Does nuclear energy produce no CO2 ?

8 10 2013


Another guest post by Dave Kimble at www.peakoil.org.au

Proponents of nuclear power always say that one of the big benefits of nuclear power
is that it produces no Carbon dioxide (CO2).

This is completely untrue, as a moment’s consideration will demonstrate that fossil fuels, especially oil in the form of gasoline and diesel, are essential to every stage of the nuclear cycle, and CO2 is given off whenever these are used.

Ranger Pit 1

This is Ranger Uranium Mine’s Pit Number 1.
All of the material removed from this hole, over-burden and ore, was moved by truck.

 

heavy pit truck These trucks run on diesel. It would be interesting to know how much diesel is used for how much ore in a year at Ranger.If we are to increase the number of nuclear power stations, we also need to increase the number of these trucks (which obviously take a lot of fossil fuel energy to build), and the volume of diesel fuel. Currently Australia imports 26% of its diesel consumption, and this figure is rising as our oil production falls.

The tyres on these trucks are also particularly energy-intensive to make, and there is a world-wide short of these tyres.

 

Olympic Dam uranium mill The ore is taken to a mill, usually nearby to keep trucking costs down. The mill crushes the rock to powder. The powder is then treated with sulphuric acid to dissolve the uranium, leaving the rock (depleted ore) behind.

 

tailings neutralisation The depleted ore is washed and neutralised using lime, and the slurry is pumped to the tailings ponds.

 

tailings ponds Maintaining the tailings ponds, with more diesel powered machinery.

 

Saskatchewan uranium mill Hard rock ores, such as quartz conglomerates and granites, are approximately 3 to 4 times more energy-intensive than soft rock ores (limestones and shales) to crush.

 

Ammonium diuranate - yellowcake The dissolved uranium solution, including other metals, is then treated with amines dissolved in kerosene to selectively separate the uranium, which is then precipitated out of solution using ammonia, forming Ammonium di-uranate, or “yellowcake”.All of these chemicals, sulphuric acid, lime, amines, kerosene and ammonia are energy-intensive to make, and the energy required is in the form of fossil fuels, that produce CO2 when used.

 

The calciner roasts the yellowcake to produce Uranium oxide In the final stage, the yellowcake is roasted at 800ºC in an oil-fired furnace called a calciner. The Ammonium di-uranate is converted to 98% pure Uranium oxide (U3O8), which is a dark green powder that is packed into 44-gallon drums for shipment.

 

forklift stacking yellowcake drums Drums of Uranium oxide are stacked by forklifts, while they await shipment, sometimes to the other side of the world.

 

Hydrofluoric Acid transported by rail The next stage involves dissolving the Uranium oxide in Hydrofluoric Acid and excess Fluorine gas to form Uranium hexafluoride gas :

U3O8 + 16HF + F2 => 3UF6 + 8H2O

Hydrofluoric Acid is one of the most corrosive and poisonous compounds known to man.

 

Uranium hexafluoride gas in cyclinders The Uranium hexafluoride gas is then transported in cylinders to be enriched.

 

centrifuge cascade
Naturally occurring Uranium consists of three isotopes:
U-238 = 99.2745% ; U-235 = 0.7200% ; U-234 = 0.0055%
Despite its tiny proportion of the total by weight, U-234 produces ~49% of the radioactive emissions, due to its very short half-life.

The standard enrichment process for pressurised water reactor (PWR) fuel converts this mix to:
fuel stream : U-238 = 96.4% ; U-235 = 3.6%
tailings stream : U-238 = 99.7% ; U-235 = 0.3%

The centrifuges are powered by electricity, so this stage can be powered by nuclear power. However building the centrifuge cascades requires lots of fossil fuels.

 

low enriched uranium Low-enriched (3.6%) Uranium hexafluoride gas is then transported to the fuel fabrication plant.

 

30 gram fuel pellet The UF6 gas is converted to Uranium dioxide (UO2) powder, pressed into pellets, and baked in an oil-fired furnace to form a ceramic material. These are then loaded into a tube made of a zirconium alloy. Several of these tubes form one fuel assembly.

 

fuel rod fabrication Zirconium is a metallic element derived from zircon, an ore of Zirconium silicate (ZrSiO4), which is a by-product of rutile sand mining (another energy-intensive business). Naturally occuring Zirconium is always found with Hafnium, which has to be removed (with difficulty) for nuclear uses.For every tonne of Uranium in the fuel, up to 2 tonnes of Zirconium alloy are needed.

 

fuel rod assemblies Fresh fuel is only mildly radioactive and can be handled without shielding. The fuel assemblies are then transported to the reactor by truck or train.A 1000 MW(e) nuclear reactor contains about 100 – 130 tonnes of Uranium dioxide, and usually one third of that is replaced in rotation each year.

 

The Paluel complex at Fecamp, France If you ignore the vehicles that the workers use to get to work, the reactor does not produce any CO2. But it does use electricity, as well as produce it, and to the extent that electricity is largely produced by fossil fuels, this needs to be counted in the energy balance.

 

Blast furnace chimney It takes a lot of steel and concrete to built a nuclear power station, and steel is made by smelting iron ore with coking coal.

