Wednesday, April 06, 2011

Dilemmas of Nuclear Power

As a member of the steering committee of the International Peace Bureau, I went to Barcelona a couple of weeks ago for a meeting. I knew that some members already expected us to call for nuclear reactors to be shut down, world-wide, and I wasn’t ready to vote on that issue. I said that it would take me another month of serious study to reach a decision for myself, so the matter was referred to a committee for further study. Though I’m not on the committee, I will have to vote at the next meeting, if not before. Until now I had delayed taking a position because I know how complex the issue is, and I doubt that I can become sufficiently knowledgeable to trust my own conclusions.

But I’ve been reading and re-reading articles. Even now my judgment has to be tentative, for I may change my mind, but here’s the way the situation looks to me now.

The existing nuclear power plants around the world are not equally risky, but we must recognize that not a one of them can be called really safe. If the risk of such catastrophes as Chernobyl and Fukushima were the only factors to take into account, almost everyone would agree to shut them down. There are other inherent dangers in nuclear power as well, such as the challenge of hiding of radioactive wastes away for tens of thousands of years, and the danger that some of the wastes may be stolen and used for a nuclear weapon by terrorists or some enemy state. The potential for proliferation of weaponry should give everyone serious concerns about proceeding with these plants.

But there are three other types risk that must be considered and balanced against the nuclear ones:
  1. the impending shortage of fuel on which our standard of living (perhaps even the survival of billions of human beings) depend;
  2. the risks of alternative sources of energy, such as the health hazards of burning coal and the environmental dangers of “fracking” the earth to remove natural gas; and
  3. looming climate crisis, which also threatens the survival of billions of us.
If we reject nuclear power completely, can we develop other sources of fuel quickly enough to sustain modern civilization? And if we reject nuclear power, will our use of other sources of energy heat the planet so much that its self-regulatory feedback system will be ruined?

Different analysts reach different conclusions. Optimistic studies say that it is barely possible, but even they do not say it will be easy to get along without nuclear power. I will refer here to several articles from the Internet, plus one in The Economist of March 26th, pp 79-81.

At present only about 14 percent of the world’s energy comes from nuclear sources, though the amount varies significantly from one country to another. In France it is 80 percent; in the US, 20 percent, in Japan, 30 percent. It would not be difficult to make up the difference if we had to shut all power plants down, but there would be several disadvantages. For example, we might depend on coal, which when burned emits soot, sulfur and mercury, already killing far more people per kilowatt hour than nuclear does. It also would warm the planet appreciably, whereas we must reduce global warming to less than 2 degrees C, mainly by reducing carbon dioxide emissions to 44 billion tonnes by 2020.

The most ambitious actions that countries could take would bring the emissions down to about 49 billion donnes, leaving a gap of 5 billion tonnes. Nuclear power can reduce emissions by only about 2 billion tonnes—but that’s a significant amount when we consider the devastating effects on the planet of failing to limit warming.

However, nuclear power is expensive. A Canadian researcher, Trevor Findlay, has reviewed the prospects for a “nuclear renaissance”—the renewed growth of that industry, and has decided that it is unlikely to occur. When planners begin comparing the real costs of various types of energy, they often change their minds and abandon plans for a new power reactor. That was true even before the Fukushima disaster, and now if there are to be new plants they will probably cost even more because additional safety features must be built in.

The most promising alternative to nuclear power would be natural gas, which is mostly methane. According to The Economist, it will do more than renewables to limit the world’s carbon emissions. It emits far less CO2 than coal and 30-40 percent less greenhouse gas than gasoline-driven cars. Natural gas has become plentiful recently because of new technologies of extraction. It is possible to drill into a seam of shale and then drill sideways, curling around as necessary to reach the gas. Fortunately, methane also costs less and pollutes less than petroleum engines. But it too has disadvantages—including its toxicity, its explosiveness, and the costliness of the pipelines that it requires. Still, because it is plentiful, it is going to be used more in the future and it is hard to argue against that prospect, especially since it can be used as a “baseload” fuel, unlike the renewables solar or wind power, which are hard to store and are produced only when the sun shines or the wind blows.

