Environmental Engineering Reference
In-Depth Information
3
Nuclear
From its discovery in 1789 until World War II, uranium was mined mostly for its radium content,
which was sought for use as luminous paint for watch dials and other instruments, as well as for
health-related applications. The by-product uranium was used mostly as a yellow pigment. In the
United States, uranium ore was found in 1871 in gold mines near Central City, Colorado, which
produced about fifty tons of high-grade ore between 1871 and 1895. However, most American
uranium ore before World War II came from vanadium deposits in the Colorado Plateau of Utah
and Colorado (Dahlkamp 1993).
Domestic reserves of uranium are reported by the U.S. government in terms of “maximum-
forward cost” estimates that do not include some costs of development, such as sunk costs for
exploration and land acquisition, income taxes, profit, and the cost of money. Consequently, this
may result in somewhat optimistic estimates of recoverable reserves. As of December 31, 2008,
U.S. forward-cost uranium reserves were estimated at about 1,227 million pounds of uranium
hexafluoride (U
3
O
8
) at US$100 per pound, or 539 million pounds of U
3
O
8
at US$50 per pound
(USEIA 2010d), reflecting the difference in reserves at various market prices. The weighted-average
price of uranium purchased by owners and operators of U.S. civilian nuclear power reactors in
2011 was $55.64 per pound of U
3
O
8
(USEIA 2012c, Table S1b). U.S. production of uranium
concentrate (yellowcake) was 3.99 million pounds in 2011 (USEIA 2012a, Table 3), most in Utah,
Nebraska, Texas, and Wyoming.
The nuclear fuel cycle includes exploration, mining, processing, transportation, utilization,
decommissioning, and disposal of waste by-products and spent fuel (see
Figure 3.1
). Human
exposure to radiation is associated with each of these activities, and each stage of the nuclear fuel
cycle generates radioactive wastes.
Uranium prospecting is similar to exploration for coal in the United States (see
Chapter 2
in this
volume), but relies upon some specialized instruments for detecting the presence of radioactive
isotopes. Ionization chambers and Geiger counters were first adapted for field use in the 1930s.
They were the principal instruments used for uranium prospecting for many years until Geiger
counters were replaced by scintillation counters. The use of airborne ionization chambers and
Geiger counters to prospect for radioactive minerals began in the 1940s. Airborne gamma-ray
spectrometry is now the accepted leading technique for uranium prospecting worldwide.
After a search of available records, site visits by geologists are followed by core drilling
and logging of boreholes to determine the amounts of uranium materials that are extractable at
specified costs from a deposit. Uranium reserves are the amounts of ore that are estimated to be
recoverable at stated costs.
Exploration for uranium produces significant environmental damage similar in quality and scale
to that caused by coal exploration as described in detail in
Chapter 2.
Such damage is particularly
40
Search WWH ::
Custom Search