But, Mr. Barnier, added, “The only point I would make is that it is in Europe’s general interest that Europeans reflect on what are their strategic assets. Each country has its own vision of what is strategically important and I think it would be useful to have more of a common vision or strategy on this question.”

Britain’s energy market is already dominated by European giants, including E.D.F., the French state-controlled power company that is supposed to oversee construction and eventually operate the proposed Hinkley Point project in southwest England, and the German utility E.On. Opening its nuclear power industry to Chinese investment raises questions over Beijing’s influence in a highly sensitive energy sector.

The British government said that any Chinese investments had to meet strict standards for safety and security. Chinese investors will most likely have a minority stake in the Hinkley Point project, the government indicated Thursday, adding that “Over time, stakes in subsequent new power stations could be majority stakes.”

Antony Froggatt, a senior research fellow at Chatham House, a research institute in London, said there were few concerns with a Chinese role because of the partnership with the French in China. “If there were a falling-out politically, I think they would be more likely to withdraw funding than to switch off the lights,” he said.

While Germany wants to shut all of its nuclear plants by 2022 and shift almost entirely to wind and solar power by 2050, Britain is betting big on nuclear power. Though it is also pushing into production of shale oil and gas, Britain aims to cut greenhouse gas emissions in half by the mid-2020s in large part by renewing the older nuclear power plants.