POWER February 2017 - 37

FUELS
Global Nuclear Fuel Update
Uranium oxide, the basic fuel for nuclear power plants, has recently sold at
prices not seen in the past 13 years. In fact, the price is less than the cost
of production in many cases. That could be a problem, because little is being
done to increase the fuel supply, even though the world is adding new
and larger reactors.
Aaron Larson
L
ate last year, the Organisation for Economic
Co-operation and Development's
Nuclear Energy Agency and the International
Atomic Energy Agency released a
joint 550-page report titled Uranium 2016:
Resources, Production and Demand. It was
the 26th edition of the now-biennial report,
commonly referred to as the Red Book, with
data current as of January 1, 2015.
One potentially concerning revelation was
that total identified uranium resources had
only increased by 0.1% since the previous
report had been issued. A reason cited for the
minuscule uptick was that very little investment
had been made in exploration due to
depressed uranium market conditions.
Indeed, the price for uranium oxide (U3
O8
)
has been in a death spiral (Figure 1). In November
2016, U3
O8 was selling at prices not
seen since 2004. At roughly $18/lb, the price
was less than the cost of production for most
suppliers.
The Nuclear Fuel Supply Chain
Uranium is a metal-about as common as
tin or zinc-that is found in many rocks on
Earth in concentrations of two to four parts
per million. It is also found in seawater, but at
about three orders of magnitude less than on
land (around three parts per billion).
The nuclear fuel supply chain is divided
into four key processes: mining, conversion,
enrichment, and fabrication.
Mining. Most U.S. uranium is mined using
the in situ leach mining technique, also
known as in situ recovery (ISR). In the in situ
method, wells are drilled into the uranium
deposit, and then a solution, such as oxygenated
groundwater, is circulated through the
ore (Figure 2). That causes the rock to oxidize.
Oxidized
uranium is soluble and leaches
into the circulating solution. After the " pregnant "
mixture is pumped back to the surface,
a treatment process is used to extract the yellow-colored
uranium. The " yellowcake " is
then dried and packaged in 55-gallon drums
for shipment to a conversion facility.
While ISR accounted for about 51% of
world uranium production, conventional
1. A rollercoaster ride. The spot price for uranium peaked at about $136/lb in June 2007
bolstered by hype of a nuclear renaissance. An economic downturn and the Fukushima disaster
quickly dashed hopes of a resurgence, causing the market to plunge. Recently, U3O8 traded at
13-year low-about $18/lb. Source: The Ux Consulting Co.
2. " Well " done. In this image, uranium is
being extracted from a site near Crow Butte,
Neb., using the in situ recovery method. Wells
are drilled into the deposit and a solution is
circulated through the ore. Courtesy: Cameco
Corp.
mining techniques are also widely used. In
conventional mining, rock is excavated-either
from underground mines (about 27% of
world production) or from open-pit mines
(about 14%)-and transported to a mill. At
the mill, the ore is ground or crushed and
placed in big tanks, where it leaches into sulfuric
acid or an alkaline solution. The solution,
similar to the one produced during the
in situ process, is taken through a series of
refinement steps to extract the U3
O8
.
A few other uranium recovery techniques
not covered here make up the balance of production.
Conversion.
Although uranium is not
particularly rare, the fissile isotope (U-235)
accounts for only about 0.7% of natural
uranium. Most reactors are designed to use
enriched uranium, that is, uranium in which
the U-235 has been concentrated to between
3.5% and 5%. Before uranium can be enriched,
however, it must be converted to its
gaseous form.
During the conversion process, impurities
are removed and the uranium is combined
with fluorine to create uranium hexafluoride
(UF6
) gas. The gas is pressurized and cooled
until it liquefies. The liquid UF6
Year
February 2017 | POWER
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is drained
into 14-ton cylinders, where it is further
37
$US/lb U3O8

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POWER February 2017

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