IFR FaD 2 – fuel use

With the Chinese announcing a projected 10-fold increase in their country’s uranium demand by 2030, some observers are worrying that we face a uranium supply crisis. In the short term, there may indeed be bottlenecks, if mining expansion fails to keep pace with escalating demand. (Frankly, I find this unlikely — price will dictate resource investment decisions over this 20 year time frame.) But what about the broader, long-term question that arises from this supply problem? How much uranium is out there, and accessible, and if the world was run entirely on IFRs (or thorium-based LFTRs), how long would we be able to do this before the ‘energy metal’ fuel supply ran out?

This is an interesting and important issue, but it’s also a little complex. So I’m going to need to devote a couple of posts to answer it properly. (Keeping in mind that I want each IFR FaD post to be concise and have a single main message). In this post, I consider how much fuel an IFR would use.

Coal, natural gas and oil, which are the feedstock used to run fossil-fuel-powered thermal generators, embody a convenient and concentrated store of ancient sunlight. But as was discovered in the 1940s, we can also unleash the vast energy contained within the atom. Indeed, splitting (‘fissioning’) the nucleus of a heavy atom like uranium, releases over a million times more energy than chemically adding oxygen atoms to carbon (which is what combustion really does). So, compared to fossil fuels, all forms of nuclear power are incredibly efficient in terms of power density.

It takes 160 — 220 tonnes of natural uranium to fuel a modern 1 gigawatt (GW) nuclear power plant for an entire year (the total energy produced is called a gigawatt year, or GWyr). One GWe of power (recall that the ‘e’ stands for electrical power rather than ‘t’ for thermal power, or heat) is a huge amount. It’s enough to run 65 million desk lamps (assuming they used 15 W compact fluorescent globes), or more practically, to satisfy today’s electricity demand of a typical Australian or US city of about half a million people. For comparison, to deliver a GWyr of energy using a coal-fired power station, about 3 — 7 million tonnes of coal must be burned (the amount can vary depending on the grade of coal).

Most of the nuclear power stations in use today are called ‘thermal reactors’, or ‘light water reactors’ (LWR). They use ordinary (‘light’) water as a coolant, which takes heat away from the reactor core. The water also acts as a ‘moderator’, slowing down subatomic particles, called neutrons, which shoot out of the atom’s nucleus when a chain reaction is underway. These neutrons are responsible for causing unstable, heavy atomic nuclei to split apart and release energy. Other reactor designs use heavy water (enriched in ‘heavy hydrogen’: deuterium) or graphite (a form of carbon found in pencils) to moderate the neutrons, but the effect is similar.

 

These nuclear power plants need, as fuel, a form (isotope) of uranium that has 143 neutrons in its nucleus, called 235-U (or ‘uranium 235’). This is also called ‘fissile’ uranium because it will readily split apart (or ‘fission’ — the term was borrowed from cellular mitosis) when it absorbs a neutron. Yet natural uranium contains only ~0.7% 235-U; almost all of the other >99% is composed of an isotope that has 3 additional neutrons, called 238-U (or ‘uranium 238’). This much more abundant isotope is called ‘fertile’ uranium. As a result, today’s LWRs are able to extract less than 1% of the atomic energy content of uranium. The rest is discarded, either as used fuel (‘nuclear waste’) or as ‘depleted uranium’. The latter, composed mostly of 238-U, is the tails left over after the fuel has been ‘enriched’ to raise the concentration of 235-U to 3 – 5%. The end product of enrichment is~27 tonnes of uranium which is suitable to be fabricated into fuel rods, and 130 — 200 tonnes of depleted uranium, which is not currently used in the nuclear fuel cycle.

Compare this to the IFR — a ‘fast spectrum reactor’. These reactors are able to not only fission 235-U like LWRs, but also readily ‘breed’ other fissionable isotopes (like 239-Pu, an isotope of plutonium) from fertile 238-U (or 232-Th for LFTRs). This is due to their fast neutrons and greater neutron production at high energies (more on this in later IFR FaD posts). With repeated recycling (more on this later, too), this allows them to unlock virtually all of the energy in nuclear fuel. The amazing upshot is that instead of using ~180 tonnes of natural uranium to produce a GWyr of electricity, IFRs (and LFTRs) require only 1 tonne* of fertile energy metals. (Hang on, if it’s so much more efficient, why aren’t we doing this right now? Long question, answer will come, you guessed it, in future IFR FaD posts).

Okay, so this is a nice, simple ‘rule of thumb’ to remember. A 1 GWe (1000 megawatt) IFR must be supplied with ~1 tonne of natural or depleted uranium per year (it doesn’t matter which). It is roughly 150 to 200 times more efficient with its fuel use than current thermal reactors.

