Tuesday, May 03, 2005



Hard Choices II

The Listener reports that Tim Flannery, author of The Eternal Frontier and The Future Eaters - two extremely significant books about humanity's interaction with our environment - will have a new book on climate change out soon. I await it with anticipation. Meanwhile, from his interview, Flannery has a hard-headed approach to what is necessary to reduce the effects of global warming - nuclear power:

"We've got to decarbonise our electricity grids. Turn to renewables, nuclear or solar, whatever, but non-carbon-based renewables for the power grids ... nuclear power plants carry a risk, as every form of energy production does. It's a bigger risk than wind or solar, but it's not as big a risk as carbon-based fuels. In situations where it's the only viable alternative to coal, it's what we should be using."

Flannery is right; it's a hard choice, but nuclear power does seem to be the only realistic way of reducing global carbon emissions without also grossly reducing our standard of living. And if Americans or Australians want to burn uranium rather than coal, then I'm all for it.

This doesn't however mean that I'm in favour of nuclear power here. Quite apart from the strong environmental and economic reasons against it, we also have far better alternatives available. We're extremely lucky in our wind, hydro, and geothermal resources, and this should allow us to generate almost all of our power from renewable sources, without having to resort to either coal or nuclear.

17 comments:

Che: Uranium and Thorium (which is also fissionable) are limited resources - and perhaps more limited than oil was. But we can always use breeders, and burn plutonium.

The problem is that plutonium has, um, alternative uses; there's a significant proliferation risk. But this isn't an issue in countries which already have nuclear weapons and relatively good nuclear security. And conveniently, those are the very countries which use the most energy.

Posted by Idiot/Savant : 5/03/2005 09:16:00 AM

Putting the argument about needing nulear powers stations aside for the moment, except that I think we have to make a strong case somewhere for a hydro scheme and knobble the NIMBY arguments if we want to avoid a fission plant in NZ.

I personally don't object to nuclear power, it's already here to some degree. We have nuclear thermopiles in a number of sites in NZ already, the nuclear equivalent to the Diesil generator. What I would get upset about is if we don't do it ourselves.
We have uranium (radium, thorium and others too), we were even going to export, until an earthquake ruined the convienient deep sea ports, and moved all the ore 25 feet to the left.
We have built reactors here already (for research purposes), though it would be prudent to use an established overseas design and modify it for local conditions.
We even have a suitable disposal sites nearby, there's a subduction zone nearby, oh and Australia (who I think import nuclear waste).

We could do it. Quickly even. If we all have to have electric cars, we might have to.

Posted by Anonymous : 5/03/2005 09:23:00 AM

Hi Idiot/Savant

I wrote this a while ago for the kaos list: Anyway. Nuclear power,a potted summary from the geological perspective.

Useful radioactive atoms that occur in the earth: Uranium 238, Uranium 235 and Thorium 232. Of these, only U235 is capable of a sustained chain reaction. Sustained fission of _one gram_ of U235 in a moderated pile produces equivalent heat energy of burning about 13.7 barrels of oil. Exellent, lets just burn that 235, then.

Problem Numero Uno: There's fuck all 235 left, most of it has already decayed in the past five billion years or so(Drat the Oklo reactor and its Ilk. Damned ancient bacteria, burning the fissionables to warm themselves. ..wehatesit, my precious.) Naturally occuring uranium has a ratio of _one_ atom of U235 for every _138.8_ atoms of U238 (Ie: 0.72% of available uranium is fissionable in a sustained reaction.). U238 cannot sustain a chain reaction itself, and is therefore mostly NBG*. So our first problem with nuclear power is that you have to process an awful lot of ore to concentrate enough U235 to sustain a reaction - consequence, high processing cost before you have useable fissionable fuel.

The up side: if you put U238 in a U235 reactor pile, and bombard it with neutrons from the 235, you get Plutonium 239, which can sustain a chain reaction of its own. Similarly, if you put Thorium 232 in a U235 pile and do the same, you get Uranium 233, also capable of a fissile chain reaction. This is the much vaunted Breeder Reactor, which to date has mainly been used only experimentally, and nobody has sufficiently solved the technological problems to run them reliably for plutonium and U233 fuel production on a scale meaningful for generation of electricity, although they are used militarily for production of weapons grade material.

1990 world reactor numbers (dominantly U235 fueled): About 200. Favoured by France and Japan. Many of the older soviet reactors are being decommissioned. Bugger all companies want to invest in nuclear power because despite its large energy reserves, the liability insurance in case of reactor meltdowns is scary, making it a thing that governments do better than companies.

Waste: Mostly a not in my back yard problem, and you'd be surprised at the size of people's back yards when it comes to nuclear waste. Personally, I favour bulking it back out to near-natural ore deposit concentrations with silicate minerals, sintering it into artificial rocks, and dropping it down drillholes in the middle of Russia, Brazil, Saharan Africa, Eastern USA or the Yilgarn block of Aussie. Basically, a deep hole in the middle of a granite terrane, in a stable bit of crust that isnt doing much. Most of the high level waste will be fine after about 200,000 years, and if you drop it down to the middle of a nice patch of granite, the stuff is as radioactive as all fuck anyway, and its not an issue.

