France's nuclear safety watchdog said the site, near Soulaine in the heart of Champagne, could re-open after its operator had fixed a damaged wall helping to contain radioactive waste.
The move has aroused concern from winemakers and campaigns groups. They say the Soulaine site, set to be one of the world's biggest nuclear waste dumps when full, poses too much of a risk to one of France's iconic wine areas.
The wall at Soulaine cracked last year under the pressure of concrete piled on top of the nuclear waste. "This revealed a flaw in the conception of the storage cells of the site," France's safety watchdog said in a statement.
It warned more building work was needed on similar sites to prevent the same problem happening again.
Environmental campaigns group Greenpeace said the safety agency's statement showed the Soulaine site, and others like it, were not safe.
The group said independent tests done by the ACRO laboratory in France's Normandy region, had revealed a leak from a similar nuclear waste dump there.
The testing found levels of radioactivity in underground water used by dairy farmers more than seven times above the European safety limit. Radioactivity was up to 90 times above the safety limit on agricultural land closer to the waste site, Greenpeace claimed.
The source of the high radioactivity levels is thought to be a form of radioactive waste called tritium. The nuclear waste site at Soulaine in Champagne is expected to contain three times more tritium than its counterpart in Normandy.
That has some winemakers concerned.
"No winemaker agrees with a site like that next to the vines," said Alain Reaut, who makes organic Champagne in the Aube area, around 50km from the Soulaine site.
Reaut, who owns 11 hectares of vines, criticised the secrecy of the company responsible for the waste dump, ANDRA. "I have not heard about any problem, they should say what is going on. It suits them to say nothing but it could be a catastrophe for us."
Fred Marillier, of Greenpeace France, said Champagne makers should act before it is too late. "The Champagne producers are facing two nuclear time bombs - one already leaking at Soulaine, and one planned at Bure."
Concerned winemakers in France's Rhône area previously persuaded the government to drop plans for a nuclear waste site near their vines, due to contamination fears.
ANDRA, which deals with most of France's nuclear waste, has repeatedly stated that its sites followed strict safety procedures and there was no cause for concern.
France's problem is that nuclear power provides more than three quarters of its energy, a policy that has cut reliance on other countries, but created a mountain of radioactive waste.
The French Senate will next month vote on new laws for managing radioactive waste in the country, indicating the government is attempting to tackle concerns but has no plans to abandon its long-standing commitment to nuclear energy.