For perspective, to supply all of Australia’s current baseload electricity demand (~30 GWe) with IFRs, we would need to supply them with 30 tonnes of uranium a year (1 tonne of uranium would fit in about two milk crates). In 2008, our mines produced 8,430 tonnes. If we instead used lignite coal (which we mostly do), we’d need to mine ~150 million tonnes of coal. This would fit into about 5,000 huge coal container ships. Spot the difference in energy density?

The above fuel figures apply to IFRs that are up and running. But what do you need to get them started? The short answer is ‘lots of fissile material’ (uranium 235, plutonium, or other transuranics) — which is a limitation. The long answer will be given in a future IFR FaD post — after I’ve taken a couple more posts to properly deal with the long-term uranium supply question with IFRs.

*see first comment, below

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39 Comments

  1. Perhaps I should also provide a brief technical justification for the 1 tonne U / GWyr figure given above.

    1 fission of a 239-Pu nucleus (bred from fertile 238-U) yields about 190 MeV of useable (non-neutrino) energy.

    A mole yields 6.023E23 (Avagadro’s constant) x 190 x 1.602E-13 (joules/MeV) = 18.3 TJ of energy.

    Thus completely fissioning 1 kg of 239-Pu gives (1000/239)*18.3 = 77 TJ = 7.7E13 joules.

    Now, 1 GWh of energy is 3.6E12 joules.

    1 GWyr (the output of a 1 GWe power station, run continuously over a course of a year) = 8760 x 3.6E12 = 3.154E16 joules.

    So we require 3.154E16/7.7E13 = 411 kg of 238-U ‘feedstock’ (bred to 239-Pu and other TRU fissile isotopes) to deliver 1 GWyr.

    Assume the IFR plant runs on a Rankine cycle at 35% efficiency operates at 90% capacity factor (in reality the efficiency and CF might both be higher), we would need 411*0.9/.35 = 1057 kg, or roughly 1 tonne of uranium.

    The actual amount of uranium used will depend on the purity of the waste stream (a topic of a future IFR FaD, if you hadn’t already guessed).

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  2. When you write ‘the purity of the waste stream’ are you refering to enrichment tailings?

    I would like to bring up another factor in the uranium supply issue, and that is distortions in the estimated reserves that comes from the way mining companies report these things. I am not accusing them of mendacity, only of practicing good business tactics by keeping certain information to themselves.

    Because of a somewhat depressed market for uranium at the moment and the very peculiar way the uranium market operates, it is unlikely that we are getting a good picture of just what long term reserves are there, and how easily they can be won.

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  3. When you write ‘the purity of the waste stream’ are you refering to enrichment tailings?

    No, I’m talking about how much residual actinides are left in the fission product waste stream after pyroprocessing. I’ll be happy to debate this in a later IFR FaD once I’ve given the context post, as I know it’s a somewhat controversial issue.

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  4. Barry there is little question that IFR type reactors can provide a lot of electricity for a long time from existing uranium stockpiles and recoverable resources. The questions about the IFR concern whether the IRF or the LFTR has the most competitive advantages. Areas to be considered include manufacturing cost, scaleability, safety and the cost, safety and cleanness of respective fuel recycling systems. These are questions that will not be resolved quickly, and we will probably be debating them for a long time to come.

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  5. In the Alberta tar patch we have an existence proof that continental surface material containing on the order of 2.5 MJ/kg, on the order of 0.7 kilowatt-hours per kilogram, of oxidation potential energy — neglecting the mass of the necessary oxygen — can be the basis of a mining operation that gets many GW of net power.

    With respect to passing once through today’s water-moderated reactors, that same 0.7 kWh/kg of energy, except from fission not combustion, can be had from terrain that yields 4.3 mass parts per million of uranium. That’s only a little higher than the average uranium-in-place — 2.2 to 2.8 mass ppm — for all of the Earth’s land surface.

    Surface stuff exists, thousands of cubic miles of it, that is tens of times richer than the average; uraniferous marine shales, for instance. The fission energy these deposits can deliver, using only reactors of the kinds that are common today, much exceeds the combustion energy that could be delivered by equally voluminous lakes of pure octane.

    (How fire can be domesticated)

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  6. Graham, that argument never gets tired, but boy is it a hard one to pound into the critics. It seems we can show all sorts of comparisons of energy density between uranium and carbon at it will never sink in.

