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ISIS Report 11/07/05
Deconstructing the Nuclear Power Myths
Peter Bunyard disposes of the argument for nuclear power:
it is highly uneconomical, and the saving on greenhouse gas emissions negligible,
if any, compared to a gas-fired electricity generating plant
Peter Bunyard will be speaking at Sustainable
World Conference, 14-15 July 2005.
References to this article are posted on ISIS
members’ website. Details
here
Limitations due to the quality of uranium ore
A critical point about the practicability of nuclear power to provide
clean energy under global warming is the quality and grade of the uranium ore.
The quality of uranium ore varies inversely with their availability on a
logarithmic scale. The ores used at present, such as the carnotite ores in the United
States have an uranium content of up to 0.2 per cent, and vast quantities of
overlying rocks and subsoil have to be shifted to get to the 96,000 tonnes of
uranium-containing rock and shale that will provide the fresh fuel for a one
gigawatt reactor [1].
In addition, most of the ore is left behind as tailings with
considerable quantities of radioactivity from thorium-230, a daughter product
of the radioactive decay of uranium. Thorium has a half-life of 77 000 years
and decays into radium-226, which decays into the gas radon-222. All are potent
carcinogens.
Fresh fuel for one reactor contains about 10 curies of radioactivity
(27 curies equal 1012 becquerels, each of the latter being one radiation event
per second.) The tailings corresponding to that contain 67 curies of radioactive
material, much of it exposed to weathering and rain run-off. Radon gas has been
found 1 000 miles from the mine tailings from where it originated. Uranium
extraction has resulted in more than 6 billion tonnes of radioactive tailings,
with significant impact on human health [2].
Once the fuel is used in a reactor, it becomes highly radioactive
primarily because of fission products and the generation of the ‘transuranics’
such as neptunium and americium. At discharge from the reactor, a tonne of
irradiated fuel from a PWR (pressurized water reactor such as in use at
Sizewell) will contain more than 177 million curies of radioactive substances,
some admittedly short-lived, but all the more potent in the short term. Ten
years later, the radioactivity has died away to about 405 000 curies and 100
years on to 42 000 curies, therefore still 600 times more radioactive than the
original material from which the fuel was derived [3].
Today’s reactors, totalling 350 GW and providing about 3 per cent of
the total energy used in the world, consume 60 000 tonnes of equivalent natural
uranium, prior to enrichment. At that rate, economically recoverable reserves
of uranium — about 10 million tonnes — would last less than 100 years. A
worldwide nuclear programme of 1 000 nuclear reactors would consume the uranium
within 50 years, and if all the world’s electricity, currently 60 exajoules (1018Joules)
were generated by nuclear reactors, the uranium would last three years [4]. The
prospect that the amount of economically recoverable uranium would limit a
worldwide nuclear power programme was certainly appreciated by the United
Kingdom Atomic Energy in its advocacy for the fast breeder reactor, which
theoretically could increase the quantity of energy to be derived from uranium
by a factor of 70 through converting non-fissile uranium-238 into
plutonium-239.
In the Authority’s journal [5], Donaldson, D.M., and Betteridge, G.E.
stated that, “for a nuclear contribution that expands continuously to about 50
per cent of demand, uranium resources are only adequate for about 45 years.”
The earth’s crust and oceans contain millions upon millions of tonnes
of uranium. The average in the crust is 0.0004 per cent and in seawater 2 000
times more dilute. One identified resource, the Tennessee shales
in the United States, have uranium concentrations of between 10 and 100 parts
per million, therefore between 0.1 and 0.01 per cent. Such low grade ore has little
effective energy content as measured by the amount of electricity per unit mass
of mined ore [6].
Below 50 parts per million, the energy extracted is no better than
mining coal, assuming that the uranium is used in a once-through fuel cycle,
and is not reprocessed, but is dumped in some long-term repository. Apart from
the self-evident dangers of dissolving spent fuel in acid and keeping the bulk
of radioactive waste in stainless steel tanks until a final disposal is found,
reprocessing offers very little if at all in terms of energy gained through the
extraction and re-use of uranium and plutonium in mixed oxide fuel (MOX) [7].
