The Nuclear Approach To Climate Change 432
Harperdog writes "A new roundtable at the Bulletin of the Atomic Scientists explores the question of whether nuclear energy is the answer to climate change, particularly in developing countries where energy needs are so great. This roundtable, like the ones before it, will be translated into Chinese, Arabic, and Spanish within a week of each article's publication. Here's a summary: From desertification in China to glacier melt in Nepal to water scarcity in South Africa, climate change is beginning to make itself felt in the developing world. As developing countries search for ways to contain carbon emissions while also maximizing economic potential, a natural focus of attention is nuclear power. But nuclear energy presents its own dangers."
Re:Honest question (Score:5, Informative)
Re:Honest question (Score:5, Informative)
Short answer: it does matter.
Longer answer: The amount of energy that we use is a small fraction of the amount of energy that the earth receives from our nearest star (aka the sun). The heat we create from the energy that we use is also a small fraction of the heat the earth retains from the sun and the earth retains in its molten core. So if we are doing something to change the amount of heat we retain from the energy we receive from the sun** with different sources of power, it could certainly make a difference.
Of course the $64G question: does buring carbon based fuels significantly change the amount of heat we retain on earth? Probably (that is the whole AGW debate). Of course we don't know for sure, but there is some evidence that it is true, but the bigger picture may be that things totally out of our control (e.g., volcanos, meteors, solar variation, etc), may in the end drown out our effect, but that doesn't mean the effect isn't there.
**for completeness, we might also consider the distribution of the heat between the surface and the molten core, but to be fair, other than the trivial amount of geothermal energy we use, there's a negligible amount to think about here.
Re:Honest question (Score:4, Informative)
And even nuclear power is a problem there - mining and enrichment are very expensive phases and they produce carbon dioxide.
It's a question of calculating the total emissions for each type of energy source, and it's not an easy process.
Add to that the environmental impact that each type of energy has, both under normal conditions and under extreme conditions. Just look at Chernobyl - that disaster made quite an impact over a large area for a long time. Fukushima wasn't as bad, and partially thanks to a large amount of the spill being diluted into the pacific.
Hydroelectric power isn't free from making an environmental impact, but it's also of a more local type and if a disaster strikes the area suffering will be usable relatively soon. Wind power has it's own problems, one is that it's not very efficient so it requires a lot of space, and the wind doesn't always blow.
Coal and oil - they are finite known resources. We better prepare ourselves for the day when they run out by looking for alternative energy solutions.
Geothermal energy is quite interesting. It's available in many locations, but requires some investment to be usable.
Re:Honest question (Score:5, Informative)
The amount of heat generated by power consumption is small compared to the energy received from the sun and emitted back into space. The earth receives around 175 PW of power from the sun, and the amount emitted back into space is around the same providing an equilibrium. The global power consumption by everyone on the planet is around 15 TW. So that's a ratio of 175 PW to .015 PW, which means we consume around .008% of the amount of power we receive from the sun / radiate into space.
A lot of our energy comes from fossil fuels, so basically that is releasing energy that was solar originally, so technically we aren't adding energy to the earth. Solar, geothermal and hydro is just converting / moving energy around from place to place within the existing system, so that doesn't add energy either. Nuclear would be the only way we'd be changing the amount of energy in the system, as we're directly converting it from mass. So it would matter what power source we use from that standpoint, and if your argument has merit, then nuclear would be the issue from an entropy standpoint.
Re:Nuclear is the answer (Thorium) (Score:5, Informative)
Thorium on the other hand produces much more power per gram and has very little waste. The waste it does produce is exceedingly less dangerous than the current 1950s style reactors.
You forgot most important part (assuming you are referring to the molten-salt thorium reactors), there is no boom. The reactor can never go out of control. Hence there is never a nuclear cloud or fall out. And also, the reactor can be designed to be started and stopped in minutes rather than hours or days or months.
Re:Honest question (Score:2, Informative)
cheap electrical power available from nukes
That's not really true.
Re:Honest question (Score:5, Informative)
but the bigger picture may be that things totally out of our control (e.g., volcanos, meteors, solar variation, etc), may in the end drown out our effect,
Total from conduction, vulcanism, and plate tectonics: 0.1 W/m^2
Total from solar variation since 1750: 0.12 W/m^2
Total from human activities so far: 1.6 W/m^2
Nothing is going to drown out our effect (Ref IPCC AR4).
For completeness, the worldwide electricity production is about 2 TW. The heat from combustible fuels not used for electricity is probably comparable. Compare this to the value for conduction, vulcanism, and plate tectonics which has a value of about 44 TW (~0.1 W/m^2).
Re:Honest question (Score:5, Informative)
things totally out of our control (e.g., volcanos, meteors, solar variation, etc), may in the end drown out our effect
the earth had reached sort of an equilibrium - CO2 released by volcanoes etcetera was being cancelled out by plants taking it out of the atmosphere, but in the latest few centuries humans have changed the co2 concentration in the atmosphere from 200/250 to 400 ppm
Re:Migrate! (Score:4, Informative)
What did it cost you to move you and your family from the continental US to Alaska? How much energy was required? And what's different about the area around what's now your home since you took up residence there?
Now multiply that by 7 billion. Well... you did say *everyone* should migrate, right?
But they'll all get to smoke a joint without being hassled, so that makes it sensible. Yeah, right.
BTW, I live just as far north as you do. Also in a place where people don't pay much heed to the War On Some Drugs.
And yet... I'm pretty sure that you've managed to contribute little or nothing of use to the discussion here.