    In all the things I have argued about on nuclear issues, I have been able to see the reasons the other side objects, or at least the source of their confusion, in this area I am at a dead loss. To me it is as obvious as the nose on your face, yet it is one of the hardest things to get others to grasp the scale that we are referring to with this.

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  7. It has always been a mystery to me that it has been so difficult for nuclear power to “break-through”… as has been said here before, the case is so clear-cut and solid it defies belief that it is not the first and highest priority in any modern energy portfolio. So what gives?

    It’s about the marketing, plain and simple. It’s been 16 years now since I was professionally involved with nuclear power, and in the interim my career has forced me to get quite deeply involved with some serious marketing campaigns… and what a long strange trip it’s been! I finally had to just stay out of it because watching a group of people agonize, sometimes for weeks… over the type of font, or choosing between three background colors so similar most people couldn’t tell the difference… well, it was just too frustrating. For a while there, I was convinced it was all a big scam… these guys were raking in BIG money, and as far as I could tell, they couldn’t even form a coherent sentence. I would stare blankly, with growing contempt, as I listened to such incomprehensible drivel as… “that font is too aggressive, its angularity is evocative of hostility”… what? … “I can’t decide if the “mauve” undertone of this shade of “putty” is more welcoming than argumentative”… huh?… GIMME MY MONEY BACK!!! They finally kept me locked out of the room.

    And yet, to my delight and complete mystification, these investments consistently paid off… handsomely. Evidently, in marketing, the visuals are the glue that makes the message stick. But I digress…

    Everyone here has gnashed their teeth at the widespread innumeracy of the general public, but that’s just the way it is… it’s no good fighting it. The problem is compounded by the scales involved with nuclear power, on both the large and small end of the spectrum… obviously the public can’t put such exponential funtions into perspective without a lot of help. To make matters worse, since its inception, the bulk of the excitement associated with nuclear power has been the domain of techno-nerds… like us! ;o) In fact, that’s probably way too generous… in the public’s mind at least, nuc’s occupy an even more rarified plane… let’s call it the “super-turbo-techno-nerd”… and who can blame them? Let’s face it, someone (like me) who gets a warm glow of satisfaction from reading a statement like, “So we require 3.154E16/7.7E13 = 411 kg of 238-U ‘feedstock’ (bred to 239-Pu and other TRU fissile isotopes) to deliver 1 GWyr.” is going to have trouble communicating with an advertising person who can state with a straight face, “The warmth of the message is contaminated with the fragrance of hyper-exactitude and made malodorous by its pugnacious inhumanity”, whose job it is to effectively convey to the Average Joe, “Wow! You mean that tiny little dot is all the fuel I need rather than that big mountain of slag?”

    At some point in time, Nuclear went West, Marketing went East, and never the twain have met. No wonder the Nuclear “brand” sucks so bad! Which brings me to my point.

    This is a great post, chock full of excellent and useful information. But I’m willing to bet that the one part that had the broadest and most compelling impact was the simple pictures of the milk crate and the container ship. That’s exactly the kind of distilled nugget that you’d expect to drop out of an adman’s incomprehensible stream-of-consciousness brain, and the kind of thing most likely to stick with the average person. Basically, for an innumerate public, a picture is worth a thousand equations.

    Here are some other suggestions…

    Do something similar with the amount of wastes generated over a year.
    -How big of a cube of the milk crate would be converted to fission products… how does that compare to a shoe, or say a deck of cards, or the original milk crate?
    -How much solid waste would the coal plant generate? How does it compare to the Eiffel Tower or the Great Pyramid, or some other landmark?
    -If all of the CO2 were pumped into a balloon at atmospheric pressure, how would it compare to… ???

    Anties don’t shrink at being very lurid about the dangers of nuclear power… turnabout is fair play. When toxicity is the topic…
    -How big of a pile in a years coal waste is stable, eternally toxic material? How does that compare to a years worth of fission products whose radiotoxicity will degrade below the original ore in 500 years or so?
    -How much raw uranium and thorium is released in coal waste fro a year – vs – the total waste from an IFR?
    -Historically speaking, how many dead bodies can we expect from both systems in a years time? How many in the last 50 years? (Morbid perhaps, but it would make a memorable graphic… tombstones to the horizon and beyond…)

    Mining impact – two identical mountains… what do they look like after a years of extraction, U – vs – coal.

    Anyway, you get the picture. Long story short… more pictures, more better.

