President Hu Jintao arrived in Seoul on Sunday to attend the two-day Nuclear Security Summit which will begin on Monday.

Leaders from more than 50 countries and international organizations are expected to review achievements scored since the Washington summit in 2010.

They will discuss cooperative measures to combat the threat of nuclear terrorism, protect nuclear materials and related facilities, and prevent illicit trafficking of nuclear materials, according to the host South Korea.

The leaders will also exchange views on strengthening nuclear safety, which has become the focus of renewed attention following the Fukushima nuclear accident in Japan last year, Xinhua reported.

Chinese diplomats said President Hu will deliver a speech at the summit to elaborate China's position, efforts and important measures regarding nuclear security.

"As a huge country for nuclear energy development, China has always attached great importance to nuclear security and actively participated in international cooperation on nuclear security," Chinese Assistant Foreign Minister Ma Zhaoxu told a press briefing on March 20.

Ma said that China hopes the Seoul summit will improve international consensus, promote international cooperation on nuclear security, enhance global nuclear material and nuclear facilities security, and promote the sustainable development of nuclear energy.

He also expressed China's willingness to actively participate in the discussion of the communique of the Seoul Nuclear Security Summit, which will be the outcome document from the summit.

"The communique will clearly manifest the consensus and resolution of the leaders to enhance international cooperation on nuclear security," he said.

According to the International Atomic Energy Agency (IAEA), from 1993 to 2011, more than 2,100 incidents of nuclear and radioactive materials were confirmed, of which about 400 incidents involved unauthorized possession, movement or attempts to illegally trade or use nuclear and radioactive materials.

Khammar Mrabit, director of the IAEA's Office of Nuclear Security, said at a press briefing last week that more needs to be done to improve the safety of nuclear and radioactive materials worldwide.

"Nuclear and other radioactive materials are still not properly secured. We have roughly around 200 incidents per year," he said, adding that "continuous improvement is a must. Complacency is bad."

The Seoul summit is a follow-up of the first summit in Washington in April 2010, at which leaders from 47 states and three international organizations discussed plans to strengthen nuclear security by preventing the misuse of nuclear materials by non-state actors.

President Hu attended the Washington summit and delivered a speech entitled "Join hands to meet nuclear security challenges and promote peace and development."

On the sidelines of the Seoul summit, Hu is expected to meet some other leaders to discuss bilateral ties and issues of mutual concern.

Hu will also travel to New Delhi for a meeting of the BRICS, which groups Brazil, Russia, India, China and South Africa.

After that, the Chinese leader will pay a state visit to Cambodia.