NUCLEAR bosses have welcomed decisions to provisionally approve the design of a new generation of UK reactors, including at Sizewell C.

The Office of Nuclear Regulation (ONR) has said it is satisfied with the new EPR Pressurised Water Reactor while the Environment Agency has also given approval, subject to conditions, including proving that lessons had been learnt from the Fukushima nuclear disaster in Japan.

EDF, which owns Sizewell B and is in the process of developing plans for two further EPR reactors at the site, said the approval represented a “major step forward” for the construction of new nuclear plants.

The ONR has now issued an Interim Design Acceptance Confirmation, and the Environment Agency has issued an Interim Statement of Design Acceptability for the reactors.

Vincent de Rivaz, EDF Energy chief executive, said: “This is very good news for the EPR and for UK new nuclear build.

“It is a major milestone which follows a detailed four-year review by one of the most rigorous independent nuclear safety authorities in the world.

“We are conscious that there is still a lot to do to achieve final certification, and we will do it.”

Kevin Allars, ONR director for nuclear new build, said: “This interim acceptance confirms that all the plans on how the industry will resolve the outstanding issues are in place. This includes how they will address matters raised in the chief nuclear inspector’s report, published in October, on lessons learnt for the UK from Fukushima. It is for the designers now to satisfy us that they have resolved these issues. We will not allow industry to build the reactors until they have done so.”

Joe McHugh, the Environment Agency head of nuclear regulation, said: “The assessment has been a challenging process involving more than 60 expert engineers, scientists and regulators but one that has enabled us to identify issues early on. It means we are far better placed to ensure that any new reactors that are built in the UK meet high standards of safety, security and environmental protection.”

EDF is currently at an advanced stage of planning for a new twin-EPR development at Hinkley Point, Somerset, and hopes to begin public consulation on a new development at Sizewell next year. Construction work on the Sizewell project could begin in 2015, if approved.