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  8. Let’s face it, someone (like me) who gets a warm glow of satisfaction from reading a statement like, “So we require 3.154E16/7.7E13 = 411 kg of 238-U ‘feedstock’ (bred to 239-Pu and other TRU fissile isotopes) to deliver 1 GWyr.” is going to have trouble communicating with an advertising person who can state with a straight face, “The warmth of the message is contaminated with the fragrance of hyper-exactitude and made malodorous by its pugnacious inhumanity”, whose job it is to effectively convey to the Average Joe, “Wow! You mean that tiny little dot is all the fuel I need rather than that big mountain of slag?”

    Agreed — that’s why I put it in the first comment (a kind of Appendix) rather than in the main body of the post! :)

    Great suggestion about marketing, John, you’re spot on. I’m doing a new lecture series this year, in collaboration with the Royal Institution, and I want to use a range of props to plonk onto the desk in front of me as I’m talking, rather than just death by PowerPoint.

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  9. The point: are we living to see totalitarian states take the upper hand with this unlimited cheap energy?

    And our democracies vanishing in smoke and inefficiency. Like making “business” in Copenhagen?

    All civilizations have gone down because of their stupidity. Are democracies gone with the wind in fifty years?

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  10. Thank you for on excellent post! I liked the comparison between the milk crate and the container ship. Very easy to understand. If the same issue was demonstrated with big numbers only, no one would understand.

    I did a same kind of comparison with biomass and nuclear. How much of farmland would be needed to produce reed canary grass to provide the same amount of energy as will be generated by the new 1600 MW Olkiluoto-3 EPR-plant when it’s up and running.

    The text is in Finnish but the Google-translation seems to be quite satisfying:

    http://tinyurl.com/yesgyrr

    You will find a map of Finland. The blue rectangle demonstrates the area needed to fuel an 1600 MW boiler plant, as big as Olkiluoto-3. Black rectangle is the same for energy used in Helsinki, and the green rectangle for the whole Finland. What is most interesting is that the yellow rectangle demonstrates all the farmland in Finland…

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  11. Thank you John Rogers for your excellent observations. Those of us who tend to be analytical often get caught up in facts and numbers while the majority of people don’t think in those terms.

    I have on my desk a handout from NEI that I picked up at the 1st Renewable Energy conference at UNLV in Aug 2008. It has a mock “pellet” of uranium and compares the energy in that 15 mm long pinky-finger-thick cylinder: 149 gallons of oil, 1 ton of coal, 17,000 cubic feet of natural gas.

    The picture comparison of the milk crate vs container ship is like that handout. If nuclear power is to gain its rightful place as THE dominant source of base-load electricity – since that’s most commonly understood by the public what energy is for – then the nuclear power advocates need to “dumb-down” their message in order to “wise-up” the masses. KISS – Keep It Simple Sweetheart.

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  12. @Finntotal

    Excellent , though scary thought.
    Sometimes I wonder how stupid western civilization can be, even though we are supposedly “smart”.
    With the track record of humans so far, it doesn’t exactly fill me with confidence.

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  13. 1GWe Coal Plant – 5,000,000 tonnes of coal per annum.
    1GWe IFR – 30 tonnes of uranium per annum.

    My understanding is that within coal we find uranium in quanities of between 1 and 10 ppm. So 5,000,000 tonnes of coal will contain about 5 to 50 tonnes of uranium.

    In short both solutions entail the handling of about the same amount of uranium.

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  14. Terje, I’m regularly looking for “soundbytes” and that one is brilliant – thanks

    (except that, as explained above, a 1 GWe IFR uses 1 tonne of uranium, not 30 – the latter figure is the fuel required to replace all of Australia’s current baseload electricity generation).

    So the IFR solution involves handling 5 to 50 times LESS uranium than coal.

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  15. Another way to spin the soundbite might be as follows:-

    A 1GWe coal fired power station will produce between 5 and 50 tonnes of nuclear waste per annum.

    A 1GWe IFR will produce 0.X tonnes of nuclear waste per annum.

    I’ll let the nuclear / math experts figure out what X is.

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  16. Yes in *volume*. Some of the mass is converted to energy. I think 1 ton actually equals .92 tons of SNF. Someone can check the numbers. The key of course is that the radio-toxicity is reduced from 10 to 100 thousand years to about 300, when the resulting metal can be sold for scrap. Probably makes good shielding.

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  17. TerjeP (say tay-a), on December 15th, 2009 at 21.25 Said:

    … 5,000,000 tonnes of coal will contain about 5 to 50 tonnes of uranium.

    In short both solutions entail the handling of about the same amount of uranium.

    John D Morgan, on December 15th, 2009 at 21.38 Said:

    Terje, that right there should finish the argument.

