TEHRAN, Iran — Iran's nuclear agency began studies Saturday to build an experimental nuclear fusion reactor, something that has yet to be achieved by any nation.

Iran is not known to have carried out anything but basic fusion research, but it does have a nuclear fission program that the U.S. and its allies believe is a front to build weapons -- a charge Tehran denies.

Nuclear fusion, the process powering the sun and stars, has so far only been mastered as a weapon, producing the thermonuclear explosions of hydrogen bombs. It has never been harnessed for power generation.

Vice President Ali Akbar Salehi, who also heads the Atomic Energy Organization of Iran, told a conference on the new research program that his agency has set an initial budget of $8 million to conduct "serious" research in the area of nuclear fusion.

Asghar Sediqzadeh, the head of the new fusion research center said Iran will take two years to complete these studies and then another decade to design and build a reactor.

"The scientific phase of the project effectively began today. We have already hired 50 experts for this purpose," he told state TV.

The United States, the European Union, China, India, Russia, Japan and South Korea signed an accord in 2006 to build a $12.8 billion experimental fusion reactor at Cadarache, southern France, aimed at revolutionizing global energy use for future generations.

The International Thermonuclear Experimental Reactor, or ITER, members have said no single country can afford the immense investment needed to move the science forward.

Salehi, Iran's nuclear chief, said Iran was willing to join any international grouping to offer its expertise to promote the project. However, he said Iran will go its own way should the world not welcome it.

"We are ready to enter into cooperation with any international group or country," he told the semiofficial ISNA news agency.

Salehi said it would take 20 to 30 years before nuclear fusion energy can be commercialized but that Iran seeks to make use of all the capacity inside Iran to speed up its research.

The UN Security Council has already passed four sets of sanctions over Iran's nuclear program on suspicions it is being used to produce weapons. Iran denies the accusations, saying its program is geared merely toward generating electricity.