A tall double fence topped with loops of lethal razor wire still surrounds key portions of Hanford's Plutonium Finishing Plant.

But guards toting automatic weapons are gone. The X-ray machines and metal detectors more powerful than those used at airports have been ripped out of the building's entrance.

And there's no one left behind the thick bullet-proof glass of the security center keeping an eye on those arriving at the plant. Instead, the glass has been plastered with stick-on Christmas decorations.

Until recently the Plutonium Finishing Plant was one of the most secure places in the nation, said Matt McCormick, Department of Energy assistant manager for central Hanford.

But Thursday, media and community leaders were invited inside for a rare look at the vaults where plutonium was once stored. At the same time, employees of the plant celebrated shipping out the last of the high-security material stored at the plant, including plutonium, for storage or disposal elsewhere.

About two-thirds of the plutonium for the nation's nuclear weapons program passed through the plant during the Cold War.

Fuel was irradiated at Hanford reactors, the plutonium was separated from the fuel at the nuclear reservation's processing plants and then it was formed into metal buttons the size of hockey pucks at the Plutonium Finishing Plant to be shipped off-site for conversion to weapons use.

"The gates are down at PFP," Dave Brockman, manager at the DOE Hanford Richland Operations Office, said Thursday at the employee celebration.

Many of the men and women who gathered outside the plant to hear congratulations had a significant part in winning the Cold War, he said.

Clearing the plant of high security materials is a step toward getting the buildings cleaned out to tear down within the next few years as part of the environmental cleanup of the nuclear reservation.

"The plant is probably the largest risk to human health and environment" among the buildings in central Hanford, Brockman said.

Workers aren't yet accustomed to seeing tour groups being led across the grounds.

"This is really weird," said Mike Bowles, a nuclear chemical operator for CH2M Hill Plateau Remediation Co., as he showed one group the room packed with glove boxes where plutonium was packaged before it was placed in the vault. It was the first time he had talked about the work done there to anyone who did not have security clearance.

"For the last 10 years work stayed at work," he said. "You didn't talk about it."

For eight of his 10 years at the Plutonium Finishing Plant, he worked inside the building that held the main vaults.

To reach it, workers first go through the main security check point, complete with the X-ray machines, metal detectors and radiation detectors -- the latter to make sure they weren't carrying any radioactive materials when they left the plant.

Then they'd pass through a second security check point to enter the separate building that contained the main set of vaults. They'd go through another metal detector and slip their credentials through a slot to another security officer sitting behind a small glass window.

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 hold what employees call "wine racks." Coffee-can-sized canisters holding plutonium were laid on their sides like wine bottles in the racks.

Removing a canister, which could weigh 20 pounds, required a convoy: Guards, two to four nuclear chemical operators, one to two radiological control technicians, a supervisor and a nuclear material safeguard specialist, said Bob Leonard, CH2M Hill decontamination and decommissioning manager for central Hanford.

The canister would be carried to a red wagon, about the size of a child's wagon. But welded on it were carefully spaced holders for the canisters to make sure they were spaced far enough apart to prevent a criticality.

They'd be rolled through the building to be packaged in shipping containers. A "two person" rule was in effect in the rooms where that packaging was done to make sure no one was ever alone with the plutonium.

"I'm going to miss it," Bowles said, now that he'll move on to preparing the plant for demolition. "It was steady work. You knew what you were doing every day."

DOE, CH2M Hill and Washington State Department of Ecology leaders, as well as staff from Washington's congressional delegation, each told workers Thursday that they should be proud of what they had accomplished.

"But I'm sure it's bittersweet in some ways for those of you who have been here many years and had family here," said Jane Hedges, manager of the state's Nuclear Waste Program.

About 900 people work at the plant, including more than 100 hired with federal economic stimulus money.