Opponents of nuclear power have seized on an initial report which indicates that a solution to managing radioactive waste may be some way off.
The disposal of nuclear waste is a long-term problem
The Committee on Radioactive Waste Management's final report will help the UK Government decide whether or not to support new nuclear power stations.
The Scottish Green Party said the warning shows the scale of the problem.
The Scottish Executive said there would be no more nuclear power stations until the waste issue has been resolved.
The Committee on Radioactive Waste Management is due to deliver its conclusions in July.
However, the draft of its initial report states: "If ministers accept our recommendations, the UK's nuclear waste problem is not solved.
"Having a strategy is a start. The real challenge follows."
It is not clear whether this was a reference to the difficulty of siting a nuclear waste dump.
However, the Greens have interpreted this as an admission that the problem cannot be resolved.
First Minister Jack McConnell has pledged that the executive would not be prepared to consider progressing with nuclear power until the problem of nuclear waste was resolved.
He said last year: "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.
"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."
Options for disposal being considered by the committee are deep disposal, phased deep disposal where the waste is retrievable, shallow burial of short-lived waste and interim storage as a temporary management solution.
BBC Scotland environment correspondent Louise Batchelor said: "Once the committee makes its recommendation, even supposing the government accept it and supposing it's for deep disposal, there's still the huge problem of public acceptability, finding a place to actually put it, going through the planning process and so on.
"It all depends on what First Minister Jack McConnell and the executive accept as a solution."
Green MSP Chris Ballance said: "The admission in this document reveals that Jack McConnell will never be able to justify a new nuclear reactor this side of the May 2007 election, and it exposes the arrant nonsense that proposals to manage the nuclear waste legacy could possibly be described as 'solving' the problem.
"On top of the costs, dangers, risks and a failure to truly tackle climate change - nuclear power creates waste that is not going to be magicked away by the CoRWM report."
Scottish National Party energy spokesman Richard Lochhead said: "No solution for dealing with nuclear waste means no more nuclear for Scotland.
"Nuclear power is dirty, dangerous and unwanted in Scotland, and this report only shows that our objections to nuclear power are totally justified."