Security guards at the country's leading nuclear storehouse have been cheating during antiterrorism drills -- perhaps for as long as 20 years, according to a report released Monday by the Energy Department's inspector general.

And now, watchdogs in Congress and beyond are questioning whether the tons of enriched uranium at the Y-12 National Security Complex in Oak Ridge, Tennessee, are really safe at all.

"First off, heads should roll," said Rep. Christopher Shays (R-CT), who chairs the House Committee on Government Reform's National Security, Emerging Threats and International Relations Subcommittee. "I can assure you, my committee will be following up in a very direct way."

Y-12 is America's main facility for processing enriched uranium. It stores nearly all of the country's reserve of about 5,000 "secondaries," the thermonuclear hearts of hydrogen bombs.

When a team of Y-12 rent-a-cops racked up a perfect score during an antiterror drill June 26, officials there were shocked. How could the guards have performed so well, they wondered, when a computer model had predicted that the defenders would lose at least half of their confrontations?

The answer was simple: The guards cheated. They had seen the computer models of the strikes the day before they were launched, rendering the test "tainted and unreliable," according to the report. And this wasn't the first time it had happened.

"From the mid-1980s to the present," contract security guards had been given the plans to the attacks beforehand, noted Inspector General Gregory Friedman. The defenders knew ahead of time "the specific building and wall to be attacked by the test adversary," and they knew "whether or not a diversionary tactic would be employed..."

If that wasn't a big enough advantage, "management would identify the best prepared protective force personnel and then substitute them for lesser prepared personnel," according to the report. "Based on specific attack information, trucks or other obstacles would be staged at advantageous points to be used as barricades and concealment."

The guards got slaughtered the few times they didn't cheat, said Ronald Timm, who spent six years as an independent security analyst at Y-12.

During one test, simulated terrorists took a mock, 44-pound uranium package, and "got outside of the fences in 38 seconds," he said. "People were shocked out of their minds."

My Wired News article has details.

THERE'S MORE: When are the Democratic presidential candidates going to go after the Bush administration on nuclear security? That's what a former senior Energy Department official wants to know. Recall all the [Republicans] on Capitol Hill beating up Clinton and [then-Energy Secretary] Hazel [O'Leary] for their failures," the official e-mails Defense Tech. "What has changed?"

AND MORE: Rep. Shays notes that nuclear security testing has gotten much harder since 9/11. "The basic assumption used to be, terrorists had to get in and get out [of a place like Y-12]. And getting out was so difficult," he tells Defense Tech. "That's changed since September the 11th. Now, we've got to assume that all they want to do is get in. And that's much more difficult to stop."

AND MORE: At the Pantex nuclear facility, "workers dismantling an aging nuclear weapon secured broken pieces of high explosive by taping them together," according to the AP.

"Homer Simpson has apparently relinquished his post at Springfield nuclear plant," declares the Register.

AND MORE: "Nice story, but 'heads should roll' -- don't make me laugh," says one insider. "If Shays wants to get at the problem, he ought to go down the hall and talk to the labs' protectors over on the Senate side."

AND MORE: What's left of Libya's stillborn nuclear program has just been shipped to Y-12. Oy.