Re:Not THE answer, but (Score:5, Informative)
This is what we saw with Fukushima. That reactor was well designed - and the others in the region held up decently. If the plant had been kept up even close to spec - there wouldn't have been a disaster. Hell, even if after the initial issue,
The reactor was well designed to faulty assumptions that in retrospect never should have been accepted.
if they had just dumped the core, it would of been a passing mention in the newspaper. Instead, somebody who valued money over other peoples lives, decided to make a profitable decision instead of a safe one.
It only takes one stupid idiot to ruin a good thing.
I'm not sure what you mean by "dump the core", but I believe the reactors all underwent a SCRAM to shut down after the quake. But even after shutdown, the reactor core continues to emit a significant amount of heat for quite some time, and when the cooling failed, there was no way to dissipate that heat.
Re:Nuclear is the answer (Thorium) (Score:4, Informative)
Experience suggests that this is an oversimplification. The HTTR (High Temperature Thorium Reactor) had a few unexpected failure modes that led to some discharge of radioactive stuff into the atmosphere. The other german experimental Thorium reactor (Juellich) almost went boom because, for some nowadays not so mysterious reason, the graphite was heated way beyond what it should have. Nobody knew that back then. While nothing happened, it still is a mayor waste problem to this day.
This leads us to another issue. The failure mode of the HTTR was not that unexpected. It was, like the Tsunami issue at Fukushima, predicted by other people and ignored by those responsible. The designers and builders of the the HTTR made a point about how they were completely sure that nothing could possibly go wrong, and whoever claimed otherwise was an idiot. Doubts were brushed aside. The moral of the story is that we cannot trust the judgement of nuclear engineers to the extent that would be necessary.
"The design is inherently safe, nothing can go wrong" -- yeah, right.
Re:Nuclear is the answer (Thorium) (Score:5, Informative)
That's why we are talking about LFTR and not the reactor type you are refering to.
The german reactor was more or less a Uranium reactor that ran on Thorium as well. A LFTR runs almost purely on Thorium, needing Urianium only as a starter.
Do NOT mix the two up.
Please make yourself familiar with that concept. Thorium is a fuel. The reactor design is somewhat independent of it.
Re:Nuclear is the answer (Thorium) (Score:2, Informative)
The thorium cycle produces Uranium 233 which is a very good weapon grade material... that's not the reason.
Re:Please Journalists, get facts! (Score:4, Informative)
As others have pointed out, building and operating the plant has to be done regardless of the energy source, so factoring that in won't change much - though admittedly historically nuclear plants have been larger and more sophisticated. There's no reason that has to be the case though - the Hyperion reactor designs for example consist of a sealed reactor unit a few cubic meters in volume that produces 70MW of heat energy for ten years. The rest of the power plant could then be a retrofitted coal-fired plant for all that it matters. Well, aside from the underground vaults protecting the reactors from accident or sabotage, but that's just a big concrete-lined hole in the ground.
As for mining - a pound of U235 contains roughly 2.3 MILLION times the energy of a pound of coal. Even once we factor in the fact that only 0.7% of uranium is the readily fissile U235 isotope, and modern light water reactors (LWR) only extract about 0.6% of the available energy that's still about 100x the energy from a pound of mined uranium than a pound of coal. Refining it cuts even further into that energy budget, but still the shear reduction in the amount of "stuff" you need to move around should make it apparent that uranium has an edge in mining energy costs. And you can reprocess the "spent" fuel, which still actually contains most of the original U235 and improve that return considerably.
And things look considerably better for Thorium, 100% of mined thorium is the fertile Th232, and it "burns" much more efficiently without reprocessing - it has roughly 10,000x the energy density of coal, and at those levels it becomes painfully obvious how much lower the CO2 emissions from mining and transportation are. Plus it's a common by-product from rare-earth mining, so you get a fair amount for "free" in that regard.
As for handling the waste - with the exception of the spent fuel, which is all valuable isotopes and should be reprocessed anyway(in a LWR) or only moderate risk relatively short-half life isotopes in a Thorium reactor, the ash from a coal plant is actually more radioactive than anything coming out of a nuclear plant, as well as being highly toxic and far more voluminous. If we held everyone to the same environmental standards I suspect coal plants would have the higher energy footprint to deal with their waste.
Re:Nuclear is the answer (Thorium) (Score:4, Informative)
Experience suggests that this is an oversimplification. The HTTR (High Temperature Thorium Reactor) had a few unexpected failure modes....
True. I was talking about Liquid fluoride thorium reactor however. It is simply not possible for this design to explode like Fukushima. When power is gone, the reaction cannot continue.
http://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor [wikipedia.org]
No, he's made a simple mistake (Score:4, Informative)
Where he is wrong is in failing to realise that this only compares like with like. If I put a big electric motor in a Chevy truck and drove it like a redneck, it would possibly result in similar emissions to the Diesel version (there are benefits because the electric motor doesn't use power when stationary, and there is no auto transmission to waste fuel). But a hybrid isn't nearly as big and heavy as a truck, and it has much better aerodynamics. If I am transporting up to 4 people plus luggage, a hybrid is far more energy efficient than a truck. The problem is people who commute in overly large vehicles, for reasons of status.
Re:Honest question (Score:5, Informative)
FYI: The Bulletin of the Atomic Scientists is a noted anti-nuclear publication. Their name comes from long ago when a number of atomic scientists put it out to oppose nuclear weapons.
This is like having the RIAA do a review on the future outlook of The Pirate Party,