The UN atomic agency on Wednesday praised Britain's improvements to its regulatory framework for nuclear safety but said more needed to be done.

Following a 10-day visit, the International Atomic Energy Agency (IAEA) said in preliminary findings Britain had made "considerable progress since reviews in 2006 and 2009".

"Recommendations and suggestions" were however made, "aimed at strengthening the effectiveness of the country's regulatory framework and functions in line with IAEA Safety Standards, the control of radioactive discharges and environmental monitoring".

Britain has 16 operating nuclear power reactors at nine sites, producing some 16 percent of its electricity, and 27 units either in permanent shutdown or being decommissioned.

A final report will be published in three months, the IAEA said.