Thursday, April 27, 2006

Let's start with a Bang!

Since Wunelle has provided such a warm welcome (and set the bar rather high) I figured I ought to make my debut with something big. And, as Wunelle says, I'm a 'Physics guy' and that ties right in with this.

This month marks the 20 year anniversary of the nuclear power plant explosion at Chernobyl. Greenpeace is busy taking this opportunity to use that disaster to crusade against nuclear power. I think that what Greenpeace is saying about the terrible consequences of that disaster are largely accurate - many people were killed as a direct consequence of that event, and many many more have had to suffer serious medical problems as a result.

However, Greenpeace is wrong when they use this accident as an example of why we must not use nuclear power. On the contrary - nuclear power is our best available option, especially in light of environmental issues.

When you look at the options we have for supplying the power that we all use, there are not very many environmentally friendly options that are up to the task. Solar, wind and hydro power are all great, but they will never have the capacity to meet the demands for power. Hydrogen is big lately, but hydrogen is not a power source (there aren't reserves of it stashed away somewhere), it is a power storage and transport medium, like a battery. Our current choices - coal, oil and gas are bad for the environment, and some day we will exhaust the supply. That leaves nuclear power.

I am not the only person outside of the nuclear industry who thinks this way. In fact, the founder of Greenpeace (Patrick Moore, who is no longer associated with them) has come out very publicly in favor of nuclear power specifically for environmental reasons. Moore does a good job covering the pros and cons of nuclear power, but he doesn't address one the of biggest problems of the nuclear power industry - its bad public image. Nukes scare lots of folks, and it is easy to make the case that they are exceedingly dangerous and have no place in our safety-craving world. Some folks are worried about the vast amount of energy released in nuclear reactions and others fret about all of the radiation, but I think that most of that fear originates in ignorance. People just don't know much about nuclear power and readily believe propaganda demonizing it.

Here is the simple way I view nuclear power and how it really is much better for all of us than the alternatives:

The first step in the process is to collect a lot of uranium ore. This is probably the least environmentally-friendly part of the whole process, as it usually involves large-scale mining operations, and those can leave pretty big scars. However, because there is so much energy available in nuclear reactions we don't really need to keep much of that ore, and so the vast majority of it can go right back where it came from. Compare this to coal, where HUGE quantities are hauled away to be burned and the net is a big win for nuclear.

The next step in the process is to sort through the uranium and keep the tiny fraction of it that is the right form to work in a nuclear reactor. This uranium is radioactive by nature - we do nothing to produce it or to make it radioactive - we just collect what we can find. This is the process referred to as 'enriching' and it is pretty tough to sort out just the desired uranium. The difficulty of this step is what keeps the small-time players out of the nuclear game.

Enriched uranium is quite radioactive, which just means that it is in the process of decaying via nuclear reactions. These reactions release energy as a by-product of the reaction, so the uranium emits a variety of particles that carry that energy away. That is all it means to be radioactive, and we are constantly exposed to very small amounts of radiation all of the time from traces of uranium and radon that are found in pretty much all rocks (not to mention the radiation streaming to us from sources in space, like the Sun).

This enriched uranium is then made into fuel for reactors by mixing it with materials that work to stabilize and control the pace of the reactions. The energetic particles that are emitted during a nuclear reaction can trigger a reaction in other uranium atoms - hence the 'chain reaction' of a nuclear explosion. By mixing the uranium with materials that absorb these particles it is possible to make the reactions proceed at a moderate pace. The result is a fuel rod or pellet that gets hot and stays that way for a long time.

Place a few of these hot rods or pellets in water, make the water boil, run the steam through generators and you've got a nuclear power plant.

It is actually very cool when you think about it - rather than digging up vast quantities of combustible materials and then burning them to release a small amount of energy (all the while dumping all of the exhaust into the air) we can just collect some special rocks that are naturally hot and use that heat to make electricity.

This is obviously a gross simplification, but in general it is the way nuclear power works.

After the uranium has sat around reacting for a while it is no longer useful as a fuel (some of the uranium has turned itself into other elements) and so we get to the next big problem with nuclear power - the waste. What to do with the waste is a big problem, not because it really is all that terrible, but because we as a people are unable to manage risk in a rational way.

The material that we need to dispose of from nuclear plants is just the same uranium and its reaction by-products that we dug up in some mountain. The problem is that while it was in the mountain it had been put there by nature and nobody could be at fault for the harm that it might cause someone nearby (plus it was spread pretty thin). Once we have dug it up and want to get rid of it we are now responsible for putting it somewhere and whatever happens is someone's fault. A sensible thing to do with it might be to mix it in with the tailings from the mining operations and put it back in the mountain where we got it in the first place. But that would be viewed as 'contaminating' the mountain, even though the stuff was all there in the first place.

All in all though, it is as close as we are going to come to a power source that is harmless to the environment.

Finally, I do have to address the very real issue of the sort of disaster that happened at Chernobyl. It's not acceptable to say that nuclear power is great for most of us but terrible for those unfortunate enough to suffer through its problems. The disaster in Chernobyl was not a calculated risk of using nuclear power, it was a consequence of poor design and misguided desires. We don't have to do things they way they did at Chernobyl to get nuclear power. Choices were made there to extract maximum energy at minimum expense, and the reactors were too much like bombs that they hoped to control. We can do it right and when we finally do we'll be well on our way to doing much less damage to our planet as we type away on our computers (and more).

And like Wunelle, I promise puppy pics in the near future (a little pastry as compensastion for the huge pile of salad you just digested).

6 comments:

wunelle said...

