Fan Jishe, a researcher of US strategies at the Chinese Academy of Social Sciences, said China's nuclear security record has set an example for the world.

Liu Wei, general manager of China Nuclear Power Engineering Co, said, "Chinese nuclear technologies can meet the highest standards of international safety requirements."

Wang Yiren, deputy head of the China Atomic Energy Authority, said this week that in the past six decades China has never lost "one gram or one piece" of important nuclear material.

China has worked with the International Atomic Energy Agency to train more than 1,000 nuclear security professionals from around the world, he added.

A nuclear security center jointly built by China and the United States — the biggest and most advanced one worldwide — began operating on March 18 in Beijing.

Ruan Zongze, vice-president of the China Institute of International Studies, said although so far no nuclear terror attacks have happened, countries have "to be extremely careful".

"You can never do too much in the fight against nuclear terrorism."

The summit, a biennial event initiated by US President Barack Obama, will this year draw together leaders and envoys from 52 countries and four international organizations.

Lu Haoting contributed to this story.