Radioactive waste from Europe’s nuclear reactors must in future be buried in secure bunkers, the EU has agreed.
The new rules force national nuclear authorities to draw up disposal plans by 2015, which will be vetted by Europe's energy commissioner Guenther Oettinger.
"After years of inaction, the EU for the very first time commits itself to a final disposal of nuclear waste," Oettinger said in a statement.
The 14 European Union member states using nuclear power currently store the radioactive waste in surface bunkers or warehouses for decades while it cools down. But crises such as Russia's wildfires last summer and leakage at Japan's stricken Fukushima plant have highlighted the risks posed by surface storage.
Nuclear energy has not been popular in Europe since the 1986 Chernobyl disaster, but it is even less so since Fukushima, and Germany has even agreed to phase out nuclear power completely by 2022.
Oettinger has made nuclear safety one of the main issues of his five-year tenure, pushing ministers to develop a pan-European safety strategy for the first time.
The first step in that strategy is a series of "stress tests" on nuclear plants, which started in June. The second is the decision to dispose of spent nuclear fuel in secure repositories.
Oettinger's team, which will vet the national strategies, has already stated its preference for "deep geological repositories" - caverns to be built in clay or granite rocks between 100 and 700 metres underground.
"National programmes have to include plans with a concrete timetable for the construction of disposal facilities," they said in a statement.
Safety standards drawn up by the International Atomic Energy Agency will also become legally binding as part of the plan.
Oettinger had initially proposed a total ban on exports of radioactive waste to other countries for reprocessing, but ministers created a loophole for future exports. Instead, waste can be shipped to countries that already have deep geological storage.
"At present, such deep geological repositories do not exist anywhere in the world nor is a repository in construction outside of the EU," said Oettinger's team. "It takes currently a minimum of 40 years to develop and build one."
The EU's 143 nuclear plants produce about 50,000 cubic metres of radioactive waste each year, says nuclear industry body Foratom. About 15 per cent of that is high level waste.