Speaking at the Organisation for Economic Cooperation and Development (OECD), Barroso said the treatment of radioactive waste was a major issue of public concern which must be dealt with.
The new law would set standards for waste management that all member states would have to follow.
Moreover, the Commission president said he would start pressing for European safety standards for nuclear plants to become binding worldwide.
Barroso stressed that last June the EU became the first major regional actor to give legal force to the main international nuclear safety standards set by the International Atomic Energy Agency (IAEA).
"Others must now follow suit," he said.
The IAEA's standards, called Fundamental Safety Principles, include the safe construction, operation and decommissioning of nuclear reactors, management of nuclear waste and level of preparedness for radiation incidents.
Efforts to decarbonise electricity production in order to curb global warming have led many European countries to restart their nuclear programmes, which had been phased out due to safety concerns (EurActiv 25/2/09).
While renewable energies are at the heart of climate efforts, nuclear energy also has a role to play, primarily due to its lower cost, Barroso said.
Sarkozy calls for international nuclear financing
In the meantime, French President Nicolas Sarkozy used his speech at the conference to demand funding for the nuclear industry from international development banks.
"I do not understand and I do not accept the shunning of nuclear projects by international financing," Sarkozy reportedly said. "The World Bank, the EBRD [European Bank for Reconstruction and Development] and the other development banks must make a wholehearted commitment to finance such projects," he added.
The French president said he wants to allow nuclear developers to get carbon credits under a post-Kyoto Protocol regime from 2013. The UN's Clean Development Mechanism in its current form does not allow developed countries to gain certified emission reductions (CERs) by funding nuclear projects in the developing world.
Critics said Sarkozy's initiative was aimed at clearing the way for French technology to be sold to other countries. France has one of the world's leading nuclear industries, and generates around 80% of its electricity needs from its 58 reactors.
Over the past few years, France's state-owned nuclear corporation, Areva, has attracted a lot of bad press for delays and major cost overruns in constructing the first model of its European Pressurised Reactor (EPR). The new model has also been plagued by safety concerns, leading critics to warn that the technology should not be exported.
