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How can cement help immobilize low-level radioactive waste?

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Labeled diagram showing the process of a nuclear power plant with a pressurized-water reactor. Water circulates through the reactor core, heats to produce steam in a steam generator, which drives a turbine connected to an electric generator. Steam is then cooled in a condenser using water from a cooling tower, which releases nonradioactive water vapor. Control rods, pumps, and transmission lines are also indicated. — nuclear power Schematic diagram of a nuclear power plant using a pressurized-water reactor.

Cement is used to immobilize low-level radioactive waste (LLW) by converting liquid or sludge-based waste into a solid form, which helps prevent environmental contamination from potential leaks.1

The immobilization process occurs through two primary mechanisms:

Chemical Incorporation: Certain radioactive species are chemically integrated into the cementitious product phases as the mixture hardens.1
Physical Entrapment: The remaining radioactive materials are trapped within the pores of the cement paste.1

By utilizing microstructurally engineered cements, engineers can achieve extremely low permeability, which significantly reduces the rate at which radioactive elements can leach out of the material. This method serves as a critical safety measure for managing the aqueous solutions and sludges that accumulate during the processing of nuclear fuels and wastes.1