Sodium Hydroxide

Radioactive Waste Stream Recycling

Nasicon Module Undergoing Testing

Problem: The Department of Energy’s (DOE) is chartered to provide treatment and disposal of radioactive mixed waste. Each waste stream will be vitrified into suitable waste forms for near surface disposal and deep geologic disposal.

The Treatment Plant will require a processing step to remove the Alumina sludge from the waste by a leaching process that utilizes large amounts of sodium hydroxide. As the amount of sodium added in the form of sodium hydroxide approaches the base sodium in the waste inventory, The NaSelect technology will allow for recovery and recycling of the available caustic inventory to reduce the overall sodium load.

Solution: Ceramatec’s patented technology can remove sodium from sodium salts containing low activity waste and make caustic for reuse on site. This concept employs a sodium super ionic conductor membrane (NaSelect membrane) based electrolytic cell process operating at temperatures below which will selectively remove sodium from low-level and supplemental waste streams to form concentrated caustic.

Modular Electrolysis System

Benefits: (1) Potential to reduce handling, processing of waste and Time Schedule. (2) Potential cost savings for waste cleanup by lowering volume of waste.

The process regenerates the sodium in the form of “sodium hydroxide” for reuse on site. NaSICON ceramic membrane technology will directly make sodium hydroxide up to 50 wt% and prevents migration of mono valent and multi valent elements and other radionuclides to the sodium hydroxide stream.

The sodium ionic conductivity reaches 10^-1 S/cm at temperature approaching 100C and membrane technology is suitable for application approaching up to 150C.

Tubular NaSelect Cell configuration adds reliability and robustness for system operation withstand differential pressures in the 250 to 500 psi range.