nuclear bomb designer Tuck gave a talk in Auckland a quarter-century
ago, he deemed the disposal of high-level nuclear waste
"trivial". He failed to state what the solution would
be, and I have always remembered his remark as one of the wildest I've
truly wonky 'solutions' have been proposed by respectable experts.
For instance, the USA govt for a period envisaged, among other
options, placing metal canisters of high-level waste on the Antarctic
ice-cap; the radiodecay heat would cause them to melt their way down,
out of sight out of mind. It was already known then (and has
been amply confirmed since) that liquid water lies under some parts of
that ice-cap, the connection of which to the ocean was unclear but
certainly couldn't be ruled out for the timescale in question.
gasser was touted by Harwell refugee James F. Duncan, a politically
influential chemistry prof at my alma mater: rocket them into the
sun. It is surprisingly difficult to send anything from our
planet into the Sun, rather than creating a very eccentric orbit for a
cargo which might later return to Earth; and anyhow the failure rate
of big rockets before they leave the atmosphere would rule out this
Nevertheless, I have believed for a couple decades that
high-level waste could be reasonably disposed of in deep geological
formations. I suspect the fabled 'powers that be' have been
(except perhaps in the USSR) refraining from doing so because they
like to keep this issue on the boil for Greepneace etc to focus on,
drawing attention away from more difficult unsolved problems of
Published online 10 August 2010 | Nature 466,
804-805 (2010) | doi:10.1038/466804a
online: 13 August 2010
France digs deep for nuclear
Geological storage of long-lived radioactive material is moving
closer to reality in Europe, says Declan Butler.
The tunnels of the Bure laboratory are still being carved out
of the 150 million-year-old rock.B. Tinoco/ANDRA
"It'll be about 8 minutes before we reach the 490-metre lab
level," shouts an official, barely audible above the roar of
machinery, as we slam shut the heavy doors of the small lift and
trundle slowly towards the depths of the Earth.
Here, half a kilometre beneath rolling wheat fields outside the
small town of Bure in northeast France, the country is preparing to
dispose of its radioactive waste. In a ¤1-billion (US$1.3
billion) underground laboratory, the French National
Radioactive Waste Management Agency
(ANDRA) is testing the
soundness of the rock and the technologies to contain the waste.
ANDRA scientists are convinced that the rock formations can safely
house highly radioactive waste, and plan an industrial-scale facility
that would open deep below a 30-square-kilometre site nearby in 2025.
It would be among the world's first geological repositories for high-
and medium-level long-lived nuclear waste - and the largest.
The warren of tunnels under Bure is at the vanguard of several
parallel efforts across Europe to come up with a permanent home for
the long-lived waste that is accumulating at temporary storage sites.
Projects that started decades ago are finally coming to fruition.
Finland and Sweden plan to open deep geological repositories in about
2020-2025, whereas Germany hopes to open its own long-term
repository in 2035. Several smaller European countries have
banded together to form a European
Repository Development Organisation
to work on the concept of
a shared facility.
By contrast, development of the United States' only proposed
long-term repository, at Nevada's Yucca Mountain site, has stalled
again and looks set to be abandoned after two decades of work and more
than $10 billion in investment (see Nature 458, 1086-1087; 2009
). The Obama administration
wants to scrap the Yucca Mountain site, and has created a commission
to explore alternatives. One of the main problems is that the
selection of Yucca Mountain by the US Congress in 1987 was, from the
outset, a political rather than a scientific choice. "There are
far better geological sites in the US than Yucca Mountain," says
Patrick Landais, a geologist and scientific director of ANDRA, as we
tour the lab in hard hats and fluorescent overalls. Like many
experts, he questions Yucca's geological suitability: "When I
went to the top of Yucca Mountain and saw the volcanoes below, that
Efforts by the US federal government to find a site have been
stymied by opposition from individual states, where people are uneasy
about having a nuclear dump in their backyard. European countries have
taken a more scientific and stepwise approach to locating sites, which
has engendered greater public confidence - in typical Scandinavian
tradition, Sweden and Finland involved local communities in decisions
from the outset, which has increased acceptability.
Sensors in the tunnel walls monitor the rock around the
France generates about 80% of its electricity from its 58 nuclear
power plants, and is a world leader in the technology. Nuclear
power enjoys staunch cross-party support in the country, and the
economic incentives that the storage facility offers to the Bure
region have been welcomed by local officials. Anti-nuclear groups also
have little clout. Perhaps unsurprisingly, there has been little
effective resistance to the Bure facility. Mobilizing public opinion
to oppose the repository is difficult because the majority of the
French are "indifferent" to nuclear power issues, says
Sophia Majnoni, head of Greenpeace France's nuclear campaign.
The group does not oppose geological storage research, but is
concerned that plans to seal the repository after a century of use
would make it almost impossible to deal with a subsequent problem in
The Bure lab, created in 1999, has largely established the
geological suitability of the area, with its findings endorsed by
international experts. Now, it is shifting into high gear,
spending ¤100 million a year on research to pin down exactly how
waste would be stored at the planned repository. ANDRA must
present a blueprint for the repository to the government in 2014; if
approved by the French National Assembly in 2016, construction would
begin the following year. The assembly will then consider licensing
the facility to open in 2025.
Once completed, the repository would store all of the existing
2,300 cubic metres of high-level and 42,000 cubic metres of
medium-level long-lived radioactive waste - most of which has been
generated by France's nuclear power stations - as well as new waste
created over at least the next 20 years. The existing waste is
currently being stored at temporary sites in La Hague, Marcoule and
The lab itself contains no radioactive waste, and never will.
