Climate change

January 14, 2009

Prescription for the Planet – Part II – Newclear energy and boron-powered vehicles

In Part I of this review, I talked through some of the logistical and ideological challenges facing society in trying to solve the climate and energy supply crises. All pretty grim. But with Part II of my review of the book Prescription for the Planet, by Tom Blees, we’re already through the nadir of depression and apparent helplessness, and on to the optimistic upslope.

The experimental sodium-cooled EBR-II nuclear reactor, which operated at Idaho National Laboratory for three decades (1964 to 1994).

The experimental sodium-cooled EBR-II nuclear reactor, which operated at Idaho National Laboratory for three decades (1964 to 1994).

This post, part II of VI, is concerned with chapters 4 and 5:

– Chapter 4: Newclear Power (pg 117-139)

– Chapter 5: The Fifth Element (pg 141-154)

The play-on-words title of chapter 4 pretty much sums it up. It’s a hand-holding walkthrough of the Integral Fast Reactor (IFR) nuclear power technology that I’ve already discussed on BraveNewClimate in two earlier posts. Blees reckons this is the new, clear choice for future power generation. First there’s some history — a description of the highly successful Argonne National Research Laboratory EBR-II reactor programme which spawned the IFR project (see diagram). Then there’s an excellent primer on basic nuclear physics for the uninitiated, which does a great job at describing how fission reactors work and the difference between thermal light water reactors (almost all present-day nuclear reactors are of this type) and fast-spectrum reactors (like IFR — though Blees tends to use the term fast breeder reactors, I tend to prefer the IPCC AR4 Working Group III terminology, because if avoids those negative historical connotations many people associate with plutonium breeders for weapons).

Importantly I think, considerable space is devoted to explaining the difference between the proliferation-resistant elecrochemical pyrometallurgical processing and recycling, compared to the proliferation-promoting PUREX (Plutonium and Uranium Recovery by EXtraction). This is a key point, because from my wider reading, I’ve concluded that weapons proliferation risk remains one of the greatest hurdle to overcome in convincing most ‘anties’ (Blees’ shorthand for anti-nuclear types) that a large-scale uptake of IFR will not heighten the risk of a catastrophic nuclear exchange or a terrorist attack using nukes.

P131 has a schematic diagram of a ‘pool design’ for a Liquid Metal cooled Fast Breeder reactor (LMFBR), like that deployed in the EBR-II. It’s stunning in its elegance and relative simplicity. The design is also ‘passively safe’, in that the inherent physical characteristics of the metal fuel pins means that should they overheat (due, for instance, to a loss of coolant flow or heat sink), they expand, and in doing so decrease their density to the point where the fission reaction simply shuts itself down. No critical  dependence on getting those graphite control rods down in time!

Incidentally, other Gen III+ advanced reactors designs also use ‘walk away’ safety measures, such as having valves holding back emergency cooling water that are held shut by the power system (so if the power goes off for any reason , the valves automatically open and shut down the reaction). But the neat thing with IFR is that it’s the fuel that does the job — although a variety of other safety features are also inherent in the IFR design. Conclusion? The chance of one of these reactors melting down, Chernobyl-style, is virtually zero (something like one in a couple of hundred million per year). I could go on here, but really, it’s better to leave it to Blees — go read Chapter 4 if you want to know more about IFR!

Now if you thought the chapter 4 material was ambitious, then chapter 5 is no let down either. In brief, it’s a proposal by Blees to replace our liquid fuel dependence — mostly related to our vehicle fleet of cars, buses, trucks etc. — with an alternative, completely recyclable energy carrier. And no, it’s not hydrogen. It’s a pure form of the semi-metal, boron — element number 5 on the periodic table (now you know where the chapter title comes from). We’re into more speculative territory here, because most of the ideas upon which Blees bases his transport fuel vision is theoretical, but it has a solid physical grounding.

For instance, it has certainly been shown that metals can ‘burn’, and that they store an incredible amount of energy per unit volume. Boron, for instance, weight for weight, stores around 6 times the energy of petrol (gasoline for the Yanks). It’s just that the fuel tank gets heavier, not lighter, as you burn it, because the combustion products accumulate as an oxide rather than being released as an exhaust gas — so it about equalises with petrol in terms of overall efficiency. To get boron to burn, you need to ignite it in pure oxygen — an idea attributed to a regular commenter at BNC, Graham Cowan — perhaps he can add some further details in the comments section. To reverse the oxidisation, you need to supply energy. Electrical energy will do — derived, for instance from… yep, that’s right, IFR power stations. It’s hard to to this chapter justice in a brief overview — you need to read it yourself to appreciate the thought Blees has put into this nascent yet ultimately very attractive idea. But for another perspective, here’s Jim Hansen’s take on it from his Trip Report (if you recall, I cited his description of IFR prospects in an earlier posting).

