The companies have additional work to complete before they can get the final approval, but the regulator said it was satisfied the companies have credible ways of resolving the outstanding issues.
The approval ends four years of work assessing the reactor designs. It also gives nuclear developers confidence that the two reactor designs--Areva's EPR and Westinghouse's AP1000--are suitable for use in the U.K.
"This is very good news for the EPR and for U.K. new nuclear build," said Vincent de Rivaz, chief executive of Electricite de France SA's U.K. unit.
EDF is spearheading the U.K.'s nuclear revival with plans to build a new nuclear power station, using Areva EPR reactors, at Hinkley Point in Somerset in southwest England.
"This announcement marks a tremendous milestone on the road towards seeing AP1000 reactors built in the U.K.," said Mike Tynan, U.K., Middle East & Egypt vice president for Westinghouse, a unit of Toshiba Corp.
Tynan added that remaining issues will be resolved once the company's reactor is selected by a U.K. utility customer.
The interim design acceptance confirms that all the plans on how the industry will resolve the outstanding issues are in place. This includes how the companies will address matters raised in the chief nuclear inspector's report published in October on lessons to be learnt for the U.K. from the Fukushima nuclear disaster, the regulator said.
A final design acceptance certificate will be issued when the work is completed, the regulator said, adding that neither reactor can be built in the U.K. until then.
Any prospective operator of a new nuclear power station also needs to apply for and be granted a nuclear site license as well as other permits and planning consents before the power plants can be built.
Horizon Nuclear Power, a joint-venture between German utilities E.ON AG and RWE AG with plans to build new nuclear reactors in the U.K., welcomed the interim approval and said it was in the final stages of selecting a reactor technology.
By Selina Williams
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