At a nuclear waste site in Normandy, robotic arms guided by technicians behind a protective shield maneuver a pipe that will turn radioactive chemicals into glass as France seeks to make safe the byproducts of its growing reliance on atomic power.
The fuel-cooling pools in La Hague, on the country's northwestern tip, could be full by the end of the decade and state-owned Orano, which runs them, says the government needs to outline a long-term strategy to modernize its aging facilities no later than 2025.
While more nuclear energy can help France and other countries to reduce planet-warming emissions, environmental campaigners say it replaces one problem with another.
To seek solutions, President Emmanuel Macron, who has announced plans to build at least six new reactors by 2050, on Friday chairs the first of a series of meetings on nuclear policy that will discuss investments and waste recycling.
"We can't have a responsible nuclear policy without taking into account the handling of used fuel and waste. It's a subject we can't sweep under the rug," a government adviser told Reuters, speaking on condition of anonymity.
"We have real skills and a real technological advantage, especially over the United States. Russia is the only other country that is able to do what France does in terms of treatment and recycling."
La Hague is the country's sole site able to process and partially recycle used nuclear fuel.
France historically has relied on nuclear power for around 70% of its energy, although the share is likely to have fallen last year as the nuclear fleet suffered repeated outages.
Since the launch of the site at La Hague in 1976, it has treated nearly 40,000 tons of radioactive material and recycled some into nuclear fuel that can be reused. The waste that cannot be recycled is mixed with hardening slices of glass and buried for short-term storage underground.
But its four existing cooling pools for spent fuel rods and recycled fuel that has been reused risk saturation by 2030, according to French power giant EDF, which runs France's 56-strong fleet of reactors, the world's second biggest after the United States.
Should saturation happen, France's reactors would have nowhere to place their spent fuel and would have to shut down -- a worst-case scenario that led France's Court of Audit to designate La Hague as "an important vulnerability point" in 2019.
Cool pools and deep clay
EDF is hurrying to build an extra refrigerated pool at La Hague, at a cost of $1.37 billion, to store spent nuclear fuel -- a first step before the waste can be treated -- but that will not be ready until 2034 at the earliest.
Meanwhile, France's national agency for managing nuclear waste last month requested approval for a project to store permanently high-level radioactive waste.
The plan, called Cigéo, would involve placing the waste 500 meters below ground in a clay formation in eastern France.
Construction is expected in 2027 if it gets approval. Among those opposed to it are residents of the nearby village of Bure and anti-nuclear campaigners.
Jean-Christophe Varin, deputy director of the La Hague site, told Reuters Orano could be flexible to ensure more recycling is done at the facility and there were "several possible scenarios."
However, he said they could not be worked on in detail in the absence of a strategic vision. Orano, for which EDF accounts for 95% of its recycling business, says it needs clear direction from the government no later than 2025, to give it time to plan the necessary investments.
The costs are likely to be high. Just keeping up with current operations at La Hague costs nearly $330 million a year.
Options EDF and Orano are considering include finding a way to recycle the used fuel more than once, but critics say the recycling itself creates more radioactive waste and is not a long-term solution. For now, the backup plan is to fit more fuel containers into the existing pools.
After being cooled in a pool for about seven years, used nuclear fuel is separated into non-recyclable leftovers that are turned into glass (4% of the material), plutonium (1%) to create a new nuclear fuel called MOX, on which around 40% of France's reactors can run, and reprocessed uranium (95%).
The uranium in the past was sent to Russia for reenrichment and return for use in some EDF reactors, but EDF stopped doing that in 2013 as it was too costly.
In spite of the war in Ukraine, which has made many in the West avoid doing business with Russia, EDF is expected to resume sending uranium to Russia this year as the only country able to process it. It declined to confirm to Reuters it would do so.
The facility at La Hague, with its 1980s-era buildings and Star Wars-style control rooms, has its limitations.
"If we had to process MOX fuel in large quantities, the facility today isn't adapted for it," Varin said. "For multicycle recycling, the technology is not the same, so the modernization or replacement of installations" would require "significant" investments, he said.