"The idea is to be very low cost, very safe and generate very little waste," said the billionaire during a talk at China's Ministry of Science and Technology.

Gates has largely funded a Washington state-based company, TerraPower, that is developing a Generation IV nuclear reactor that can run on depleted uranium.

The general manager of state-owned China National Nuclear Corporation, Sun Qin, was quoted in Chinese media last week saying Gates was working with it to research and develop a reactor.

"TerraPower is having very good discussions with CNNC and various people in the Chinese government," said Gates, cautioning that they were at an early stage.

Gates says perhaps as much as a billion dollars will be put into research and development over the next five years.

TerraPower says its traveling wave reactor would run for decades on depleted uranium and produce significantly smaller amounts of nuclear waste than conventional reactors.

"All these new designs are going to be incredibly safe," Gates told the audience. "They require no human action to remain safe at all times."

He said they also benefit from an ability to simulate earthquake and tidal wave conditions. "It takes safety to a new level," he said.

Since leaving Microsoft Corp., Gates has concentrated on philanthropy and advocating on public health, education and clean energy issues.

Gates was at the Ministry of Science and Technology to talk about a joint project between China and the Bill & Melinda Gates Foundation to support innovative research and development to help alleviate poverty.

Gates said the ministry will help identify entrepreneurs and companies to manufacture new products in global health and agriculture to "change the lives of poor people," including new vaccines and diagnostics and genetically modified seeds.

"China has a lot to contribute because it's solved many of the problems of poverty, not all of them but a lot of them, itself, and many Asian, south Asian and African countries are well behind, whether it's agriculture or health," said Gates.