But natural gas will not save us. So far as I can ascertain, the world is highly unlikely to reduce carbon emissions enough to restrain climate change to bearable levels. It is actually too late now to make the changes that are required. We will have to choose between burning coal, with its detrimental health and climatic effects, or nuclear, with other detrimental effects on health, the environment, and the proliferation of nuclear weaponry. And even the use of coal and nuclear will probably not suffice to limit climate change.

Yet I do not despair yet. There are several grounds for hope. If future carbon emissions remain disastrously high, there are ways of removing it from the ambient atmosphere and sequestering it. A huge campaign of re-forestation would go far toward that goal, and changes in agricultural practices can also help a great deal. For example, no-till farming keeps the carbon in the soil instead of exposing it to the atmosphere. Moreover, the widespread but appropriate production and burial of biochar would enable us to sequester about 12 percent as much carbon dioxide each year as we emit through the use of fossil fuels.

Moreover, there are grounds for hope even if we find it necessary to use nuclear power. Nuclear technology has been moving through several stages of improvement. The existing power plants in the world are Generation Two. There are well-developed designs for certain Generation Three plants, though none have been built yet. And within twenty years or even less, Generation Four plants can be ready.

It is these fourth generation reactors that give cause for hope. As the eminent climate scientist James Hansen has noted,

“They can burn nuclear waste, turning our biggest headache into an asset. The much smaller volume of waste from fourth generation reactors has a lifetime of a few centuries, rather than tens of thousands of years. The fact that fourth generation reactors will be able to use the waste from third generation plants changes the nuclear story fundamentally, making the combination of third and fourth generation plants a much more attractive energy option than third generation itself would have been.”

The most promising of these upcoming forms of nuclear power is the “thorium reactor.” A ton of thorium can produce as much energy as 200 tons of uranium and 3.5 million tons of coal. It is an abundant metal and a highly efficient fuel source, all forms of which can be used as fuel—unlike natural uranium, which must be highly refined before it can be used in nuclear reactors. The best use of thorium would be in a network of tiny underground nuclear reactors, too small to require the enormous security system that a full-sized nuclear power plant needs.

Thorium solves the non-proliferation problem, for its reactors produce only a small amount of plutonium. Even traces of unburned U-233 in a thorium reactor are more difficult to convert to a usable nuclear weapon than Uranium 235 or Plutonium 239. The waste from burning thorium in a reactor is dramatically less radioactive than conventional nuclear waste. Such waste would only need to be locked up for about five percent as long as most nuclear waste.

Unlike uranium and plutonium, thorium is not fissile. It cannot sustain a nuclear reaction once it has been started but fizzles out unless it receives ongoing boosts to keep it going. For this it could be mixed with other fuels or kept running by an ongoing particle beam. If that particle beam stops, the whole reactor would stop; it could not melt down. There is no chance of a Chernobyl-type accident. It can dispose of weapons–grade plutonium and can also be developed as a fuel for many conventional reactors to prevent production of any further plutonium as a by-product.

It would seem, then, that the fourth generation reactors solve all the problems that alarm us. Their fuel sources are abundant and safe; they can be used to burn up the waste products remaining from current nuclear reactors; they will produce much less waste than today and it can be more easily managed; and they are not suitable ingredients for nuclear weapons. If that is so, and especially since they will enable us to cut carbon dioxide emissions markedly and limit climate change, why should we object to them?

The existing nuclear power plants are dangerous. No more of them should be built, and some of them should be dismantled—which will happen to many of them anyway because of their age.  But I cannot in conscience argue against the development of fourth generation nuclear power plants. We are going to need all possible ways of getting by with the fuel resources available to us, and keeping our planet from cooking. Fourth generation nuclear plants seem potentially useful for that purpose. Unless some new information comes my way that challenges the findings I’ve mentioned above, I will vote at the next IPB meeting to support the production of fourth generation nuclear power.

