Nuclear reactors are not being built rapidly enough around the world to meet targets on curbing global warming, a report by the World Nuclear Association, an industry body, said on Tuesday.
The association, which represents the global nuclear industry, says 1,000 gigawatts of new nuclear capacity needs to be added by 2050 so nuclear can supply around 25 percent of global electricity.
Last year, more nuclear reactors were under construction and came online than at any other time in the past 25 years and building times have improved.
However, the rate of new grid connections will have to increase significantly to provide enough clean energy to meet globally agreed climate change targets.
In December last year, countries agreed to limit the global average temperature rise to less than 2 degrees Celsius above pre-industrial levels and to pursue efforts towards a 1.5 degree limit.
However, greenhouse gas emissions continue to rise and a 2 degree limit would require the almost total decarbonisation of the world's energy supply.
"The rate of nuclear new build is insufficient if the world is to meet the targets for reducing the impacts of global warming...," the report said.
The global nuclear industry continues to face challenges.
There are issues around the public acceptance of nuclear energy in some European countries; tough economic conditions for operators in parts of the United States and Europe where power prices have fallen due to a growing share of renewable sources and Japan has permanently closed six reactors which had been offline since the Fukushima accident in 2011, the report said.
At the end of 2015 there were 66 civil power reactors under construction around the world and another 158 planned. The average construction time of a new reactor in 2015 was 73 months, compared to an average 82.5 months for all civil nuclear reactors built over the past 60 years, according to the report.