The International Atomic Energy Agency, looking back on half a century of the non-military use of nuclear power, says, with the end of the cold war, the world is less susceptible nuclear dangers, such as those posed by the dangerous power plants, but faces a greater threat from internal sabotage.

Fifty years ago Saturday, a nuclear plant went on stream in the town of Obninsk, near Moscow providing power to around 2,000 homes. Although nuclear energy fission was first discovered in 1939 and nuclear weapons tested in 1945, this Soviet reactor was the first used for civilian nuclear power.

IAEA chief, Mohamed ElBaradei, is meeting with Russian President Putin Saturday, in Moscow to mark the occasion and reflect on the past and future of nuclear power.

Accompanying him is Ken Brockman, head of nuclear safety at the IAEA in Vienna.

Mr. Brockman told VOA before he left for Moscow that the fall of Communism meant scientists could communicate across borders more quickly to prevent a second Chernobyl, the worst nuclear accident that occurred in 1986.

"The openness and communications now allows through the entire world both within the Russian Federation and in all of the nation states that have come back after the break up of the Soviet, there's much open communications and we are able to share lessons learnt in the United States are fully integrated in programs in Eastern Europe," he said. "If something happens in an eastern European reactor that information gets back to the U.S., Canada and the U.K and they can look at the implications there."

But Mr. Brockman says, since the terror attacks on New York City and Washington in September 2001, his division has focussed on security aspects and anti-terrorism.

Bulgarian Foreign Minister, Solomon Passy, told reporters this week in Vienna that his country has to shut down nuclear reactors by 2007 before joining the European Union, which poses a potential security problem.

"Therefore we shall have to release several thousand excellent nuclear specialists, professionals and Bulgaria will have to release them from active duty; they are private citizens and they might easily be attracted by countries, or governments or forces that are not under the control of the international community and this is a serious threat that all of us will have to address," said Solomon Passy.

The Bulgarian diplomat is head of the Organization for Security and Cooperation in Europe and is working closely with the IAEA on counterterrorism.

But Mr. Brockman thinks unemployed atomic scientists will find jobs because new reactors are under construction in Asia. Still, he says, the security of nuclear power plants is a major concern.

"There are many different types of scenarios you could look at from the physical protection of the plant which is where I'd put your airplane thing into and also making sure the plants are appropriately safeguarded against sabotage," he said.

The IAEA says there are 450 nuclear power plants in 30 countries, generating about one sixth of the world's electricity supply.