Boron-Powered Cars and Greenwash (Jim Hansen’s notes)

Blees properly ridicules FutureGen, commonly dubbed NeverGen, as a greenwash construction of the coal industry, intended to make it look like they were working on cleaning up their horrendous environmental damage.

Blees suggests that hydrogen-powered cars are a greenwash of the oil and auto industries, while they continue to stick us with gas-guzzlers. That charge may be too strong, but it seems fair to say that they have not been looking at alternative vehicles as hard as they should have been. Also I need to point out a possible personal bias: I have been driving a hydrogen-powered car over the past two weeks [a BMW executive recognized me on an airplane and offered a free trial – for the first time I can look my Mercedes-driving lawyer friends on the level, even though it was just a trial – don’t get excited, the hydrogen cars are not for sale, would be very expensive if they were, and there was only one place, in Jersey City boondocks, where I could fill it up].

Blees thinks that there is a superior alternative to hydrogen. Here is the basis of the idea. If a metal is ground into fine enough dust, nanoparticles, it will burn. We could burn iron-dust in our cars, capture the rust-dust, take the rust home, and cook it to drive the oxygen off, thus recovering our initial iron dust, which we then could use to power our car on its next trip. We supply energy at the time of cooking. Iron is just the energy carrier.

So iron dust is an alternative to hydrogen as an energy carrier to power our post-fossil-fuel cars. Iron dust (unlike hydrogen) has the advantage of being non-explosive, but (among other things) it is heavy and gets heavier as rust. Enter a better idea: boron. It is much more energy dense than iron: it takes a quart of boron to match the energy in a gallon of gasoline. A tank (box) of boron would cost a few hundred dollars, but you only need to buy one tankful, when you buy your car. After that you just take the boron oxide to a store, a Seven-Eleven would be happy to serve, and trade it in for a box of boron (anyone can handle this material). Blees figures that processing boron oxide back to boron would cost only tens of cents. Even if he is too optimistic (or if Exxon/Mobil sees to it that he is put 6-foot under – they are not likely to appreciate competition from Seven-Eleven), it should be much cheaper than gasoline. If the processing from B2O3 back to B is done with carbon-free electricity, it takes care of the carbon emissions problem. Blees, as you might guess, envisages the energy coming from IFR nuclear plants.

O.K., let’s go back a step. It is widely agreed that electric cars can be a solution for a piece of vehicular needs, and plug-in hybrid-electrics are a partial solution for the remaining piece. We should start with those technologies because they are ready to go, and batteries will improve, even though it has been slow going. But we must have something other than gasoline for complementing the electric part. Hydrogen, used in a fuel cell as opposed to being burned in an internal combustion engine, has the great advantage of emitting only water vapor as an exhaust product. Hydrogen could be produced at remote sites where renewable energy, such as wind or solar, is plentiful (or by IFR). But it has technological challenges, as described well in Science a few years ago, and more so in Joe Romm’s book, The Hype About Hydrogen.

Automakers have been working hard on hydrogen for several years. Some of the technological problems must have been solved. All I can say is that the hydrogen-BMW drove great, better than any car I have ever owned, with enough getty-up for even a Texas cowboy (I am not a Texas cowboy). The car also had a gasoline tank, to avoid stranding with no hydrogen, and at push of a button switched seamlessly between hydrogen and gas.

In dismissing hydrogen Blees relies in part on a note by Tromp et al. (Science, 2003) suggesting that hydrogen leakage might threaten the stratospheric ozone layer. But Michael Prather (Science 302, 581, 2003) looked harder and found that it is unlikely to be a problem with realistic hydrogen leakage rates. There are greater challenges for hydrogen, though.

Getting the price of hydrogen vehicles down to a reasonable level is a big challenge and there would need to be a distribution system analogous to gas stations, perhaps replacing them. Boron must have challenges too, but maybe less. Blees says the boron must burn in pure oxygen, which requires miniaturization of an oxygen supply system for the car. I wonder if collecting the boron oxide and converting it back to pure boron is as simple as claimed? Also, the product of hydrogen (in a fuel cell) is water vapor, which we do not have to worry about. That is the big draw of hydrogen: zero pollution. I wonder if we can burn boron without tailpipe pollution?

Bottom line: Blees has stimulating, revolutionary vision. The jury is still out on hydrogen vs boron vs something else. But I am confident that there are better alternatives than fossil fuels. It is time to start working much harder on such alternatives.

———————————————————————————

Part III will look at chapters 6 and 7, covering everything from nuclear batteries to gasified garbage!

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