Fuel availability: Uranium, makes up about 0.00016% of continental crust, and thorium about four times as much. Luckily it tends to concentrate in various types of ore deposit, Uranium more so than Thorium. Due to the 1:138.8 ratio of fissionable to non fissionable isotopes, only the very richest deposits are economically viable, as the concentration costs are prohibitive for low grade ores. Ores rich enough to make U235 concentration economic available in western countries (1990 numbers) are about three and a half billion tonnes, 1/3rds of which is in Australia (Olympic Dam deposit, which the Australians seem to be dumb enough to be almost letting fall under foreign controlled mining companies. Stupid fuckers). This is about 23X10 to the 19th power Calories at 50% reactor efficiency. If breeder reactors could be perfected, then the U238, currently only a byproduct, could bring that total up to a staggering 3200X10 to the 19th power Calories.

So, ignoring breeder reactors, there is about 23 by 10 to the 19th power Calories worth of fissionable U235 reasonably available. Combined, the worlds recoverable coal, oil and gas resources are around about equivalent to 70 billion barrels of oil maybe, which is about 1.023 by 10 to the 18 Calories (If I got my conversion factors right.) Divide those numbers by average usage/year figures if you want to work out how many years of each we've got.

So, if you force the choice to fossil fuel or nuclear, we got about an order of magnitude more nuclear available, but most of that is not economically viable in any way, shape or form. Sock Theif is sadly deluded if he thinks "there's lots of uranium in granite" – there's some, but not in an economically viable extractable form – we'll be running on biofuels and compressed seagull farts before it becomes economic to bulk process granite for the fissionables at around 2.5 parts per million Uranium (most of the upper crust is granite, and thats about the average uranium level therein.) (And remember, only 0.72 % of that 2.5 ppm is U235) – the concentrations are not high enough. Nuclear could solve our energy problems until we get the dilithium crystals (or insert other unproven technobabble energy scheme here) online, but I doubt people will agree on where to put it or how to dispose of the waste.

NZ is a stupid place to build large scale nuclear reactors due to the inability of engineers to design something our earthquakes cannot crack open again.

Yours etc, Weekend Viking

*No Bloody Good, except for getting through armour plate.

Posted by Weekend_Viking : 5/03/2005 02:13:00 PM

I did read somewhere of work in doing quite the opposite of the method iarni describes for dealing with waste - e.g. separating all the isotopes using various techniques.

The motivation behind this is that there are high activity/short lived isotopes (which need a lot of shielding and cooling but decay quite quickly) and lesser activity /longer lived isotopes (which need less protection, but for longer).

I'm not sure on Uranium availability - I did read somewhere that there was more available fission energy than chemical energy in a typical lump of coal, but this may be bogus. It is definitely a fact that the availability of any raw material is proportionate to its price, and to the price of any alternatives.

To me the main indictment of nuclear power is that there is no reactor anywhere that is fully insured on the commercial market and unsubsidised by government.

Posted by Rich : 5/03/2005 04:01:00 PM

Ever heard of Minerva reefs? The Fiji-Tonga-NZ nuclear power station will be built there.

Posted by Bomber : 5/03/2005 04:12:00 PM

Minerva Reefs? That godforsaken chunk of ocean Tonga claimed back in the seventies when some 'own your own island/taxhaven' businessman tried to make it into another one of these island tax havens by dredging a few acres of coral above sea level? Thats right at the corner or thereabouts where the Tonga-Kermadec volcanic arc swings around into the various tortured bits of Fijjian volcanic arcs, and is basically close to one of the more active bits of the whole Pacific Plate? Tell me, how are they going to make their floating nuclear reactor safe against a)Yearly Hurricane Season, b)Thirty year recurrence interval major tidal wavea (thats about how often that area gets a big one from earthquakes in South America) and C) Local volcanism generated tidal waves (random)?

Thats a really good one, that one. Very funny. And they want to run a cable the length of the Tonga-Kermadec volcanic zone and expect it not to be a nightmare to maintain?

Weekend Viking

Posted by Weekend_Viking : 5/03/2005 06:05:00 PM

Oh, yes, yes the minor details of building a tsunami-proof ring around the reef and then a massive concrete ready-made sarcoghogus inside of that. Many cables cross that zone don't they? Anyway, all that to one side. That location, with all it's faults (literally and rhetorically), it is still the most preferred location for any New Zealand nuclear facility is it not?

Weekend Viking: You put your finger on it when you say "godforsaken chunk of ocean." Where else would you prefer it?

Posted by Bomber : 5/03/2005 06:55:00 PM

Most preferred locality? Well, not really. Unless someone's come up with a cable thats going to reduce the transmission loss a fair bit. If I had to put a reactor in NZ, I'd probably put it up in Northland (quite stable, geologically) or in Otago at a pinch, probably Stewart Island. Sure, having communicatons cables crossing the Kermadec zone isn't really a problem - theres redundancy, but putting a major power supply cable through the same region is a bit silly. Putting a reactor in the middle of an ocean in a known volcanic and tsunami risk area is just plain stupid.