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Anonymous Norman Rubin said...

Metta, your nuclear percentages of energy are off by a factor of five, because they're really nuclear percentages of electricity, which is typically ~20% of a modern society's energy. Neither electricity nor nuclear nor coal is quite as large or as important as your numbers would suggest.

I, too, have no absolute or "religious" objections to a theoretical reactor that creates no problems. But I remain to be convinced that 4th-gen a/o thorium-fueled reactors will become that mythological beast. I'd support a perpetual-motion machine in my basement, too. I've even seen some designs that look plausible, until you get close enough to try to make them work. That's been my experience with nuclear power reactor designs, so far: the artist's conceptions look better than the reality, the promoters are more voluble about the strengths than the weaknesses, and none of them can repay their investments in the marketplace, or we'd already have them.

If somebody wants to build one of those small Thorium-fueled reactors, without needing my tax or rate guarantees to do it, I'm not stopping them, and I won't, unless I discover strong reasons to wish them ill (or run them out of town). But I don't expect to be faced with that choice -- just the choice of whether or not to offer them gadzillions of public dollars to get a few steps closer to "practical".

By stating your "support" for such chimeras, I fear you are just offering your own tax and rate dollars for abuse. I'd rather that you listed your objections to today's nuclear power plants, and (like me) expressed your complete willingness to reconsider, if and when those objections are overcome.

7:09 PM  
Blogger Metta Spencer said...

Thanks, Norm. I wonder what I should read to get the correct numbers. If I am off by a factor of five, I'd better revise the piece. Otherwise, I suppose the main thing I should do is reiterate my statement that my conclusions are extremely tentative. If thorium is as good as the articles I read have claimed, then hooray for them. But if you are skeptical, I certainly had better remain so as well. But I do think we have to take account of all these contradictory considerations. My friends in Barcelona were willing just to say no to nuclear power without regard to what that might mean for the other issues, such as climate change and energy shortage. How do you weigh\ these things against each other?


8:53 PM  
Blogger Norman said...

I wouldn't spend much time trying to nail down cost-benefit numbers on distant, theoretical, "4th-gen" reactors. Fusion might arrive sooner, or neither of them may end up being worth doing.

Potentially cost-effective technologies are being described and analyzed every day (including weekends) by "beggars and choosers", i.e., potential investors, and people looking for investors. They occasionally make mistakes (and pay dearly for them), but they are very good at what they do.

Technologies that are NOT potentially cost-effective are being pitched to government agencies and lobbyists and others who might connect them to taxpayer subsidies or ratepayer guarantees. To identify those, you usually just have to wait to hear the pitches for unearned money.

If thorium reactors could only work in huge sizes, there might be some investor aversion that proponents would call irrational. But they sound like they can be small and scalable -- and maybe much less inherently hazardous than today's reactors. If a chunk of that is true, then finding willing investors, willing regulators, and willing neighbors, should be relatively easy. If one or two of those are easy, the discussion should be going public. But if all of these are difficult or impossible, then it should tell us something, and we've both saved a bunch of time we could never get back.

12:07 AM  
Blogger Metta Spencer said...

Thanks again. The reasonable thing to do, if I accept your arguments (and I wouldn't dispute them) would be just to sit tight and take no position until enough information accumulates to make one course of action seem decidedly preferable. I prefer to do just that. But the world insists that people take positions. As a member of IPB's steering committee I will have to vote. What I am proposing is that the IPB take NO position now, since we need more information than is available. I think they want to go on record as urging all governments to shut down nuclear power plants, which of course would have no influence on governments at all anyway. I am just saying that 4th generation inventions MAY be okay and we ought to leave room for that possibility. So far as I can tell, even if my numbers are wrong, my proposal is not grossly different from your own.

8:56 AM  

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