Instead, researchers at Bure are focusing on testing the rock and
prototype waste-containment strategies. Almost all of the research
results are analysed remotely. Once scientists have installed their
experiments, the output of instruments lining the tunnels is
transmitted via the Internet to ANDRA's own researchers, along with 80
collaborating labs at other research agencies and universities in
France and other European countries involved in the project. Jacques
Delay, the geologist in charge of coordination and experimental
strategies at the lab, shows me the screens of the remote data-access
system: a three-dimensional representation of the galleries in which
one can zoom in on any tunnel to find an experiment, and pull up its
data output and graphs in real time.
"The idea of a geological safe does not exist."
But dozens of scientists and engineers must still make the long
descent every day, and working at such depths is not without risk.
Before we board the lift, I get a crash course in using the chunky
'self-contained self-rescuer' device strapped around my waist.
It is a closed-circuit breathing apparatus used in the mining
industry, which can provide 20 minutes of chemically generated oxygen
should a power outage cut the tunnels' ventilation.
The lift slows at a depth of 445 metres, then creeps to the
bottom. A few minutes later, we push open the doors into galleries
crammed with scientific instruments. Incessant tannoys, and the din of
pneumatic drills and earth borers at work extending the lab, fill the
air. The tunnel walls are reinforced with concrete, steel ribs
and bolts, but here and there the grey 150-million-year-old
Callovo-Oxfordian argillaceous rock that would seal the repository is
On the pulse
Fine experimental boreholes in the walls carry about 3,500
sensors, which take the pulse of almost every mechanical, chemical and
hydrogeological aspect of the rock. The data are fed into models that
characterize the rock and also predict its future behaviour over
periods from decades to more than a million years. "No other rock
lab in the world is as highly equipped as this one," Landais
The experiments ultimately aim to answer one key question: can
France's most dangerous radioactive wastes be safely contained inside
this 150-metre-thick layer of rock? The high-level waste includes the
radioactive fission products caesium-134, caesium-137 and
strontium-90, and minor actinides such as curium-244 and
americium-241. Most nuclear fuel in France is reprocessed to extract
useful uranium and plutonium, and to concentrate the waste. Although
this high-level material comprises just 0.2% of France's nuclear waste
by volume, it accounts for 95% of its total radio°Šactivity.
Robots will store high-level waste in boreholes.
The waste is immobilized by blending it into glass, in a complex
vitrification process pioneered by the French. The molten glass is
poured into stainless steel casks, which are then placed inside steel
barrels. Robots in the Bure repository will push these barrels into
70-centimetre-diameter boreholes called alveoli, drilled 40 metres
horizontally into the walls of the main access tunnels.
The medium-level radioactive waste, meanwhile, which comes from
used reactor equipment and reagents, would be compressed into circular
cakes and piled into steel canisters, before being encased in concrete
and stored in the tunnels.
Scientists at Bure are already testing the stability of the glass
that would be used to immobilize the high-level waste, the rates of
corrosion of the stainless steel casks, and the fate of the hydrogen
gas that this degradation releases. They are also assessing all the
interactions between the glass, the layers of steel and the rock in
The canisters are designed so that heat from radioactive decay
inside does not warm their surface beyond 90 °C. Tests using mock-up
canisters have shown that prolonged exposure to this temperature does
not cause the rock to fissure. Although the volume of high-level waste
is much smaller than that of medium-level waste, it will require
double the amount of storage space, because the hot casks must be
spaced out with empty ones to avoid overheating. The scientists are
also investigating ways to reduce the volume of waste to be sent to
the facility. "Geological storage is a rare and precious
resource," says Landais. Extracting radioactive elements from
bulky graphite fuel elements and then concentrating them, for example,
could allow much more medium-level waste to be packed into the
The repository could eventually operate for at least a century,
after which it would be sealed. A few thousand years later, the
stainless steel would corrode away until it was ruptured by the
pressure of the rock, leaving the vitrified waste, and the rock
itself, to provide containment.
Rock is not an absolute barrier, says Landais. "The idea of
a geological safe does not exist." Radionuclides would slowly
diffuse through it. Of most concern at Bure are radioactive iodide and
chloride anions, which are the most mobile in this type of rock. But
Landais says that it would take hundreds of thousands of years for
them to diffuse to the surface. By that time, he says, their low
concentrations and lower levels of radioactivity would render any
environmental contamination negligible.
A more worrying problem is the possibility of a rock fracture,
which could lead to radioactive leaks. But the research at Bure has
largely confirmed that the layer of rock that would house the
repository is homogenous, highly impermeable to water movement and
free from faults and seismic risk.
At the surface, researchers are extensively sampling the air,
water and soils in a 250-square-kilometre zone around the site to get
a comprehensive baseline of environmental data. An observatory,
created jointly in April with France's agricultural research agency,
INRA, will monitor this ecosystem for at least a century.
The geologists at Bure are confident that it is a safe place for
nuclear waste. The rock is 150 million years old, hasn't budged
in the past 20 million years, and won't in the next, they say.
With the lab's panoply of sensors, measurements and models "we
might make a mistake of a few per cent, but nothing major", says
Landais. "The geology is predictable."
Clarification: The area of the repository site - 30km^2^ - refers
to its size on the surface; the underground repository itself will be