Posted by Weekend_Viking : 5/03/2005 08:38:00 PM

I live just across the strait from Stewart Island and there is a fairly high earthquake frequency in the area...its also just about all national park except for a chunk that is maori land but managed as national park and a chunk that has people on it...both Otago and Stewart Island are a long way from where the people and a lot of the energy demand is (unless you want to give Tiwai Point an even sweter deal than it already has)

Building it on Stewart Island _would_ be an amusing way to solve the Stewart Islander's complaints about lack of infrastructure though :-)

I wouldn't build one (there's an old post somewhere on NRT about that) but if I absolutely had to it would be in Northland its geologically more stable and close to Auckland where the demand is.

Posted by Michael : 5/03/2005 09:08:00 PM

The old post Mike refers to is here.

Posted by Idiot/Savant : 5/04/2005 01:18:00 AM

I'm certainly eagerly awaiting Flannery's book as the previous two are excellent. Can also fully recommend Jared Diamond's Collapse even though I'm only half way through. Given that I'm up to the chapter on Rwanda I should probably stop reading it before bedtime.

Posted by Michael : 5/04/2005 09:19:00 AM

No, Sock Theif, Uranium is not a common element in the earth. You used the term 'very common' in a way that makes no sense. It just isnt. Period. Its a trace element present in a few parts per million, in some rocks, and almost none in others. The common elements in the earth's crust are Oxygen, at 46%, or Silicon, 27%, Aluminium, 8.13%, Iron, 5%, Calcium, 3.65%, Sodium, 2.83%, Potassium, 2.59%, Magnesium, Titanium, 0.44%, Hydrogen, 0.14%, Phosphorus, 0.12%. These are wot we in the technical trade you seem innocent of, called _Geology_, refer to technically as the Major Elements, 'cause there's a lot of them about, see. What you are referring to as a 'very common' element, is what we refer to as a 'trace element' meaning 'bugger all of it about'. This is why we use these units called 'parts per million', and note, 2.5 parts per million is a _lot_ of uranium. Most of the Mantle has only about 0.02 ppm uranium, the lower crust 0.05ppm, and granitic bits of the upper crust 2.5ppm. Oceanic crust, about .1ppm. Its not common in any sense of the word I ever have had cause to use in the mining/geological community. Go back to school, dude.

Posted by Weekend_Viking : 5/04/2005 04:22:00 PM

Oooh, we get to play qualifications one upmanship! Yay. I see your double major in geology and physics, and raise you a first class honours in geology, and trump you with a PhD in Geology. Most of the periodic table is about the place 'commonly' if all you require for common is 'available as a few parts per million' in most things. What you'd have done better to do is to be specific, and open up one of your geology textbooks, or even just plain Google it, and give Other Che a list of the crustal abundances of the elements. From which you'd learn that U238 is about as common as, say, molybdenum or arsenic, a bit less common than lead, but a lot more common than gold (by three orders of magnitude). But that hides the actual abundance of the useful fissionable stuff: U235 is present at just 0.018 parts per million, which makes it about as rare as platinum or iridium, which is a very different thing. Just telling him that its 'very common' and 'occurs in granites and sea water' is more of a rhetorical device for advancing your argument than giving him an idea of its real occurrence. You could even give him a link to its wikipedia listing, which is pretty well written. And then you'd avoid me being all sarcastic and tangential at you.

Posted by Weekend_Viking : 5/05/2005 05:00:00 PM

Nono, I'm not _complaining_ of qualifications one-upmanship, I'm _playing_ qualifications one-upmanship. Seeing as I've got my Doctorate of Philosophy already on the table, you've got to get a Doctorate of Science to trump me, now. Anyway, seeing as we have adequately sidetracked our argument away from the matter at hand, and into the ad-hominem attacks, would you like to invoke Godwin's law first, or shall I?

Posted by Weekend_Viking : 5/05/2005 05:57:00 PM

Iarni - you really are an ass
One would think a person with a Phd might have more dignity than to say "go back to school dude" in fact that is the turn of phrase one would expect from a person who was too young to have completed a Phd.
Anyway what was your thesis on?

Posted by Anonymous : 5/05/2005 07:17:00 PM

Anonymous: You are confusing authority with maturity. What on earth does having a PhD have to do with maturity, let alone dignity? It has an awful lot to do with being able to plan, undertake and write up a sizeable course of research, but that mostly involves stubbornness, not necessarily maturity. Anyway: Thesis That was a pretty general regional mapping and stratigraphic thesis, but if it helps, I'm now working on uranium lead isotope analysis with high resolution ion microprobes.

Now what I may have been trying to do in a very heavy handed way was to get some specifics into the discussion, but it seems I took too heavy an approach.

Posted by Weekend_Viking : 5/05/2005 08:43:00 PM

Qualifications one-upmanship aside, the point is that there's not nearly as much uranium as Sock Thief suggests, and that even if it becomes more valuable over time, we're still going to have to use breeders in the long-term. Which means proliferation.

Alternatively, we can simply cross our fingers and hope like hell for fusion...

Posted by Idiot/Savant : 5/06/2005 01:50:00 PM