To date, nuclear power has been built and subsidised through the use of
fossil fuels, which have provided the energy for mining, extraction, enrichment
and construction. Hence, nuclear power cannot be considered to be free of
greenhouse gas emissions. Use of the next grade down could lead to a greenhouse
gas inventory every bit as bad as for a gas-fired electricity generation plant,
and considerably worse than for a gas-fired co-generation plant, in which both
electricity and end-use heating are produced.
As Jan Willem Storm van Leeuwen and Philip Smith point out in their document
[6], the cumulative energy produced by a nuclear plant compared with the energy
expenditure shows a relatively small net gain over the course of 100 years,
which incorporates the time needed to get a handle on the costs of final disposal
of the radioactive waste, including the radioactively contaminated structural
materials of the reactor. Poor grade uranium will result in a net deficit of
energy. Hence a massive worldwide nuclear programme, based on the use of poor
grade uranium ores, will add cumulatively to energy demands, rather than resolving
them.
Gas-fired plants better than nuclear plants
On that basis, comparisons between the carbon dioxide emissions
resulting from the full once-through cycle of a nuclear plant and an
equivalently sized gas-burning plant, indicates that with the poorer uranium ores,
below 0.02 per cent, the gas-fired plant comes out better, with lower overall
carbon dioxide emissions. Indeed, the efficiency of a combined-cycle gas plant
can now achieve efficiencies of 56 per cent, more than double that achieved for
nuclear power. With gas, the costs of electricity generation have therefore
reduced in real terms.
If that gas-fired plant were to be used in co-generation, with the
simultaneous production of electricity and useful heat, it would win hands-down
for all but the best uranium ores, such as are in use today.
Quite apart from the relative paucity of good uranium ores, if the
world were to embark simultaneously on the construction of nuclear plants to
replace all coal-fired power plants, that would require one gigawatt-sized
(electrical) nuclear reactor to be built every two and a half days for 38
years. Total nuclear capacity, according to Worldwatch’s 1989 State of the
World, [8] would be 18 times greater than today, at an annual cost of $144
billion (1989 money).
In his 1990 report for Greenpeace [9] William Keepin came up with
similar numbers in terms of requirements but at a more pessimistic annual cost.
He pointed out that 5 000 nuclear plants would be needed to displace the 9.4 TW
of coal equivalent estimated to be necessary in electricity generation in the
world by 2025. Again he figured on the need to begin construction on a new
plant every couple of days, assuming a favourable six-year completion time. On
the basis of highly optimistic assumptions concerning capital costs and plant
reliability, total electricity generation costs (1990 money) would average $525
billion per year.
Nuclear power has an appalling record for long drawn-out construction
times. The last reactor to come on line in the United States took
23 years to complete. Fifteen years has been the average time taken in many
Eastern European countries using USSR technology. In France, the average time
taken for construction to operation is 8 years.
We must also not neglect the considerable and proportionately increasing impact
of other greenhouse gases to global warming. The use of nuclear power, even
to its best advantage, would not make a jot of difference to the emissions of
both methane and nitrous oxide since they are primarily derived from agriculture
and in particular from deforestation in the tropics.
France — a test case
There are other costs in running nuclear power plants. Even the nuclear
industry now admits that the generation of electricity that originates from
nuclear power is not wholly free of greenhouse gas emissions. France
provides a useful background to review the efficiency of power generation and
consumer preference. In 1999, France generated 375 TWh from its nuclear
stations. EdF (Electricité de France) estimates that the cost in CO2 emissions
of operating its nuclear plants amounts to 6 g CO2 per kWh [10].
France’s electricity board provides an estimate that
includes construction, removing the spent fuel, reprocessing and the storage of
wastes. On that basis the total CO2 emissions per year from the operation of
its nuclear plants amounts to 2.25 million tonnes. That estimate does not
include the mining and preparation of the fuel and hence is not dependent on
the quality of the ore.
