Uranium in Sea Water
To properly asses the danger of uranium and radioactive waste it is first important to gain a sense of proportion:
1. How much uranium is available in the earth's crust.
2. How much uranium is eroded by streams and rivers and dumped in the oceans.
3. How slowly does uranium give off its radiation when found in nature.
One of the standard textbooks on the subject of Nuclear Power is by Bernard Cohen and is called The Nuclear
Energy Option, which was published in 1990. It is now offered for free on the Internet at:
http://www.phyast.pitt.edu/~blc/book/index.html
The crust contains 6.5x10^13 ton of uranium. That is 65,000,000,000,000 tons of uranium.
Rivers bring more uranium into the sea all the time, in fact 32,000 tons per year.
An amazing 4.6 billion tons of uranium are estimated to be in sea water.
Consider that the extraction of uranium
Japanese scientists in the 1980s proved that extraction of uranium from sea water using ion exchangers was feasible.
The half-life of uranium-238 is about 4.47 billion years and that of uranium-235 is 704 million years. Under normal
conditions, it is not giving off much radiation given that it obviously takes so long to decay.
In 1983, uranium cost $40 per pound. The known uranium reserves at that price would suffice for light water reactors
for a few tens of years. Since then more rich uranium deposits have been discovered including a very big one in
Canada. At $40 per pound, uranium contributes about 0.2 cents per kWh to the cost of electricity. (Electricity retails
between 5 cents and 10 cents per kWh in the U.S.)
Breeder reactors use uranium more than 100 times as efficiently as the current light water reactors. Hence much
more expensive uranium can be used. At $1,000 per pound, uranium would contribute only 0.03 cents per kWh, i.e.
less than one percent of the cost of electricity. At that price, the fuel cost would correspond to gasoline priced at half
a cent per gallon.
How much uranium is available at $1,000 per pound?
There is plenty in the Conway granites of New England and in shales in Tennessee, but Cohen decided to
concentrate on uranium extracted from seawater - presumably in order to keep the calculations simple and certain.
Cohen (see the references in his article) considers it certain that uranium can be extracted from seawater at less
than $1000 per pound and considers $200-400 per pound the best estimate.
In terms of fuel cost per million BTU, he gives uranium at $400 per pound=>1.1 cents , coal =>$1.25, OPEC oil
=>$5.70, natural gas =>$3-4.
http://www-formal.stanford.edu/jmc/progress/cohen.html
How much uranium is there in seawater?
Seawater contains 3.3x10^(-9) (3.3 parts per billion) of uranium, so the 1.4x10^18 tonne of seawater contains
4.6x10^9 tonne of uranium. All the world's electricity usage, 650 GWe could therefore be supplied by the uranium in
seawater for 7 million years.
However, rivers bring more uranium into the sea all the time, in fact 3.2x10^4 tonne per year.
Cohen calculates that we could take 16,000 tons per year of uranium from seawater, which would supply 25 times the
world's present electricity usage and twice the world's present total energy consumption. He argues that given the
geological cycles of erosion, subduction and uplift, the supply would last for 5 billion years with a withdrawal rate of
6,500 tonne per year. The crust contains 6.5x10^13 ton of uranium.
He comments that lasting 5 billion years, i.e. longer than the sun will support life on earth, should cause uranium to
be considered a renewable resource.
Here's a Japanese site discussing extracting uranium from seawater.
http://peakoildebunked.blogspot.com/2006/01/208-uranium-from-seawater-part-2.html
The Japanese have been refining the processes for extracting Uranium from seawater for decades. The Japanese
have extracted 1 kg of uranium from seawater. Two proposals to take the Japanese concepts and radically alter them
using synthetic biology for fictionalized algae blooms or for nanomembranes currently used in desalinization.
Next
To properly asses the danger of uranium and radioactive waste it is first important to gain a sense of proportion:
1. How much uranium is available in the earth's crust.
2. How much uranium is eroded by streams and rivers and dumped in the oceans.
3. How slowly does uranium give off its radiation when found in nature.
One of the standard textbooks on the subject of Nuclear Power is by Bernard Cohen and is called The Nuclear
Energy Option, which was published in 1990. It is now offered for free on the Internet at:
http://www.phyast.pitt.edu/~blc/book/index.html
The crust contains 6.5x10^13 ton of uranium. That is 65,000,000,000,000 tons of uranium.
Rivers bring more uranium into the sea all the time, in fact 32,000 tons per year.
An amazing 4.6 billion tons of uranium are estimated to be in sea water.
Consider that the extraction of uranium
Japanese scientists in the 1980s proved that extraction of uranium from sea water using ion exchangers was feasible.
The half-life of uranium-238 is about 4.47 billion years and that of uranium-235 is 704 million years. Under normal
conditions, it is not giving off much radiation given that it obviously takes so long to decay.
In 1983, uranium cost $40 per pound. The known uranium reserves at that price would suffice for light water reactors
for a few tens of years. Since then more rich uranium deposits have been discovered including a very big one in
Canada. At $40 per pound, uranium contributes about 0.2 cents per kWh to the cost of electricity. (Electricity retails
between 5 cents and 10 cents per kWh in the U.S.)
Breeder reactors use uranium more than 100 times as efficiently as the current light water reactors. Hence much
more expensive uranium can be used. At $1,000 per pound, uranium would contribute only 0.03 cents per kWh, i.e.
less than one percent of the cost of electricity. At that price, the fuel cost would correspond to gasoline priced at half
a cent per gallon.
How much uranium is available at $1,000 per pound?
There is plenty in the Conway granites of New England and in shales in Tennessee, but Cohen decided to
concentrate on uranium extracted from seawater - presumably in order to keep the calculations simple and certain.
Cohen (see the references in his article) considers it certain that uranium can be extracted from seawater at less
than $1000 per pound and considers $200-400 per pound the best estimate.
In terms of fuel cost per million BTU, he gives uranium at $400 per pound=>1.1 cents , coal =>$1.25, OPEC oil
=>$5.70, natural gas =>$3-4.
http://www-formal.stanford.edu/jmc/progress/cohen.html
How much uranium is there in seawater?
Seawater contains 3.3x10^(-9) (3.3 parts per billion) of uranium, so the 1.4x10^18 tonne of seawater contains
4.6x10^9 tonne of uranium. All the world's electricity usage, 650 GWe could therefore be supplied by the uranium in
seawater for 7 million years.
However, rivers bring more uranium into the sea all the time, in fact 3.2x10^4 tonne per year.
Cohen calculates that we could take 16,000 tons per year of uranium from seawater, which would supply 25 times the
world's present electricity usage and twice the world's present total energy consumption. He argues that given the
geological cycles of erosion, subduction and uplift, the supply would last for 5 billion years with a withdrawal rate of
6,500 tonne per year. The crust contains 6.5x10^13 ton of uranium.
He comments that lasting 5 billion years, i.e. longer than the sun will support life on earth, should cause uranium to
be considered a renewable resource.
Here's a Japanese site discussing extracting uranium from seawater.
http://peakoildebunked.blogspot.com/2006/01/208-uranium-from-seawater-part-2.html
The Japanese have been refining the processes for extracting Uranium from seawater for decades. The Japanese
have extracted 1 kg of uranium from seawater. Two proposals to take the Japanese concepts and radically alter them
using synthetic biology for fictionalized algae blooms or for nanomembranes currently used in desalinization.
Next
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