The six-month long Shanghai World Expo will be a challenge for China's nuclear security forces, although the country has a record as one of the most nuclear secure nations of earth, a leading Chinese arms control expert said Tuesday.

Security forces maintained the safety of nuclear facilities during the 2008 Beijing Olympic Games and Paralympic Games, but the duration of the Expo made it a greater risk, said Teng Jianqun, director of research center for arms control with China Institute of International Studies.

"Many people think that nuclear threat is far from them. However, nuclear technology has been widely used in people's daily lives," Teng said in an interview with Xinhua.

"If terrorists used radioactive dirty bombs to attack major events, there would be panic and even chaos," he said.

Teng cited disgraced Pakistani nuclear scientist Dr. Abdul Qadeer Khan, who confessed in 2004 to selling nuclear secrets, as a warning that some scientists and other parties continued to smuggle, trade and produce nuclear materials for profit and other purposes in a global black market.

The illegal trade and proliferation of nuclear materials would create dangerous possibilities for terrorists to launch attacks, he said.

According to statistics from the International Atomic Energy Agency (IAEA), more than 1,500 cases of smuggling and theft of nuclear materials were reported from 1995 to 2008 around the world.

Security cooperation to prevent terrorists from acquiring nuclear materials was a responsibility shouldered by all countries, no matter what attitude they held toward nuclear issues and whether they possessed nuclear facilities or weapons, Teng said.

China had strived for all-round security measures to safeguard nuclear facilities to maintain regional and world peace, and had established nuclear waste disposal plants throughout the nation, he said.

Each of the mainland's 31 provinces, autonomous regions and municipalities had a special facility to store nuclear waste from power stations, hospitals and other places, Teng said.

A large national-level disposal plant was under strict monitoring and supervision to prevent radiation leaks, he said.

The government had promulgated a series of laws and regulations on how civilian organs should transport, utilize and store nuclear materials.

It also reformed the leadership structure of its departments in charge of nuclear issues. Under the Ministry of Environmental Protection, a nuclear security bureau has been set up.

Under the Ministry of Industry and Information Technology, a bureau of national defense science and industry has been established to take over the management of civilian nuclear affairs from the military authority.

"It is fair to say that China has been one of the most successful countries in dealing with nuclear security issues," said Teng.

Chinese President Hu Jintao made a five-point proposal at the Nuclear Security Summit that concluded in Washington last week that all nuclear countries should keep their facilities and materials safe and improve the abilities of developing countries to deal with nuclear security threats.

Teng said Hu's attendance at the summit had been a strong signal of China's commitment to participate in multilateral nuclear cooperation as a permanent member of the UN Security Council and a nuclear country.

The government would build nuclear security demonstration centers in east China to train personnel from developing countries to operate nuclear facilities safely.

"China's major shift to a position that supports nuclear non-proliferation also showcases a positive image in the international community," Teng said.