* Three activists broke through fences at Oak Ridge in July
* Multiple layers of security failed-Inspector General
* Energy Department assessing security at all facilities
WASHINGTON, Aug 31 Guards at a U.S. government plant for storing weapons-grade uranium failed to spot activists, including an 82-year-old nun, who cut through its fences until they walked up to an officer's car and surrendered, an official report said on Friday.
The report from the Energy Department's inspector general, Gregory Friedman, criticized multiple failures of sophisticated security systems and "troubling displays of ineptitude" at the plant in Oak Ridge, Tennessee in July.
Three anti-nuclear activists, including an 82-year-old nun, were not initially spotted or detained as they cut through three perimeter fences on July 28.
They painted slogans and threw what they said was human blood on the outer wall of a building where highly enriched uranium, a key component of nuclear bombs, is stored.
The facility is run by Babcock & Wilcox Co and is responsible for security provided by contractor WSI Oak Ridge, owned by international security firm G4S.
Spokespersons for the contractors did not immediately return calls requesting comment.
The building they vandalized was built after the Sept. 11, 2001 al Qaeda attacks on New York and Washington and had been previously touted as "the Fort Knox of uranium" by a senior government official because of its security features.
Friedman's report said the government had budgeted about $150 million in taxpayer funds for security at the plant for fiscal 2012, yet the officer responding to the alarm did not notice the trespassers until they walked up to his car and "surrendered."
The officer did not draw his weapon nor secure the area, instead letting the trespassers "roam about and retrieve various items from backpacks," the report said.
Another officer hearing alarms did not look outside the building as he was supposed to, and also missed an image of the trespassers on a camera. A third officer turned off the alarm.
Others heard the activists hammering on the building's outside wall, but assumed the sound was from maintenance workers.
"The actions of these officers were inconsistent with the gravity of the situation and existing protocols," Friedman said in the report.
One camera that would have shown the break-in had been broken for about six months, and there was a backlog of repairs needed for security systems at the facility, the report said.
"We found this to be troubling," Friedman said.
Thomas D'Agostino, the administrator of the National Nuclear Security Administration, the Energy Department branch responsible for U.S. nuclear weapons, said changes were underway after the incident.
D'Agostino said staff involved with the incident had been removed, cameras have been fixed, and patrols and training stepped up.
"These steps are just the beginning of the structural and cultural changes that we intend to make," D'Agostino said in a written response included in the report.
The NNSA was also assessing security at all of its facilities, he said, and notified Babcock & Wilcox earlier this month that its contract could be terminated. The company has 30 days to respond to the "show cause" letter.