Many operators have begun programs, or expressed an intention, to run reactors beyond their planned design lifetimes, said the International Atomic Energy Agency (IAEA) document which has not yet been made public.
“There are growing expectations that older nuclear reactors should meet enhanced safety objectives, closer to that of recent or future reactor designs,” the IAEA’s annual Nuclear Safety Review said.
“There is a concern about the ability of the ageing nuclear fleet to fulfill these expectations.”
The Fukushima tragedy was triggered on 11 March 11 2011, when an earthquake unleashed a tsunami that left 19,000 people dead or missing. It also smashed into the coastal power plant causing a series of catastrophic failures at the facility.
Public confidence shaken
Images of the stricken plant shook public confidence in nuclear power and forced the nuclear industry to launch a campaign to defend its safety record.
IAEA Director General Yukiya Amano said last week that nuclear power is now safer than it was a year ago. The report said the "operational level of NPP (nuclear power plant) safety around the world remains high".
It cited steady improvements in terms of unplanned reactor shutdowns in recent years.
But the 56-page IAEA document also highlighted an ageing nuclear fleet, with 80% of the 435 facilities more than two decades old at the end of last year.
This “could impact safety and their ability to meet member states' energy requirements in an economical and efficient manner”, said the report, which has been submitted to IAEA member states for approval.
Operators and regulators opting for so-called long term operation “must thoroughly analyse the safety aspects related to the ageing of 'irreplaceable' key components”, it added.
About 70% of the world's 254 research reactors have been in operation for over 30 years “with many of them exceeding their original design life,” it said.
Despite the disaster in Fukushima, states such as China and India continue to look to nuclear energy to meet their growing energy needs, the IAEA report said, adding that some “are even accelerating their nuclear energy programmes”.
France is building its first ‘advanced’ reactor and Russia is seeking to double its nuclear energy output by 2020, it said.