Welsh politicians are being urged by environmental campaigners to say "no" to nuclear power.
Greenpeace members protested to the Prime Minister
Friends of the Earth Cymru has written to all Welsh Assembly Members saying it should be rejected as an energy option because it is unsafe and uneconomic.
The Assembly Government said it did not see a commercial need for nuclear power, but welcomed "an open debate.
Prime Minister Tony Blair has launched an energy review which could pave the way for new nuclear plants.
The Scottish Executive has already made it clear that it would not accept new stations until the issue of waste disposal was solved.
Friends of the Earth Cymru (FoEC) wants a similar declaration from the Welsh Assembly Government.
The WAG has made it clear that it supports the use of renewable energy sources, particularly wind power.
The aim is to increase the amount of energy from renewable sources by 10% over the next five years.
A WAG spokeswoman said it had recently published details of how it would continue to meet the energy needs of Wales "whilst minimising the impact on the environment".
Alternatives to traditional energy generation must be found
She added: "We believe we have identified the right mix of energy sources and with substantial new energy investments coming on stream over the next three to five years we do not see a commercial need for new nuclear energy installations - quite apart from the perennial issues associated with nuclear power i.e. costs, waste and security.
"However we welcome an open debate in this important area."
Gordon James of FoEC said: "Nuclear power has had 50 years to prove itself, but has failed to deliver economic, safe or clean energy and has left a legacy of hazardous waste and financial costs for future generations.
"It is once again being promoted as a quick-fix solution to an energy challenge, but in reality amounts to no more than an expensive fig leaf to cover the embarrassment of failed attempts to make adequate reductions in carbon dioxide emissions."
FoEC argues that, within Wales, nuclear power could not fill the gap left by the closure of Wylfa nuclear power station in five years time.
It claims it would, take at least 10 years to build a new nuclear power station and that the gap could be filled by renewable energy sources.
Alternatives include using onshore and offshore windfarms, wave power and solar power.
The environmental organisation said many other options were also available for filling this gap cost-effectively while reducing emissions of carbon dioxide.
These include new gas-fired power stations and combined heat and power (CHP) systems, which use the heat normally wasted in electricity generation.
Fitting the coal-fired power stations at Aberthaw and Uskmouth with modern technology to reduce carbon dioxide emissions was also an option, it said.