The public comment period on a proposed plan to move radioactive capsules to a new storage location area within the Hanford Nuclear Waste Site in southeast Washington is coming to a close.

Under the proposal, the U.S. Dept. of Energy Richland Operations Office plans to transfer radioactive cesium and strontium isotope capsules from a concrete pool to a cask storage system located on a concrete pad within the 200 East Area of Hanford.

The public has until the end of January to comment on the proposed modification to the Hanford Dangerous Waste Permit.

From 1974 to 1985 the radioactive cesium and strontium isotopes recovered from high-level waste tanks were placed in stainless steel capsules and stored in concrete pool cells at the Waste Encapsulation and Storage Facility. That’s where the capsules remain today.

The 1,335 cesium chloride capsules and 601 strontium fluoride capsules need the water in the pool to protect workers from high levels of radioactivity and help keep the capsules cool.

The DOE proposes moving the capsules to an interim dry storage location in a concrete and steel cask storage configuration to eliminate any risk of the pool water draining in what is considered an aging facility.

The cask system naturally heats from the cesium and strontium, but is designed to passively cool by using airflow within the cask. Cool, clean air gets drawn in, while the warm air moves out, without the need for fans or mechanical equipment. Since the capsules remain sealed within the cask and don’t come into contact with the air, no radiation gets released during the process. This same passive cooling approach is used for dry storage of used nuclear fuel at other DOE locations and the concrete and steel provide “robust shielding to protect workers and eliminate the possibility of a release of radioactive material,” DOE says in materials explaining the process.

As work continues on cleaning the nuclear waste site of its radioactivity, no final decision on how to dispose of the capsules has yet been made.

Follow Tim Newcomb on Twitter at @tdnewcomb.