The calciner is a waste treatment facility at the INL that treated liquid high-level waste, making a solid high-level waste called calcine. It has been the subject of some controversy, because although it does a good thing—turning liquid waste into a solid—it may also emit pollution.

In the calciner, a fine mist of liquid waste is sprayed into a heated chamber containing beads the size of coarse sand. The chamber circulates the beads like an air popcorn popper, and the heat evaporates the water from the liquid waste, which forms a coating on the beads. The continued popcorn popper motion constantly chips the coating off the beads, forming flakes. The flakes then travel through transport tubes to storage bins.

Smoke drifts from the stack of the calciner in this file photo. The calciner has not operated since May 27, 2000.