Security guards at one of the nation's most critical nuclear weapons sites were given the answer key to a "security knowledge test" in the wake of an 82-year-old nun's successful break-in at the Oak Ridge, Tenn., facility, according to the Department of Energy's internal watchdog.

The test was part of a DOE inspection designed to evaluate the guards, who failed to stop Sister Megan Gillespie Rice and two others when they broke through three fences to graffiti the Y-12 National Security Complex. But the site's security contractor -- WSI Oak Ridge -- distributed the test and answers in advance to the employees whose knowledge was to be evaluated.

DOE learned of the test's distribution when an agency inspector saw a copy of the test in a guard's patrol vehicle. The test, which was scheduled for the next day, was postponed and rewritten.

In a report released yesterday, IG Gregory Friedman hints that cheating may be a bigger problem among the nation's nuclear weapons sites.

"In this case, harm was averted by mere happenstance when the compromised testing material was discovered prior to the time the test was actually administered," he wrote. "Based on disclosures by contractor officials, there is also a possibility that compromises of test materials may have occurred at other sites without discovery. Security of the Nation's most sensitive nuclear material storage and processing facilities must not be left to chance."

The report is the latest to sharply criticize the security at Y-12, which is handled by private contractors. A previous IG report determined that the July 28 break-in was successful because of "multiple system failures on several levels" and "troubling displays of ineptitude" in responding to alarms and maintaining critical security equipment.

DOE has since terminated WSI's contract. But Friedman's new report describes weaknesses in how DOE implements the tests meant to ensure that private contractors are adequately guarding the nation's nuclear weapons facilities.

For the Y-12 inspection, DOE emailed a copy of the security knowledge test to the site's management contractor, B&W, because federal officials did not know enough about the site's operations to write the test themselves. B&W officials, in turn, distributed it to WSI, and from there, it made its way through the ranks.

WSI officials used the answer key as a training aid, despite the fact that it was labeled as a test. Though they told IG investigators they did not intend to cheat, Friedman described their testimony as "questionable" and called the failure to safeguard the test "inexplicable and inexcusable."

Indeed, in an email, one WSI official reminded employees of the "sensitivity issue" with the test questions.

"It would not be a good idea for these to be left lying around or for a [security police officer] to have these in hand during an audit," the official wrote.

In a written response to the report, DOE's National Nuclear Security Administration pledged to "ensure that there are no similar lapses" in implementing such tests. But NNSA Administrator Thomas D'Agostino also argued that contractor abuse -- not the agency's release of the test to specific contractor officials -- led to the compromise of the answer key.

Friedman disagreed, pointing to a "fundamental issue" with federal officials' lack of in-depth knowledge of security.

"This issue directly contributed, in our opinion, to the environment that necessitated placing the testing materials in the hands of the contractor in the first place," he wrote.