HANFORD — Hanford workers are ready to pull the last glove box out of the Plutonium Finishing Plant's vault complex, clearing the way for demolition of a building that was one of the nation's highest security structures.
For almost four decades, the plant turned plutonium produced in Hanford reactors into metal buttons the size of hockey pucks for shipment to the nation's weapons production plants. More than half the nation's plutonium for nuclear weapons came through the plant.
The final stop for plutonium at the plant during the last years it operated was the vault complex. There, plutonium could be assayed in two glove boxes and packaged in seven other glove boxes. Excess material also was stabilized there.
Then the plutonium, packaged in metal canisters, was stored in vaults until it was shipped off-site for conversion to weapons use.
From the outside, the vaults look like those at banks, with heavy steel doors that slowly swing open when pulled.
Inside are narrow aisles lined with floor-to-ceiling lockers. They held what employees called "wine racks." Coffee-can-sized canisters holding plutonium were laid on their sides like wine bottles in a rack.
The storage vaults were built in 1971, and in 1983 an annex, the ZB Building, was finished just six years before plutonium processing stopped. It housed the nine glove boxes.
Security for the plant required workers to enter through razor-wire-topped fences and then walk through metal detectors. To get into the vault complex, they had to enter a separate security area inside the plant, which had metal and plutonium detectors. Anyone who then entered the vault had to be accompanied by an armed Hanford patrolman, who would ask for a secret code.
The last of the weapons-grade plutonium has been removed and the entire plant is scheduled to be demolished in 2013, three years ahead of the legal deadline.
Removing the final glove box from the vault complex will be a significant accomplishment in a long and difficult process, said Dieter Bohrmann, spokesman for the Washington State Department of Ecology, the project's regulator. Work is being done with federal economic stimulus money.
In a major step to prepare the vault complex for demolition, CH2M Hill Plateau Remediation workers needed to clean out the shielded glove boxes, where workers would insert their hands into gloves attached to portals to work with radioactive material.
The boxes had furnaces attached that were used to heat the plutonium to stabilize it, and CH2M Hill workers removed the related equipment inside the boxes. They also cleaned out packaging equipment, such as welders and empty cans, and laboratory equipment, such as beakers and scales, said Jenna Coddington, CH2M Hill spokeswoman.
Then the interior walls of the glove boxes were decontaminated with chemicals and sprayed with a fixative to keep any remaining radioactive contamination in place. Next, the chemical process lines and ventilation systems were detached and the legs of the glove boxes cut off.
The combined size of the glove boxes was 400 cubic feet, and each was large enough that part of a building wall had to be cut out to allow them to be wheeled outside.
Four of the glove boxes are being packaged and disposed of in a central Hanford landfill for low-level radioactive waste. Five of them still contain enough plutonium contamination that they will need to be sent to the Waste Isolation Pilot Plant in New Mexico for disposal.
The last glove box is waiting to be wheeled out of the building Monday, Coddington said.
"This is exciting for us," she said. "Once we get it out, we are pretty darn close to demolition."
As soon as the ventilation piping between the glove boxes and filter is removed, the power will be turned off and the vault complex will be turned over to the demolition crew, Coddington said.
The vault area will be demolished with the plutonium racks in place, unless the Department of Energy directs some of them to be saved because of their historic significance.
Demolition is planned in the spring.
"A little over a year ago, it was one of the most highly secured buildings in the nation and now it's going to be gone," Coddington said.
* Annette Cary: 509-582-1533; firstname.lastname@example.org; more Hanford news at hanfordnews.com.