BEIJING, Oct 25 (AP) -- The U.S. government is trying to help China's booming nuclear power industry tighten security with demonstrations this week of measures meant to prevent the theft of radioactive material, an American official said Tuesday.

The event is the first of its kind conducted by the U.S. government anywhere in the world, said Linton Brooks, administrator of the National Nuclear Security Administration, which maintains Washington's nuclear arsenal.

It comes as China's nuclear power industry is on the verge of a huge expansion, with three plants in operation and plans to build 31 more by 2020 as Beijing tries to meet soaring power demands.

The weeklong U.S. demonstrations began Monday in Beijing and include security systems, technology for tracking radioactive material and export controls, all meant to prevent the "theft or diversion" of uranium or plutonium, Brooks said.

"Chinese take security seriously, but you can always benefit from an exchange of technology," Brooks told reporters.

He said the weeklong event was prepared by experts from U.S. nuclear weapons labs at a cost of US$6 million (€4.5 million), and participants include Chinese officials and representatives of power plants.

Brooks wouldn't say whether Washington knows of attempts to steal nuclear material in China. However, he said, "You don't wait until material has been lost and then improve security."

His agency, part of the U.S. Energy Department, also oversees government-run nuclear laboratories and is charged with promoting nuclear security abroad.

Beijing is building nuclear power plants in an effort to ease power shortages while reducing China's dependence on soaring oil imports and use of environmentally damaging coal.

That new emphasis has made this the world's most promising market for U.S., European, Russian and other suppliers of nuclear equipment that have seen opportunities shrink elsewhere.

Foreign firms are awaiting a Chinese decision on contracts for two power plants that could be worth up to US$8 billion (€6 billion) -- the industry's biggest deals in recent years.

Brooks said Chinese officials didn't tell him anything about the status of those contracts, and he said this week's seminar isn't meant to promote sales of American equipment.

"We're interested in providing the best security for nuclear materials anywhere in the world, kind of without regard to whether it has any implication for U.S. commercial interests," he said.

The demonstrations this week included the installation of new security equipment at a Chinese government nuclear institute in Beijing that will be left in place after the event ends, Brooks said. He did not give any details.

Brooks said his agency also is cooperating with several dozen other governments on efforts to tighten nuclear security.

In Russia, the agency has helped to improve security at nuclear facilities and to shut down reactors that produce plutonium, a fuel for weapons, he said.

Elsewhere, the agency is taking part in efforts to tighten export controls and security for radioactive materials that could be used with conventional explosives in a "dirty bomb" that would spread nuclear contamination, Brooks said.