SEOUL – South Korea’s state research institute has developed an innovative technology to recycle low-level radioactive waste. If commercialized, the technology can lower the cost of disposing of radioactive waste or buying expensive neutron absorbers.
The Korea Atomic Energy Research Institute (KAERI) announced that its research team has converted low-level radioactive waste into boron carbide to prevent a fission chain during transport and storage, or into neutron absorbers. Nuclear power plants use activated carbon to purify the air and boric acid as a reactor moderator.
South Korean nuclear power plants store 5,000 barrels of used activated carbon and 20,000 barrels of dried powder with boric acid. The institute said that applying the technology to 25,000 drums of low level radioactive waste stored in domestic nuclear power plants could save up to 300 billion won in disposal costs.
“Just as general industrial waste is recycled, radioactive waste can bring great innovation to radioactive waste management in South Korea,” said Park Hwan-seo, a senior KAERI researcher, in a statement April 13. Commercial use is possible through further research, he said.
The new method can reduce the cost of buying expensive neutron absorbers, which are used to control the performance of a reactor or prevent a fission chain when storing and transporting nuclear material, the Park team said.
Activated carbon has the properties of heating when absorbing microwaves. When a high-powered microwave oven quickly heats spent activated carbon and dried boric acid waste to 1,500 degrees Celsius or higher, most substances except carbon and boron are separated by volatilization, the team said. Carbide is a representative substance with excellent neutron absorption. Carbon and boron can be synthesized into boron carbide (B4C) and used as neutron absorbers.
The amount of waste can be further reduced by using extremely low-grade metal scraps generated during operation and dismantling to support neutron absorbers, the research team said, describing its technology as a new method that has value for synthesis, reconstruct and use three different radioactive wastes.
If the new technology is used in the dry storage of spent fuel elements, the cost of purchasing neutron absorbers can be reduced and the disposal of used neutron absorbers can be eliminated. Nuclear waste is a tough issue due to a US reprocessing ban to prevent its possible proliferation in Northeast Asia.
Used fuel rods are initially stored in storage basins with water, which provide cooling and shielding against radiation. After 7 to 10 years of wet storage, they can be transferred to storage. For technical and political reasons, South Korea has no intermediate storage or permanent disposal facilities. The spent nuclear fuel was stored in interim storage facilities.
Environmental associations have spoken out against the construction of additional facilities. Korea Hydro & Nuclear Power (KHNP), the state operator of nuclear power plants, has requested a quick solution. The storage facilities would no longer have space for the storage of nuclear waste in March 2022.
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