PLENTIFUL ENERGY

First, remember, natural uranium as mined is 99.3% composed of the isotope U-
238 and 0.71% of U-235. Only the U-235 is fissionable (there‘s a small
contribution from U-238) in conventional light water reactors. Their fuel is enriched
initially to a U-235 concentration of 3% to 5%. The energy produced is about
equally split between fission of the U-235 and of the Pu-239 produced in operation
by neutron capture in U-238. The heat from these reactions is used to drive steam
turbines in a cycle whose conversion efficiency is about 33%. The fuel is replaced
when the U-235 concentration has decreased to about 1%, which corresponds to a
residence time in the reactor of about three years. A 1 GWe (1,000 MWe) light
water nuclear plant refuels about twenty tonnes of fuel a year; it actually consumes
only a tonne or so, with the rest currently going to waste. (A tonne is a thousand kg,
or about twenty-two hundred pounds.)
It is worth noting that a coal-fired plant of comparable size consumes about ten
thousand tonnes of coal per day, millions of tonnes per year. (The basis of the
difference is very fundamental: Typical chemical processes emit about twenty
electron volts of energy per reaction, whereas a nuclear fission reaction releases two
hundred million electron volts, and therefore yields about ten million times more
energy than do chemical processes; thus the huge difference in the amount of fuel
required.) Nuclear energy is very concentrated: a very little fuel gives a very large
amount of energy.
The overall picture for uranium is typical of a fairly common mineral in the
earth‘s crust. It has an average crustal abundance of about 2.7 ppm, about the same
as zinc. There is an estimated forty trillion tonnes of uranium in the earth's crust. To
date, we have mined less than one ten-millionth of this. World consumption of
uranium currently is some seventy thousand tonnes a year. To give a feel for
contribution to power cost, a price of $100/lb ore, more or less the current spot
market price, contributes about 0.55 cents per kWh, about 25 percent, to the price of
nuclear generated electricity when used in LWRs.
At prices of $100/lb recently, a considerable amount of new exploration has
resulted in an increase in both the known and the estimated amounts of uranium.
The worldwide uranium resources data are jointly compiled by the OECD Nuclear
Energy Agency and IAEA, updated every two years. [8] The ―Identified Resources‖
reported in 2009 was 5.404 million tonnes as compared to the 4.743 tonnes reported
in 2005. The ―Identified Resources‖ category consists of ―Reasonably Assured
Resources‖ and ―Inferred Resources.‖ In addition, ―Undiscovered (Prognosticated
and Speculative) Resources‖ are estimated at 10.4 million tones at around this
$100/lb recovery price.
The substantial increase in identified resources is the result of renewed
exploration effort, and the increase in activity has continued. The exploration
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