, the heating rate is 10°C / min, and the atmosphere is 90% argon Gas+10%O 2 , the gas flow rate is 100ml / min. After the temperature rises to the specified temperature, quickly put the crucible containing the mixed powder into it, and the heating time is 2 hours. The heat treatment equipment is connected with a condensation device, so that the temperature of the volatilized metal chloride drops below the dew point and condenses as After the particles are collected, the decontamination of the radioactive metal isotopes in the nuclear graphite is completed. The equipment is connected with an alkali washing pool and condensation e...
Embodiment 2
[0035] The treatment method of the decommissioned radioactive graphite in this embodiment is the same as in the first embodiment, except that the heat treatment temperature is 900°C.
Embodiment 3
[0037] The processing method of the decommissioned radioactive graphite in this embodiment is the same as that in Embodiment 1, except that the heat treatment temperature is 1000°C.
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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...
Claims
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