Secret nuclear vault at Hanford cracked open. They weren’t sure what they’d find

Hanford workers in protective gear were prepared for any possibility when a secret and historic vault in the center of the site recently was pried open.

During World War II as Hanford workers raced to produce plutonium for atomic weapons, the Plutonium Metallurgy Laboratory or “Isolation Building” was used to purify eight-gallon batches of plutonium nitrate.

The finished “product” — as plutonium was code named — would be sent to Los Alamos, N.M., to be made into a form for weapons use, including the bomb dropped on Nagasaki, Japan.

The final step for the plutonium at Hanford during WWII through the mid-50s was to pack it in shipping boxes twice the size of a shoe box and then lock it away in a vault in one corner of the Isolation Building until it could be shipped.

“It was heavily fortified and guarded, and very few people had access or even knowledge of it,” said Rick Raymond, an engineering manager with Department of Energy contractor Central Plateau Cleanup Co.

Preparations are being made now to demolish the building, which stands about 300 yards north of the former Plutonium Finishing Plant.

“We believed the vault to be empty, but we needed to be sure before proceeding with cleanup activities,” Raymond said.

The vault had not been opened in 20 years.

Hanford locksmiths were called in to drill through the heavy metal door. Then workers used a pry bar to open the door and allow Hanford workers in protective equipment and respirators to enter.

They found an empty room, with little more than a light fixture hanging overhead.

But confirming the vault was empty is one more step completed in preparations to allow the building to be demolished by 2025.

The Hanford nuclear reservation in Eastern Washington continued to be used through the Cold War to produce nearly two-thirds of the plutonium for the nation’s nuclear weapons program.

But the Isolation Building was no longer needed as part of the plutonium production process after the Plutonium Finishing Plant began operating in 1956.

This story was originally published October 7, 2021 at 12:40 PM with the headline "Secret nuclear vault at Hanford cracked open. They weren’t sure what they’d find."