Chinese scientists have begun a new round of tests on the reliability of the experimental thermonuclear fusion reactor, nicknamed "the artificial sun".

The Experimental Advanced Superconducting Tokamak (EAST) fusion reactor, which replicates the energy generating process of the sun, was tested at the Institute of Plasma Physics under the Chinese Academy of Sciences (CAS) in Hefei, capital of east China's Anhui Province.

The reactor was first tested in September 2006. Since then scientists have made adjustments to improve results.

"The new tests show the reactor is very reliable, and we can repeat the experiments," said Wu Songtao, deputy director of the institute.

This new round of tests will continue till Feb. 10.

During the experiment, deuterium and tritium atoms were forced together at a temperature of 100 million degrees Celsius. At that temperature, the super heated plasma, which is neither a gas, a liquid nor a solid, should begin to give off its own energy, scientists explained.

The device is planned to eventually create a plasma lasting 1,000 consecutive seconds, the longest a fusion reactor has ever run.

During the first round of experiments, the reactor created a plasma lasting nearly five seconds and generating an electrical current of 500 kilo amperes.

"With more adjustments to the reactor and more experiments, we will get longer plasma at a higher temperature," Wu said.

The EAST is an upgrade of China's first-generation Tokamak device and the first of its kind in operation in the world, said Chinese scientists.

The Institute of Plasma Physics spent eight years and 200 million yuan (US$25 million) on building the experimental reactor. Compared with similar devices in other countries, EAST cost the least money and time in construction and was the first in operation

Some experts have cast doubt on whether it can produce more energy than it consumes, the main obstacle to making fusion commercially viable.

Wan Yuanxi, general manager of EAST, said it had been proved that the energy input-output ratio of a fusion reactor could reach 1:1.25. With the development of the technology, the ratio was expected to increase to 1:50 in the future.

The main purpose of EAST was to prove that the reactor can produce consecutive and stable plasma, Wan said.

Unlike traditional nuclear fission reactors, which split atoms to create energy and produce dangerous radioactive waste, the EAST uses nuclear fusion to compress atoms at extremely high temperatures to generate energy that would produce very little pollution.

Scientists theorize that a fully functional fusion reactor would provide cheaper, safer, cleaner and endless energy and reduce the world's dependence on fossil fuels.

Minister of Science and Technology Xu Guanhua said earlier that as China was short of energy, global research into energy supply solutions met the strategic interests of the country.

The EAST is part of the International Thermonuclear Experimental Reactor (ITER), which is the largest international program dedicated to experiments in thermonuclear fusion.

In 2003, China joined the 4.6-billion-euro ITER which was originally initiated by the United States and Russia. The first operation of ITER might be in 2016.

Among the six partners involved in this ambitious plan, the European Union will cover 50 percent of the total budget. The remaining five, the United States, Japan, Russia, the Republic of Korea and China, will pay 10 percent each.

"The EAST is the only prototype nearest to the ITER and, thus, it can serve ITER advanced research in terms of engineering technology and physics," said Wan.

But the most optimistic estimation on first commercialization of the ITER said it needs at least half a century.

(Xinhua News Agency January 18, 2007)