The spread of nuclear weapons is America's greatest national security concern, Secretary of Energy Bill Richardson told a crowd of about 200 in an Institute of Politics speech at the ARCO Forum last night.

"President Clinton says that there is no greater threat than the proliferation of weapons of mass destruction," Richardson said. "The more there are, the more likely they will be used."

Richardson said the impoverishment of Russian scientists who are knowledgeable about nuclear technology is a pressing issue for America and the rest of the world.

"When you have Russian scientists not being paid and having to feed their families...then there is a serious problem," he said. "How many unpaid checks does it take to get these scientists to go to rogue nations who are offering lucrative contracts, such as Iran or Libya, or lately, Belgrade?"

As a result of this situation, the department has taken immediate steps such as the Nuclear Cities Initiatives, Richardson said.

The initiative will close nuclear plants in Russia, give guards watching nuclear weapons food and clothing and grant scientists money for research and development, according to Richardson.

It will also give assistance to prevent catastrophes like Chernobyl, he said.

"There are tens of thousands of scientists who are underemployed or unemployed. We need to help those people," Richardson said.

Over the last five years, Richardson said the U. S. spent $500 million to employ Russian scientists. That was "money that was well spent," he added.

Considering that the amount of plutonium necessary to make a nuclear weapon is only about the size of a fist and costs about $30,000, the spread of nuclear weapons might seem easy, he said.

But Richardson said it is still difficult for rogue nations to purchase the materials they need to build a bomb.

"There's the perception that North Korea or Iraq can just walk in and buy plutonium," Richardson said. "They can't There's a lot of security and intelligence going on there. It's harder than you think."

However, Richard acknowledged that security is sometimes faulty. A recent revelation about an alleged Chinese attempt to steal sensitive information from the nuclear laboratory in Los Alamos, N.M. has put the department under scrutiny.

"I have said this before--security at these labs is lax," he said.

Richardson, who said he has testified before almost 10 congressional committees on this subject, said the department of energy has been working overtime to tighten security at its labs.