British regulators on Thursday accepted design plans for a nuclear reactor from French groups Areva and EDF Energy, which are seeking to build a new power station together in southwest England.

The announcement marked the end of a five-year assessment by the Office for Nuclear Regulation (ONR) and the Environment Agency government body to assess the companies' European pressurised water reactor (EPR) for use in Britain.

"We are satisfied that this reactor is suitable for construction in the UK," Colin Patchett, the ONR acting chief inspector of nuclear installations, said in a statement.

"It is a significant step and ensures that this reactor meets the high standards that we insist upon."

However, the regulators have requested 82 design changes to improve the reactor's safety and security, including a number of measures brought in after the Fukushima nuclear disaster in Japan.

There remain site-specific issues that must be addressed before approval of construction on any site, the statement added.

EDF wants to build the first of Britain's new generation of nuclear plants at Hinkley Point in Somerset.

"The acceptance of the design for the EPR reactor is a major achievement and milestone for our new nuclear project in Somerset," said EDF Energy Chief Executive Vincent de Rivaz in a separate statement.

"It represents four years of hard work and allows our project have a stable design before we start, offering a huge boost for the predictability of costs."

EDF is hoping to build four EPRs in Britain -- two at Hinkley and two at Sizewell on the eastern English coast in Suffolk.