Nuclear Fission for Dummies: Alpha Radiation

The Three Ways Out: Energy Tribune Magazine: January 2007 (when oil was $50 a barrel)
Any prudent observer would consider the possibility that fossil fuels might run short within years and very short within decades. Given that we depend on oil, natural gas, and coal for 90 percent of our energy, we could be facing the most catastrophic change in modern history. Equally scary, even should more fossil fuels be discovered, burning them without storing away the carbon dioxide they produce could cause global warming.
The False Ways Out

Many purported ways out are false hopes, either because they are too small to matter or because they have a fatal flaw.

- Hydroelectric power is low-cost, but cannot be expanded.
- Geothermal is available in only a few locations, and likewise cannot be expanded.
- Wind has huge potential capacity, but even in the best locations only blows fast enough to turn the windmills one-third of the time. Its fatal flaw is that we have no storage mechanism for electricity today, and none of the proposed ones would return more than 25 percent of the energy that goes in. The electricity produced by windmills could be used to make liquid fuels, but such transformations are very wasteful. If battery technology improves enough, hybrid-electric or pure electric vehicles may be the wave of the future, and full-time electric power plants (such as coal or nuclear) would avoid the conversions required by intermittent ones, such as wind or solar.
- Photovoltaic solar is many times more expensive than competing technologies, and will remain so indefinitely because sunlight is weak, the physical infrastructure costs are huge, and the sun delivers only about two thousand effective hours per year (25 percent), even in the desert. Plus, solar has the same flaw as wind: we can’t store it. Thus, while it may address peak electricity demand on a summer afternoon, it would not be reliable enough to power the world.
- Biomass as currently practiced – corn ethanol or soybean diesel – produces such small net gains in energy that no amount of farmland could ever replace a meaningful portion of our fossil fuel consumption. Corn ethanol is just a way to convert natural gas (through fertilizer and steam) into a liquid fuel. It has only gained traction because of the temporary availability of natural gas at prices lower than oil, state-level mandates, and federal-level subsidies (of 75 cents per gasoline-equivalent gallon). Soy diesel, in contrast, can be produced at a small profit, but only because we need the soy protein first. Even so, net production of 35 gallons per acre would yield less than 1 percent of U.S. petroleum consumption (2.5 billion gallons) even if all 75 million acres of soybeans were utilized. The only biomass that hasn’t been discredited as a serious energy source is cellulosic alcohol – because the proposals for it are so poorly defined no one can say what they mean. We should be skeptical because cellulose is far more difficult to break down than corn or soybeans, and the lignin that cellulose advocates propose to use for process heat is as little as 20 percent of fast-growing plants.
- Finally, while both the world and the U.S. have a lot of coal, we have yet to demonstrate even one case of large-scale long-term storage of CO2.

The Real Ways Out

Fortunately, we won’t have to live in the dark or melt all the glaciers. Conservation, efficiency, and nuclear power are real ways out.

Cutting demand (conservation) won’t be popular, but we could take at least one significant step – by curbing population growth. By 2050, the path we’re on will add 150 million people to the 300 million we reached in the U.S. this year. But the growth is driven almost entirely by immigration levels set by Congress, which Congress has the power to reduce. They just haven’t made the connection between population and energy.

Increased efficiency, particularly in transportation, space heating, and electric appliances, could generate huge savings, and many observers claim the first 50 percent reduction could be achieved with little impact on quality of life. Higher-mileage cars, better insulation, and more efficient lighting could go a long way.

But after all that, we will still need a massive source of reliable, long-lasting, low-pollution energy. And, except for a huge piece of luck, there might have been none. But we’re lucky, and one exists – nuclear fission. If, over the next 50 years, we built a thousand one-gigawatt nuclear power plants in the best known way, we could simultaneously: 1) meet all of our energy needs at reasonable cost, 2) operate them more safely than any other large-scale technology ever deployed, 3) reduce greenhouse gas emissions to a fraction of their current rate, 4) solve the waste disposal problem, 5) have a fuel supply that would last forever, and 6) add nothing to the risk of nuclear weapons proliferation.

The fundamental reason is that nuclear forces are vastly stronger than chemical bonds – about 3 million times stronger, if you compare the weight of uranium to the energy-equivalent weight of coal.

The way to unlock uranium’s full potential while minimizing its harmful by-products is to change from today’s open fuel cycle to a closed one, and from today’s fleet of light-water reactors to one containing at least some so-called fast reactors. A closed fuel cycle means reprocessing the spent fuel, in order to send the unused uranium and the created undesirable trans-uranium elements back into the reactor to be split apart, thereby releasing more energy. Only the fission products – the smaller atoms created when large ones break – would be sent to a repository. Fast reactors, which are named after the higher-energy neutrons they utilize, would serve two purposes – to burn up the trans-uranium elements and to breed new fuel (hence, the name breeder reactors) by converting the 99 percent of uranium which will not normally split into plutonium atoms which will. Light-water reactors do this, too, but on too small a scale to keep the process going. Thus they require far higher quantities of fresh uranium.

The differences would be dramatic – over 100 times more energy per ton of uranium in, and 20 times less waste per gigawatt-year of electricity produced. Even more important, the waste stream would contain so little radioactive material that after 500 years it would be no more radioactive than uranium ore in the ground. Repositories such as Yucca Mountain could be simplified or even eliminated.

How could these claims be true, you ask, since we rarely hear anyone talking about them? Because after Three Mile Island, the nuclear industry had to improve its procedures and designs, nuclear power’s opponents stopped all rational discussion, and natural gas was plentiful and cheap for a couple of decades. Nuclear power genuinely had a problem, but that’s changed.

Let’s look at these claims. Nuclear is safe enough, because even an accident which caused a large economic loss, such as Three Mile Island, harmed no one. The defense-in-depth design did what it was supposed to do, and the industry learned and applied many lessons to reduce the chance of a similar accident. We would have greenhouse gas reductions, because nuclear fission emits none. And there would be non-proliferation, because all the proposed fuel cycles mix materials in ways which would make recycled fuel undesirable for weapons design and dangerous to handle.

Nuclear power can be had at reasonable cost because: 1) the 2005 energy bill solved the unpredictable licensing process by mandating a single license for construction and operation, 2) because fast reactors will keep nuclear fuel inexpensive, and 3) because nuclear waste can be reduced to a small problem by reprocessing steps that would cost less, some say far less, than one cent per kilowatt-hour (about 12 percent of today’s average retail price).

Not that all of this will be simple. The development of closed fuel cycles and fast reactors is not yet finished. But what’s left is engineering, not the discovery of new solutions. It will take decades to build a thousand reactors, but that just underlines the task’s urgency. We can’t wait until there’s a crisis to start developing solutions, and we can’t afford to waste time on false hopes.

George Taylor is a writer in Los Altos, California who is researching a book on the feasibility, economics, and environmental impacts of all practical sources of primary energy for the next 50 years.
— George Taylor