On the other hand, the Öko-Institute of Germany, taking the full fuel
cycle costs into account, comes up with an average figure that is nearly 6
times higher — 35 g/kWh — compared with EdF’s, in which case the total CO2
emissions would amount to 13.125 million tonnes of CO2 equivalent [11].
In 1990, France emitted 144 million tonnes of CO2
equivalent. Therefore, nuclear power’s contribution to the total emissions
amounted to 1.6 percent on EdF’s estimates and 9.1 percent, according to the
Öko-Institute, both numbers being significant and far from trivial. Nevertheless,
banking on the naivete of the public, the nuclear industry exaggerates the
advantages of nuclear power in terms of avoided greenhouse gas emissions by
comparing its relatively low emissions compared to a coal-fired plant of the
same generating size. On that basis, nuclear power comes out 300 times better
than coal [12].
As Mycle Schneider, director of WISE (World Information on Safe
Energy)-Paris, points out, those seemingly low percentages of carbon dioxide
emission from nuclear power plants hide an elemental truth, that the use of
nuclear power in France has to be augmented, because of consumer preference, by
the use in the home of natural gas-based heating systems, both for hot water
and space-heating. For home-heating purposes electricity from whatever source
is an expensive and inefficient option, and basically the public, let alone industry,
prefers to turn away from it.
In an average French household, aside from transport, two-thirds of the
energy consumed is for heating and just one-third for electricity.
Consequently, if we are going to make any comparisons as to the carbon-economy
of nuclear power versus fossil-fuel systems, we should do so only by taking the
end-use preferences into account.
- First, the differences of any one system lie in
its efficiency to provide end-use energy whether for heating or
electricity
- Nuclear power stations are built away from population centres
- They are relatively inefficient from a
thermodynamic point of view, losing as much as two-thirds of the energy
produced as heat to the immediate environment (a body of water or cooling
tower).
- The one-third remainder of electricity must be
transmitted into a central grid system, where the losses can amount to as
much as 10 per cent
- The net result is that about one quarter of the
energy originally released gets to the consumer.
If the consumer were to obtain both electricity and heating from a
single co-generation system; the efficiency returns can amount to as much as 90
per cent of the original energy and, therefore, some three to four times better
than if nuclear generated electricity were to be the sole source of energy in
the home.
A proper evaluation of greenhouse gas emissions therefore demands that
the method of production gets taken into account when estimating the total
release of greenhouse gases. Both coal and fuel oil used in a co-generation
plant are still inferior by a factor of two to a nuclear power/natural gas
combination in terms of greenhouse emissions. But that figure is already
far-removed from the 300 times advantage so heralded by the nuclear industry
and its supporters.
Meanwhile, a natural gas co-generation system is level-pegging with the
nuclear power/natural gas combination again in terms of emissions, while being
far cheaper to the consumer simply because of the three fold better efficiency
in delivering end-use energy. And what about a co-generation system based on
biogas? The Öko-Institute estimates that it emits seven times less greenhouse
gases in providing end-use energy compared to a nuclear power/natural gas
combination [11].
Although concern over the consequences of accidents, such as at
Chernobyl or Three Mile Island impinges on the issue, the high, uneconomic cost
of nuclear power, more than any other factor, has brought about the industry’s
failure to make its mark as a major source of energy in the world.
Increasingly too, local ‘embedded’ generation, such as from a wind farm, or a
co-generation plant, is becoming an important competitor against the notion of
single large power plants attached to a central grid. In a world ever more
competitive in terms of reducing cost, an inefficient, high capital cost
nuclear power plant is increasingly an anachronism.
If nuclear power were the answer to a cheap source of energy, why has
there been a massive turning away from nuclear power since the 1970s? In the United
States, where nuclear technology originated, all civilian nuclear reactors
were ordered in the ten-year period between 1963 and 1973, all with huge subsidies
from the federal government, including so-called turn-key contracts. No new
ones have been ordered since 1973, six years before the accident at Three Mile
Island, and a string of cancellations in the 1970s and 80s plus permanent
shutdowns meant that total electricity generated by nuclear power went down
rather than up. In 1989, the cancellations and shutdowns exceeded those coming
on stream by a considerable margin, 4 GW compared to 10.4 GW.
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