 

Cement factory And a nuclear power station uses lots of concrete, which is made from cement. Cement is made by crushing limestone and roasting it, using fossil fuels, to drive off Carbon dioxide. So cement is particularly CO2-intensive. Concrete manufacturing is one of the highest CO2 emitters globally.

 

Reactor waste storage flask Spent fuel rods ‘normally’ spend six months in cooling ponds located within the reactor building, so that short-lived radio-activity can decay, making the material easier to handle. In the US and many other places, these spent fuel rods stay at the reactor a lot longer than that, while politicians argue over what to do with it next.

 

Reactor waste removed by truckReactor waste removed by rail Reactor waste moved by road and rail.


The Pond at Sellafield, UK

Spent fuel is kept under water until it is reprocessed. This keeps it cool and acts as a radiation shield. In the ‘once through’ process, the fuel rods are dissolved in acid, and the Plutonium is extracted, and the remainder including the Uranium becomes high-level waste. In the ‘recycling’ process, Uranium is also recovered.

 

Plutonium and MOX transport Recovered Plutonium and Mixtures of Plutonium and Uranium oxides (MOX) are sent by road back to the fuel fabrication facility to be used in new fuel rods.

 

Underground waste repository This is not really a waste repository, ( it is the NORAD military bunker at Cheyenne Mountain ) but this is what one might look like if one was ever to be built.

 

Security Police This is a security policeman, well , it does say POLICE on his bag. I do hope everything is alright.

 

Ah, that’s more like it.
How many miles per gallon do you get out of one of those ?

 

security surveillance Security surveillance is needed to prevent terrorists from getting access to radio-active materials.

 

 

Tor-M1 anti-missile missile system And increasingly these days, one also has to defend ones nuclear facilities against attack by an increasingly sophisticated enemy. This is the Tor-M1 – a fully integrated combat vehicle with anti-missile/anti-aircraft missiles, that the Iranians are getting from Russia to protect themselves from the peace-makers.


As you can see, every step of the nuclear power cycle involves the expenditure of energy derived from fossil fuels, which nuclear electricity cannot replace. Thus it is untrue to say that nuclear energy is greenhouse friendly.

In the paper “Nuclear Power : the energy balance” by J.W. Storm and P. Smith (2005) download here, the authors calculate that with high quality ores, the CO2 produced by the full nuclear life cycle is about one half to one third of an equivalent sized gas-fired power station.

 

For low quality ores (less than 0.02% of U3O8 per tonne of ore),
the CO2 produced by the full nuclear life cycle is EQUAL TO
that produced by the equivalent gas-fired power station.

 

So the question is :
Given that the greenhouse claims for nuclear power are false,
and if the only way the nuclear industry can operate is with massive amounts of cheap fossil fuels,
especially diesel derived from oil,
and with oil going to be very much scarcer in the future,
is this a good time to be thinking of increasing the nuclear industry ?

 


Related article : Confronting a false myth of nuclear power by Mary Olson, NIRS

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7 responses

8 10 2013
Graham Palmer

Hello Mike, Not related to this blog but I often see interesting articles that your readers may think worth being reproduced in Damn the Matrix. Have you heard of William McDonough? If not this is an example of his philosophy. http://www.abc.net.au/radionational/programs/newdimensions/principled-design-based-on-the-laws-of-nature-with-william-mcdo/4997172 If you are willing to receive emails directly other than in respond your blog please let me know. Kind regards, Graham Sent from my iPad

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8 10 2013
mikestasse

There are issues with copyright I constantly struggle with….. but thanks for the heads up, I will look into it.

8 10 2013
Asdfgh12345

By this logic, wind power, solar power, hydro power, etc, suck too, since mining and refining the materials, transporting them, etc. consumes fossil fuels too.

The claims about the full life cycle emissions don’t sound credible. There are much lower estimates, plus there should be much room for improvement in the technologies used.

8 10 2013
mikestasse

Well, I guess you could find better numbers, especially if they were produced by the nuclear industry…..

And of course you are right about renewables sucking too…. NOTHING we do is sustainable. Entropy rules. Soon, we will have no more than sunlight bathing the countryside as sources of energy, just like it was for millions of years.

8 10 2013
Kathleen Rickett

Very informative blog. It contains lots of very interesting information about nuclear energy and how it is being processed to form the most powerful weopons known to man. The abundance of these resources can definitely bring a country on top of the military power chain.

10 10 2013
Oelsen

The most thought inspiring picture was the plant with the cars in front of it. How much fuel does a car use? If there are 1000 Workers and their spouses driving 2 hours each day, this means 100MWh each day just for that. (is that right? Because it is somehow frightening to think about such stuff; wouldn’t it mean you could scrap this whole thing and just burn the oil to make electricity?! ffs, the suppliers all also have to drive to work!)

I like how sometimes seemingly radical ways of approaching a problem of thought can be turned around and applied to many other things. And then the approach is not so radical anymore.

10 10 2013
mikestasse

Dave Kimble, who wrote the text accompanying these photos, repeatedly says that come the day no one can drive to work, it’s game over……

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