The world has yet to experience an act of nuclear terrorism. High-level discussions this week in Washington will resolve to keep things that way as fresh attacks in Brussels loom over the talks.

Leaders from more than 50 countries, including Canadian Prime Minister Justin Trudeau, meet Thursday and Friday in the U.S. capital for the fourth and final Nuclear Security Summit, a conference dedicated to ensuring the most devastating weapons remain out of the reach of would-be attackers.

The summit, an initiative led by U.S. President Barack Obama, confronts the growing menace of ISIS and how best to address nuclear smuggling and transnational intelligence-sharing.

It will take place against an alarming backdrop.

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Canadian Prime Minister Justin Trudeau will be among the leaders and dignitaries representing more than 50 countries attending the two-day Nuclear Security Summit in Washington, D.C. (Sean Kilpatrick/Canadian Press)

Security analysts fear that ISIS has been seeking radioactive material to build a "dirty bomb," noting that iridium capsules were stolen from a storage facility in Basra, Iraq, in February.

At least four groups, including Al-Qaeda and the Japanese doomsday cult Aum Shinyriko, have for years harboured nuclear ambitions, according to reports.

And just days after the massacre that killed 130 people in Paris last November, Belgian authorities made an eye-opening find: Evidence of spying on a top nuclear official in Belgium by a suspected Islamic State conspirator.

"What we know is that an ISIS associate had this footage seized from a videotape showing the comings and goings of a nuclear scientist and his family," said Carl Robichaud, an expert in strengthening nuclear security with the Carnegie Corporation of New York. "That suggests that there was an interest in nuclear and radiological material."

International fears

The surveillance video was found in the home of Mohamed Bakkali, who was arrested following the attacks in Paris and linked to the killers.

"Some have speculated this was about planning a kidnapping," Robichaud said.

Fears about attackers building nuclear weapons weigh heavily on the international community. Acquiring the weapons-grade fissile material — highly enriched uranium — would make that possible, government experts said at a nuclear summit briefing this week in Washington.


Screens overhead display U.S. President Barack Obama as he speaks at the closing session of the Nuclear Security Summit in The Hague in March 2014. The 2016 summit, to be held on Thursday and Friday in Washington, opens just days after ISIS claimed responsibility for attacks in Belgium. (Frank Augstein/Reuters)

Although it's unclear how real the threat of nuclear terrorism is, they believe the horrific scale of a prospective nuclear terrorism plot is enough to warrant the summit.

"A terrorist attack with an improvised nuclear device would create political, economic, social, psychological and environmental havoc around the world, no matter where the attack occurs," Laura Holgate, a White House director who oversees programs for reducing nuclear and biological weapons, told reporters on Tuesday.

The 2014 nuclear summit, held in The Hague, included a simulation asking world leaders to respond to a fictitious scenario involving the release of radiological materials. A similar exercise is expected this year.

Rose Gottemoeller, an adviser on arms control with the U.S. State Department, noted that nuclear-reduction talks have resulted in a 50 per cent reduction in the number of countries holding highly enriched uranium or separated plutonium.

Since 2009, countries participating in the summit have eliminated enough nuclear material for 1,500 nuclear weapons.

But some world nuclear powers will be conspicuously absent from the table this week. The Russian government will be boycotting the talks, and Pakistani Prime Minister Nawaz Sharif cancelled his visit following the Easter Sunday suicide bombing that targeted Christians in Lahore.

Security boosted

Belgian authorities have stepped up security, posting armed guards at the country's nuclear facilities in the wake of attacks this month in Brussels that killed 35 people and wounded more than 300.

A 2014 scare in Belgium involved suspected sabotage of a reactor. Though terrorism was not believed to be the cause, the incident underscored the vulnerability of the facilities.

Obama made confronting the dangers of nuclear war a key theme in a 2009 address in Prague, stating that "as the only nuclear power to have used a nuclear weapon, the United States has a moral responsibility to act" on leading discussions on global disarmament.

The Nuclear Security Summit was borne out of that speech.

But Paul Meyer, a former Canadian disarmament ambassador with the Simons Foundation, a non-profit dedicated to scientific research, views the resulting summit as a disappointment, given the promise of Obama's speech.

"It represents a drastic drop in the level of ambition regarding doing something towards real nuclear security," he said, questioning whether "making higher fences around nuclear storage facilities" goes far enough towards keeping the world secure.

Without non-proliferation as a key part of the agenda, he said, "it's like having 50 of the greatest virtuoso pianists across the world coming to the White House to play Chopsticks."

Meyer wants more discussion about disarmament.

Canada, for its part, is well-placed to be an active participant in the gathering, having shown "impeccable credentials" in terms of early rejection of nuclear weapons status, Meyer said.

Securing materials

Although Canadian activists have pressured Trudeau to make non-proliferation and disarmament priorities when he attends the Nuclear Security Summit, the conference focuses on securing valuable nuclear materials, particularly those in the civilian space.

Canada has made a concerted push to renew nuclear non-proliferation efforts, starting with efforts to hammer out a Fissile Material Cut-off Treaty, a proposal that would rid the world of the materials that can be used to make nuclear weapons.

"We must take the necessary steps to enhance our collective security so that Canadians and others around the world can feel safe and free in their communities," Trudeau said in a statement before Thursday's summit.

Canada scores well — ranking third overall out of 24 countries — on the Nuclear Threat Initiative's Nuclear Security Index "theft ranking," a measure that takes into account security measures to protect weapons-usable nuclear materials.

Nine countries around the world are believed by security experts to have nuclear weapons: the United States, Russia, the United Kingdom, France, China, Pakistan, India, North Korea and Israel.