The type of reactor EDF wants to build at Hinkley hasn't yet been shown to work.
This type of reactor has not been built because an accelerator with sufficient power does not exist, Dr. Raja said.
This special type of reactor is designed to extend the nuclear fuel supply for electric power generation.
In this type of reactor, the boiling-water variety, it's easier for an operator to regulate the output of power.
This type of reactor, too small for electricity and larger than needed for research, is now providing the fuel for atomic weapons programs in India, Israel and Pakistan.
"This type of reactor requires a large supply of uranium fuel," they added, saying that it "raises questions about when this reactor could have operated".
Areva and Mistubishi Heavy have rival designs of their own, but have also set up a joint venture to promote yet another type of reactor.
A by-product of this type of reactor is plutonium which, like enriched uranium, can be used to make nuclear weapons.
Mr. Wallace is the chairman of UniStar Nuclear Energy, a partnership of Constellation Energy and the French national utility, Électricité de France, which is building a new type of reactor in Flamanville, France.
That is the ceramic that nuclear engineers use for the "pebble bed" type of reactor: the ceramic wraps around the fuel so that it cannot get hot enough to melt, and the ceramic will not burn.
SHIDAO, China — While engineers at Japan's stricken nuclear power plant struggle to keep its uranium fuel rods from melting down, engineers in China are building a radically different type of reactor that some experts say offers a safer nuclear alternative.