    Not with those who, quite truthfully, can say they hate coal. They love it when nuclear advocates offer a coal-vs.-uranium choice. There’s an earnest, long-winded nuclear advocate over at RealClimate who always does this. No-one says boo. But when I drop by and point out that people who profit from natural gas through the taxes it pays are the heart and soul of the antinuclear lobby, that is when someone always says, do we have to have this debate here!?

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  18. The comparison to coal is still too favourable. The uranium from the coal plant is going uncontrolled into the environment, while the actinides from the reactor are tightly controlled. Big difference.

    GRLC, yes, it should finish the debate. But it won’t.

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  19. “The uranium from the coal plant is going uncontrolled into the environment, while the actinides from the reactor are tightly controlled.”

    To the point where it would be a violation of any nuclear power plants license to have a coal fire burning inside the fence.

    LNT notwithstanding, look closely at radiation release laws and regulations, and you will find coal specifically exempted.

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  20. The comparison to coal … it should finish the debate. But it won’t.

    We agree that it won’t finish the debate, but I don’t agree that it should. I say the comparison with coal is the wrong one, and plays into the natgas interests’ hands, especially the natgas royalty interests’ hand. They hate coal too, because it is too cheap and brings in too little for them.

    They are not the natgas companies. Interests, not companies. Vital distinction. Absolutely vital. People are dying as we speak because confusion has successfully been sown on this point.

    (How fire can be domesticated)

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  21. The IFR reduces nuclear waste in several ways;

    1. On a per watt basis it produces between 80 to 98% less nuclear waste than a coal fired plant.

    2. It can be fueled using existing stockpiles of nuclear waste and convert long term waste into short term waste.

    3. It can displace existing nuclear power station technology and use 99% less uranium for the same electricity output.

    Commercialisation of this technology effectively has a negative nuclear footprint and a negative carbon footprint because that would be the net effect.

    I realise this is singing to the choir.

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  22. In terms of communicating the relative quantities it might be more useful to put them on a scale people can relate to. An average house needs a supply of about 1 kW. So to provide electricity for a house for a year we can compare two options.

    React 1 gram of uranium in an IFR producing 1 gram of nuclear waste.

    Burn 5 tonnes of coal in a conventional plant and produce between 500 and 5000% more nuclear waste.

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  23. There’s a problem with the waste comparison. The ‘nuclear waste’ from coal is mostly natural uranium and thorium, and it is diluted. The ‘nuclear waste’ from a nuclear plant is a lot of things including I-131, Cs-137, Tc-99, etc. and is much “hotter” than the coal waste. An anti-nuclear advocate might pick it apart.

    Another useful comparison is that dirt (more precisely, the 2.8ppm of uranium in it) contains 7 times more thermal energy than coal, by weight.

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  24. Tweenk sez: “There’s a problem with the waste comparison. The ‘nuclear waste’ from coal is mostly natural uranium and thorium, and it is diluted. The ‘nuclear waste’ from a nuclear plant is a lot of things including I-131, Cs-137, Tc-99, etc. and is much “hotter” than the coal waste. An anti-nuclear advocate might pick it apart.”

    While this is true, a NPP does not aerosolize its radioactive waste into the atmosphere as a routine part of its operation. At any rate the real point is that there is a double standard at work here.

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  25. @Hank: I’m very much in favor of the thorium reactors, but what concerns me is that their advocates sometimes portray the uranium-based closed fuel cycle as expensive or undesirable, or even reuse some bullshit from Greenpeace.

    One of them is that uranium-based SNF needs to be stored for hundreds of thousands of years. Non-reprocessed fuel – maybe, but the thorium cycle assumes reprocessing, so it’s comparing apples to oranges.

    I think both IFR and LFTR can solve the energy problem. IFR’s advantage is that most of the research is done and there is considerable experience in operating similar designs (about 200 reactor years), while LFTR can be simpler and more reliable.

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  26. Pingback: IFR FaD 3 – the LWR versus IFR fuel cycle « BraveNewClimate

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  28. You should have completed the metaphor by saying that uranium is the leftover stores of supernovae explosions. Sunlight vs supernovae, hmmm. Yeah it becomes really damned obvious then.

    Better yet, making it explicit blows the minds of those mindless sun worshippers who think the uncontrolled unshielded thermonuclear reactor in our sky is an omnipotent deity. Even THEY possess the two brain cells it takes to know supernovae are far, FAR more powerful.

    Maybe you could convert a few of those nutters to worship of nuclear fission. It wouldn’t be quite as insane as worshipping sunlight. After all, life CAN exist without sunlight in geothermal vents. Life CANNOT exist without heavy metals and geothermal activity powered by radioactive decay.

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