New ventilation system required to shut down Hanford radioactive capsule storage

The Department of Energy is making plans to replace the ventilation system at Hanford’s Waste Encapsulation and Storage Facility, a necessary step to shut down the building.

Earlier this year, DOE’s Office of Inspector General said that 1,936 capsules of radioactive cesium and strontium stored at the facility, called WESF, should be moved to dry storage as soon as possible, in part because of the potential risk posed by a severe earthquake.

Now the capsules are stored under 13 feet of water at WESF, which was built for them at the west end of B Plant between 1971 and 1973.

But the ventilation system that was used when work was done to place the waste in capsules is no longer up to the task of ensuring air is clean and safe when the capsules are processed to be moved to dry storage, according to DOE documents.

The filters have operated longer than they were planned to and are deteriorating. And the work done with radioactive materials has contaminated the ventilation system.

Although a new system will be installed to ensure continued safe operations at WESF, DOE is making plans to cut costs by installing a smaller system.

That would be accomplished by reducing the space in the building by filling all but one of the seven hot cells served by the ventilation system with grout.

The ventilation system also would be filled with grout. A public meeting on the issue is planned Jan. 7 in Richland.

The seventh hot cell is on standby in case one of the underwater capsules develops a leak or other issue that would require it to be pulled from the water for work. The hot cell also is tentatively planned to be used to process the waste when DOE is ready to move it to dry storage.

Most of the hot cells measure about 8 feet long and 8 feet high and up to 13.5 feet tall. The floors and walls are lined with stainless steel and workers would look through 25-inch-thick lead glass windows and operate manipulators inside the cells that handled the radioactive materials.

Starting in 1974, the hot cells were used for radioactive cesium and strontium that had been separated from other waste in Hanford’s underground storage tanks to reduce the heat in the tanks. Within the hot cells, the material was packed into stainless steel canisters about 21 inches long.

Six of the hot cells were cleaned out and prepared for closure previously. However, some waste was left stored in them.

That includes two containers of floor sweepings containing some strontium, which was collected during the last steps of shutdown of operations in the hot cells. The containers are about the size of flower pots, said Mandy Jones a permit coordinator for the Washington State Department of Ecology.

Some debris also was swept into piping that has been closed at each end and mounted on the walls, said Suzanne Dahl, manager of the Department of Ecology’s tank waste treatment section.

Because the manipulator arms were removed from the six hot cells and electricity service was cut earlier, DOE is requesting that the state allow the waste to be left in the hot cells as they are filled with grout.

Normally, the waste would be required to be removed and treated for disposal separately.

After the cesium and strontium capsules are removed from WESF, DOE could cut the grouted cells into blocks to be disposed of or the building could be treated as part of the processing plant it’s connected to, B Plant. At processing plants, walls may be collapsed and then an earthen barrier built over the demolished building to keep out water that could spread contamination.

“Ecology supports the idea that ventilation needs to be grouted and understands the need to take interim steps in the hot cells,” Dahl said.

It also supports the need to put cesium and strontium into dry storage.

DOE does not yet have a date for that work or money budgeted for it.

Bids had been requested in 2003 to start repackaging and then putting the capsules in dry storage in Hanford’s T Plant in late 2005. However, the work was canceled as DOE decided it had more pressing environmental cleanup concerns.

Moving the capsules to dry storage is crucial because a national repository will not be available for them for decades, the Office of Inspector General said in an April memo. The capsules hold about a third of the total radioactivity at Hanford and had been planned to be sent to the proposed repository at Yucca Mountain, Nev., for disposal.

The memo called WESF the DOE facility at greatest risk in the case of a natural disaster that exceeds design standards.

The concrete in the cells of its underwater pools has begun to deteriorate from radiation exposure, and a severe earthquake could result in the loss of water used to cool the capsules and provide radiation shielding.

The memo acknowledged that an earthquake more severe than WESF was designed to withstand is not likely and that money will not be immediately available to move the capsules to dry storage. But it urged DOE to make plans for dry storage as soon as possible, both for safety and to reduce the annual $7.2 million cost of storing the capsules underwater.

A public meeting on permit modifications for grouting the hot cells and their ventilation system is planned at 5:30 p.m. Jan. 7 at the Richland Public Library, 955 Northgate Drive. Hanford officials are not discussing costs for the new ventilation system while parts of the project are being bid.

Public comments also may be sent through Feb. 12 to Hanford@ecy.wa.gov or to Stephanie Schleif, Washington Department of Ecology, 3100 Port of Benton Blvd., Richland, WA 99354.

This story was originally published December 26, 2014 at 10:37 PM with the headline "New ventilation system required to shut down Hanford radioactive capsule storage."