CHALK RIVER - Mock terrorist drills are being considered for the nuclear laboratories in Chalk River where a stockpile of highly enriched uranium -- enough for at least one nuclear bomb -- is pitting the benefits of nuclear medicine against the risks of nuclear terrorism.

The Canadian Nuclear Safety Commission is examining the feasibility of staging "force-on-force" security drills at all major Canadian nuclear sites, similar to mandatory drills at key U.S. nuclear facilities in which military units "attack" and test private in-house security forces.

The commission disclosed the idea in response to Citizen questions about renewed and critical attention over the use of highly enriched uranium (HEU) exported from the U.S. to the Chalk River site, two hours northwest of Ottawa, where it is used to make life-saving medical isotopes for Ottawa's MDS Nordion.

As the world's leading medical isotope producer, Nordion's use of HEU is expected to come under renewed scrutiny today in Norway at an international conference of arms control, security and nuclear experts, the latest in a long-running international effort to reduce and eventually eliminate "civilian" HEU commerce.

The meeting follows a major report delivered to the United Nations this month by an independent weapons of mass destruction commission led by Hans Blix, the UN's former chief weapons inspector.

It, too, singled out the need for enhanced security of HEU used for isotope production, though it did not mention specific cases of concern.

An estimated 20 tonnes of civilian HEU is stored around the world, primarily to fuel more than 100 research reactors including four in Canada and dozens in other countries, some with questionable security. Others, like Nordion, use HEU as "target" material in the cores of nuclear reactors to produce medical isotopes.

An estimated 45 kilograms of HEU exported from the U.S. is believed to be stored at Chalk River -- no HEU is kept at Nordion's March Road plant in Kanata -- awaiting the commercial startup of two isotope-producing nuclear reactors intended to maintain Canada's dominance in the $3-billion global molecular imaging and radiotherapeutics market.

Some non-proliferation experts believe the stockpile and Nordion's continued use of HEU presents a tempting target for terrorists conspiring to either steal it to build a weapon of mass destruction or to carry out radiological sabotage at the heavily guarded Chalk River site.

Instead, they say Nordion and Atomic Energy of Canada Ltd., the Crown corporation that owns and operates the facility, should convert their production process to use low-grade uranium (LEU), which is unsuitable for nuclear weapons.

Nordion and AECL characterize a terrorist threat as improbable. The federal nuclear safety commission agrees.

"There is no proliferation risk to the use of this material in Canada," because of the strict national and international regulations and safeguards governing its transport, storage and use, says Aurele Gervais, a commission spokesman.

Even so, commission staff is "reviewing the experience of other countries such as the United States in their FOF (force-on-force) program at nuclear sites to identify key areas that must be considered if such exercises were put in place," he says.

Since the Sept. 11, 2001, terrorist attacks against the U.S., Chalk River and other Canadian nuclear facilities have beefed up security dramatically. AECL now spends about $7 million annually on security measures at Chalk River, including for its own highly trained and heavily armed paramilitary "nuclear response force."

The force routinely conducts joint exercises with various police agencies and, at least once a year, with the military. But based on the commission's statement, the performance testing does not included force-on-force exercises.

The nuclear response force is "formidably trained and armoured to counter the design basis threat and any other potential threats," says Brad Perrin, Chalk River's chief of security. "The effectiveness of the security response is tested regularly and the results are provided," to the nuclear safety commission, but kept classified.

In the U.S., the Department of Energy requires all major nuclear facilities to undergo a mandatory FOF exercise at least once every three years.

The facilities are expected to be able to defend against theft of nuclear materials or radiological sabotage by a few terrorists using surprise and readily available weapons and explosives, as well as against the theft of nuclear secrets.

The results have been revealing.

An eight-month investigation by the independent U.S. Project on Government Oversight found:

* Private security guards contracted to guard facilities housing thousands of tons of HEU and plutonium "lost" against the "attackers" in more than half the exercises.

* In October 2000, during a force-on-force drill at the Los Alamos, New Mexico, nuclear facility, the mock terrorists gained control of sensitive nuclear materials which, if detonated, would have endangered significant parts of New Mexico, Colorado and downwind areas.

* In 1998, the fall of 1999, and again in the spring of 2000, two force-on-force exercises were run to test the Rocky Flats protective force. A "criticality alarm" -- warning that a nuclear chain reaction is potentially imminent -- was set off, creating confusion and allowing the mock terrorists to access to special nuclear materials. The alarm required everyone to immediately leave the building. Hoping to "kill" the "adversaries," the protective force indiscriminately shot employees, controllers and each other as they were exiting the building in response to the alarm.

Even though many deficiencies have been found with the U.S. exercises -- the protective forces, for example, are given at least two hours notice an "attack" is imminent -- the tests are still crucial, says Ed Lyman, senior scientist with the Union of Concerned Scientists global security program. He also is past president of the watchdog U.S. Nuclear Control Institute.

"You can meet every (security) regulation on paper, but when it comes to actually implementing a strategy there could be severe problems. It depends on the size of the (protective) force relative to the attacking force and what you assume about the capabilities of the attacking force.

"A relatively small tweak to the type of strategy that the attackers use could totally overwhelm the defence force. So without performance testing that is realistic ... then I don't take at face value the fact (Chalk River) has some guards with guns running around. The key is force-on-force exercises."

And speculation that nuclear terrorists would have more success attacking poorly guarded nuclear facilities in eastern Europe, for example, is dangerous, he says.

"Obviously the weak links of the chain have to be protected. But the complacent attitude of some of the western facilities is probably a bigger vulnerability than places where there's more attention, like the eastern bloc.

"The fact is that in the West this attitude that 'We're invulnerable,' which obviously Sept. 11 should have shaken up, doesn't seem to have sunk in. We still have HEU at (U.S.) university reactors where there's virtually no security.

"I haven't been to Chalk River. All I know is in a highly defended facility like Oakridge, like Los Alamos, FOF testing demonstrated that there could be a rapid commando attack that could successfully escape with material."

Senior writer Ian MacLeod is national security and terrorism editor.

imacleod@thecitizen.canwest.com