Supernate solidified for safe storage

Researchers have discovered a new method of processing low-activity liquid nuclear waste into a stable solid for safe disposal.

The team of scientists from PennStateUniversityand the Savannah River National Laboratory found a way of solidifying and stabilising high alkali, low-activity radioactive waste at low temperatures of 90°C or less. The resulting form is a hydroceramic, which is strong, durable and has the potential to contain minor radioactive components in its zeolitic structure. A zeolyte is a silicate mineral that can attract and trap certain chemicals.

The US Department of Energy (DOE) currently holds millions of litres of liquid radioactive waste at underground facilities. It consists of highly radioactive sludge with far less radioactive supernate, the liquid that remains once the solid settles. The sludge can be vitrified, and this new process gives an option for safely storing the supernate.

Once emptied, the storage tanks will be cleaned and filled with a cement-like compound that renders them safe.