The first minister has said he is keeping his "options open" on the question of new nuclear power stations.
Two nuclear power stations in Scotland are near the end of their lives
But Jack McConnell repeated that the Scottish Executive was not prepared to consider the issue until the problem of nuclear waste was resolved.
He told a media briefing that the executive would use its powers "in the best interests of Scotland".
Opposition parties said ministers should rule out nuclear and focus their attention on renewable energy.
Mr McConnell's comments came after Trade Secretary Alan Johnson said he has not yet decided if the UK should be building a new generation of nuclear power stations.
In May, Mr McConnell said that the Scottish Executive had the power to stop nuclear power stations being built north of the border, regardless of Westminster's decision.
The first minister also said that there would be no new plants in Scotland until the issue of managing radioactive waste was resolved.
He repeated that stance last month during a BBC Scotland News Interactive webcast.
"Until there's a solution to the problem of nuclear waste, I don't believe that we should be involved in further generation of nuclear power," he said.
"The solving of the issue of nuclear waste seems to me to be of paramount importance because that waste currently exists and needs to be dealt with."
On Monday, the issue was raised at Mr McConnell's first media briefing since the summer.
He said: "We are not prepared to consider a new nuclear power station in Scotland until the issue of waste is successfully resolved.
"And even then it will only be to consider, discuss and debate. It will not necessarily be to agree."
'Out of touch'
But he added: "I think it's right and proper that in the longer term we keep energy options open."
Scottish National Party energy spokesman Richard Lochhead claimed that Mr McConnell was out of touch with public opinion.
"We should be trying to create a better and safer future for Scotland by making the most of Scotland's vast renewable energy potential, instead we see the first minister willing to jeopardise public safety to keep London happy," he said.
"Rather than spend billions on unwanted and potentially dangerous new nuclear power stations, Scotland should invest in developing our offshore renewable potential and carbon capture technology.
"The first minister should rule out new nuclear power stations once and for all and throw his weight behind turning Scotland into a renewable powerhouse instead of a nuclear danger zone."
The Scottish Green Party's spokesman on nuclear power, Chris Ballance, said: "It certainly appears as if Mr McConnell is biding his time before he presses the nuclear button.
"A mature debate on nuclear power would need to consider a lot more than just where to dump the waste - it would need to look at the risks, the costs, the fuel sourcing, the links to weapons of mass destruction and also the fact that nuclear power still adds to climate change pollution."