Updated

If you were driving east on I-40 in Amarillo, you might not even notice the large group of buildings set back from the road or the unfamiliar name Pantex -- but beyond the barbed wire, the nation’s nuclear weapons are being assembled and disassembled largely out of the public eye.

It’s the only facility of its kind in the country -- “the center of the nuclear weapons universe,” as one federal official said -- so training a security force to handle any potential threat is almost as critical as the work done on the weapons.

When the U.S. agrees to get rid of part of its nuclear arsenal, it comes here. The same holds true for current weapons that need to be maintained or refurbished. Contemplate the sheer magnitude of the weapons and nuclear material coming through the gates of the facility and you begin to get an idea of why security is so important at Pantex.

That’s why there’s a 500-member paramilitary force guarding the plant. These individuals have a unique way to make sure their skills are up to snuff. Fox News got a rare peek inside their training.

After surrendering cell phones, cameras and a list of other prohibited items, guests to the plant must check in with photo identification and proof of U.S. citizenship. There’s a security briefing and then a winding drive through checkpoints to arrive at the virtual security training center. Step inside and it takes a few minutes for your eyes to adjust to the light. Then you see the guns. And the humvee. These are facing large movie-like screens that run from floor to ceiling and wall to wall. Trainers can project different scenarios on the screens while security officers are put through the paces. The guns feel real because they are.

But instead of ammo, they’re outfitted with compressed air so they will they feel real when they’re shot. There are also cameras to record the training so that the officers can receive feedback once it’s finished.

The two large rooms in the virtual training facility can run simultaneously and in coordination. So while one set of officers is “driving” the humvee and shooting a grenade launcher from its roof, they can “see” the other officers training in the next room, who are armed and on foot. Likewise, the officers on foot can see the humvee. The whole thing is like a life-sized video game on steroids.

Why not just save the expense of building a facility like this and hit a shooting range? As David Smith, the program’s manager explains it, this facility actually saves money. “We wanted to go beyond a live-fire range,” says Smith. Every time a real weapon is fired, expensive ammunition is used.

And who could blow up vehicles on a range? Here, they can be blown up or shot at again and again. Officers can go through different scenarios thousands of times.

It’s all to prepare for what everyone hopes never happens, an attack on the plant.

“Their presence is a pretty good deterrent," Steve Erhart, the lead federal administrator at the site, said. Still, everyone has to be prepared for the worst. “We’re on the pointed end of the stick. ... We come to work with that on our mind.”