is the longest-running and one of the largest
open pit uranium mines in the world; in 2005 it produced eight percent of global uranium oxide needs (3,711 tons). The most productive mines are the underground
McArthur River uranium mine in Canada, which produces 13% of the world's uranium, and the underground poly-metallic
Olympic Dam mine in Australia, which is mainly a copper mine, but contains the largest known reserve of uranium ore. ,
uranium and
thorium radioisotopes naturally found in coal and concentrated in heavy/bottom
coal ash and airborne
fly ash. As predicted by
ORNL to cumulatively amount to 2.9 million tons over the 1937–2040 period, from the combustion of an estimated 637 billion tons of coal worldwide. This 2.9 million tons of
actinide fuel, a resource derived from coal ash, would be classified as low grade uranium ore if it occurred naturally. In 1987, the
World Commission on Environment and Development (WCED) classified fission reactors that produce more
fissile nuclear fuel than they consume (i.e.
breeder reactors) among conventional renewable energy sources, such as
solar and
falling water. The
American Petroleum Institute likewise does not consider conventional nuclear fission as renewable, but rather that
breeder reactor nuclear power fuel is considered renewable and sustainable, noting that radioactive waste from used
spent fuel rods remains radioactive and so has to be very carefully stored for several hundred years. With the careful monitoring of radioactive waste products also being required upon the use of other renewable energy sources, such as
geothermal energy. The use of
nuclear technology relying on
fission requires
naturally occurring radioactive material as fuel.
Uranium, the most common fission fuel, is present in the ground at relatively low concentrations and
mined in 19 countries. This mined uranium is used to fuel energy-generating nuclear reactors with
fissionable uranium-235 which generates heat that is ultimately used to power
turbines to generate electricity. As of 2013 only a few kilograms (picture available) of uranium have been extracted from the ocean in
pilot programs and it is also believed that the uranium extracted on an industrial scale from the seawater would constantly be replenished from uranium
leached from the ocean floor, maintaining the seawater concentration at a stable level. In 2014, with the advances made in the efficiency of seawater uranium extraction, a paper in the journal of
Marine Science & Engineering suggests that with, light water reactors as its target, the process would be
economically competitive if implemented on a large scale. Nuclear power provides about 6% of the world's energy and 13–14% of the world's electricity. Nuclear energy production is associated with potentially dangerous
radioactive contamination as it relies upon unstable elements. In particular, nuclear power facilities produce about 200,000 metric tons of
low and intermediate level waste (LILW) and 10,000 metric tons of
high level waste (HLW) (including spent fuel designated as waste) each year worldwide. Separate from the question of the sustainability of nuclear fuel use are concerns about the high-level radioactive waste the nuclear industry generates, which if not properly contained, is
highly hazardous to people and wildlife. The United Nations (
UNSCEAR) estimated in 2008 that average annual human radiation exposure includes 0.01
millisievert (mSv) from the legacy of past atmospheric nuclear testing plus the
Chernobyl disaster and the nuclear fuel cycle, along with 2.0 mSv from natural radioisotopes and 0.4 mSv from
cosmic rays; all exposures
vary by location.
Natural uranium in some inefficient reactor
nuclear fuel cycles becomes part of the
nuclear waste "
once through" stream, and in a similar manner to the scenario were this uranium remained naturally in the ground, this uranium emits various forms of radiation in a
decay chain that has a
half-life of about 4.5 billion years. The storage of this unused uranium and the accompanying fission reaction products has raised public concerns about
risks of leaks and containment, however studies conducted on the
natural nuclear fission reactor in Oklo
Gabon, have informed geologists on the proven processes that kept the waste from this 2 billion year old natural nuclear reactor. == Land surface ==