Mmmmmm. Salad. (What the hell am I saying?!)

Excellent summary. I think public perception is that WE are responsible for having MADE the material radioactive, which is a great little thing to clear up. I also think that the risk needs to be looked at with perspective: if the bad things done by the burning of fossil fuels were concentrated into episodes, we'd look at the problem quite differently.

Airlines make a good analogy: an airplane crashes and it's big news, but the numbers of people killed this way is miniscule. News coverage of highway deaths would take up several full-time TV channels (which, it must be said, would be much watched and would have no trouble finding advertising dollars, in my opinion), but because it's spread out it gets nothing like the coverage of the concentrated death and drama of a plane crash.

There's an ugly aspect to the human psyche in here somewhere, but I'm too tired to figure it out!

Joshua said...

Well, Bil, it is a simple idea that something bad happening to someone else makes us feel more lucky, or better. An optimist might say we can realize our blessings that way, a pessimist might say the same thing (but all snotty like).

Great post, but I have one question. Hydroelectric dams, however infrequently used, are a cleaner, and even more natural, power source. What is the problem with producing the landscape neccesary for these? By slightly altering the flow of some of our major waterways, we might be able to support millions more homes, for practically nothing. The displacement on wildlif ewould be minimal, and it might even bring some of those waterways closer to the people, who could then enjoy them.

Or, not.

I really did like the idea of putting the waste back, though. If we got out of our way long enough, that really would be a stroke of genius.

James Aach said...

Your comments on the adequacy of our other energy supplies, and on public perception being a problem appear right on target to me.

You might be interested to know that Stewart Brand, the founder of The Whole Earth Catalog mentioned in Dr. Moore's linked article above, has also endorsed a techno-thriller novel of nuclear power by a longtime industry insider (me). This story serves as a lay person's guide to the good and the bad of this power source. (There's plenty of both.) The book is available at no cost to readers at RadDecision.blogspot.com - and they seem to like it, judging from their comments on the homepage.

wunelle said...

I'll let Jeffy answer his own post, but for my 2 cents' worth, I agree w/ Joshua about hydro-electric power.

Though my big money would be on solar. We are bathed in untold terrawatts of energy every day, and capturing and storing it should not be so daunting, it seems. Battery technology, I guess. Any thoughts on this, O Jeffy-San?

Esbee said...

Define "we". Because while I get what you are saying, the problem lies in the dangers of those who aren't as safe as "we". It's well and good to dismiss such a concern away by saying Then those people will suffer from any fallout, it really doesn't affect us, which I've heard others say, but as a huge advocate of... of... "whole-worldism", for lack of a better term, I can't blithely go with the us/them thing.

Or are "we" going to regulate "them"?

Jeffy said...

Joshua - We do currently get quite a lot of hydro power, but we are about tapped out. The numbers I can find show that hydro accounts for about 15% of all the electric power generated worldwide. These same sources also make it sound like we have very few sites remaining where we could build more dams to get more power. Most decent remaining sites are on other continents (not that they don't also need clean energy, but it doesn't do us much good here). Also, hydro projects are not particularily environmentally friendly - they come with huge resevoirs to smooth out supply through the dry seasons, and those giant lakes cover a lot of the ecosystem. One project that is in the works up in Canada will flood an area larger than Switzerland.

Wunelle - Solar also sounds great, but there isn't as much power there as it seems. The average solar energy deposited on the US is about 125-375 Watts/square meter (this is an average over a 24 hour day). Now for the bad news - the best solar cells we can make today convert about 15% of that energy into electricity, so we can only get around .5 - 1.5 kWh/day from a square meter of cells. A typical US household would need cells covering an area about the same as the house itself, so that doesn't sound too bad. When you look at putting this on top of every single home and business, though, it amounts to an awful lot of panels (and a LOT of batteries). Places where people live in apartments or other high-density housing wouldn't have the area to meet their needs. If you look at replacing a power plant with a solar plant you are talking really huge areas - the 600MW coal plant by me would require something like 20 Million square meters (about 8 square miles) of cells. Big as this is it is a pretty small patch of land when you compare it to the area served by a 600MW plant, so if we wanted to we could meet all of our needs with solar cells (although I have no idea what the environmental impact of manufacturing that many cells and the correspondingly huge number of batteries would be).

The entire US needs (around 800,000MW) would require us to cover about 11,000 square miles with cells (or about the whole state of Maryland). Ideally we'd want to be able to generate not only enough to cover our current electricity needs, but also enough to displace our fossil fuel consumption, so we'd need quite a bit more.

In the end, may be possible to meet our needs with solar cells, but it would be tough. Maybe the answer is to use nuclear now while that is easy and work toward this sort of massive solar capacity (although I wonder about the ability of much of the world to be able to afford such a system, especially with so many cheaper options around).

esbee - I agree that we need to look at the whole-world consequences of our choices. That is what makes nuclear look so good. The 100 nuclear plants in the US have never harmed anyone, and a well-designed plant should not be able to. Fallout comes from nuclear bombs, not nuclear plants. I think that nuclear power can be good for us and for them.

Just compare the two power plants near me. The coal plant is fed an ENTIRE coal train a day. That is a mile-long string of cars that burned diesel all the way here from Montana. That is 10,000 tons of coal ground up and converted to exhaust gas every day at this one plant. The nuclear plant has no stack (because it emits no exhaust of any kind) and is powered by a 30 ton pile of uranium for a whole year. At the end of the year that 30 tons of fuel still has 95% of its energy remaining. From an environmental perspective there is just no comparison. If I could shut down one of the two plants near me I'd pick the coal plant in a second.