The Resilient Earth: Science, Global Warming and the Fate of Humanity

by Simmons, Allen

  Today, fear of nuclear power lingers. In an August 15, 2007 interview on NPR's Morning Edition, David Whitford, editor-at-large at Fortune magazine, demonstrated the media's ingrained aversion to nuclear power when he was questioned about the future of the industry. Commenting on the 50 years nuclear power has been in use, Whitford said: “During that time, there have been two terrible accidents: Three Mile Island and Chernobyl. Chernobyl was by far the worst. You had a meltdown, an explosion and 75 people, according to the UN, died as a result of the accident.” He continued grudgingly, “Three Mile Island, the best hard evidence that I found, was that no one was significantly harmed.”560

  Two “terrible” accidents, one where 75 people died and a large area was contaminated with radioactivity that persists to this day, the other where no one was significantly harmed. Chernobyl was undoubtedly a disaster, but Three Mile Island was not. At TMI all of the safety features worked, disaster was averted. Yet, in the eyes of the media, the two events are equivalent. Saying that TMI was a terrible accident is like saying that an airplane that loses an engine on takeoff, but still manages to land safely, had a terrible crash. What is the attitude towards nuclear power in other countries? Germany and the Scandinavian nations, in particular, seem to suffer from the same aversion as America. Other countries take a more practical and pragmatic approach.

  Worldwide, there are 439 nuclear reactors in 31 countries supplying 15% of all electricity generated. In the 50 years of commercial nuclear power generation over 12,700 reactor years of service have been logged—in that time, the only fatal accident at a commercial plant was Chernobyl (Illustration 159). Despite being the only country to have suffered the devastating effects of nuclear weapons in wartime, Japan has embraced the peaceful use of nuclear energy. Today, nuclear power accounts for about 34% of the country's total electricity production. In April 2006, the Institute of Energy Economics of Japan forecast that, by 2030, nuclear energy's portion will increase to 41%. By that time, ten new nuclear power stations will come on-line.

  Illustration 159: Cumulative reactor hours, showing TMI and Chernobyl accidents. Source IAEA.

  In France, unlike America, nuclear energy is accepted and even popular. A country that, like Japan, has few natural energy resources, France's decision to launch a large nuclear program dates back to 1973. When events in the Middle East led to the quadrupling of oil prices by OPEC, the French faced what they refer to as the “oil shock.” At that time, France generated most of its electricity by burning oil and had no choice but to go nuclear. Today, France has 56 working nuclear plants, generating 76% of its electricity.561

  Some argue that safety issues and nuclear waste are too intractable to even consider nuclear power. C'est de la merde, as the French say. The only catastrophic nuclear accident occurred at an incredibly primitive, poorly designed, and haphazardly run reactor in the old Soviet Union—a reactor that no modern nation would allow to be built on its soil today. In America, and the other technically advanced nations, nuclear power has proven to be among the safest energy sources available. In the US, this has been achieved with reactors designed and built in the 1960s. Compare a modern automobile with a car from the 1960s. Though the cars of the '60s seemed advanced and modern at the time, today they are amusing, if crude and smelly, antiques. Similarly, nuclear power technology has improved tremendously in the past four decades. Newer, more modern reactor designs are even safer and more efficient than their safe and reliable predecessors.

  As for the fear of radiation coming from nuclear power plants, note that radiation is found everywhere in nature. Radon gas is found in rock structures and house basements from New England to Georgia. Our bodies contain radioactive isotopes of carbon, potassium and other elements—fortunately at low concentrations. The burning of coal releases radioactive materials that naturally occur in coal. People who live near coal-fired power plants are exposed to higher levels of radiation than those living near nuclear plants.

  Creating a sustained nuclear fission reaction is not simple. A nuclear power plant is a large, complex, high-precision piece of engineering, carefully designed to create conditions that allow the splitting of uranium atoms. To keep such a plant operating requires the involvement of many scientists and technicians, who constantly monitor and adjust the plant mechanisms. Because creating fission is so hard, many people think that nuclear power is not natural—that nuclear fission is something unnatural that man has unwisely created. That is why it came as a great surprise to most when French physicist Francis Perrin announced that nature had preceded humans, creating the world's first nuclear reactors almost two billion years ago.562

  Illustration 160: Configuration of the Oklo natural nuclear reactors. Source U.S DOE.

  In 1972, fifteen natural fission reactors were found in three different ore deposits at the Oklo mine in Gabon, West Africa. Collectively known as the Oklo Fossil Reactors, these natural atomic piles lie deep under African soil. About 1.7 billion years ago, natural conditions prompted underground nuclear reactions to take place. Scientists from around the world have studied the rock at Oklo to gain an understanding of how this could happen. Scientists believe that water filtering down through crevices in the rock played a key role. Without water, it would have been nearly impossible for natural reactors to sustain chain reactions.563

  In 1956, while at the University of Arkansas, Dr. Paul Kuroda described the conditions under which a natural nuclear reactor could occur. When the Oklo reactors were discovered, the conditions found there were very similar to his predictions. Acting much as it does in human built reactors, water served as a moderator, slowing the neutrons emitted by radioactive uranium atoms. Without being slowed, these neutrons would collide with other atoms with so much energy, they would bounce off. Slowing the neutrons allowed them to be absorbed by the atoms they collided with. The added neutrons destabilized any uranium atoms that absorbed them, causing the atoms to split. This created two lighter atoms while releasing heat and more neutrons, which split even more atoms—a chain reaction was created.

  When the heat from the reactions became too great, the moderating water turned to steam, which was incapable of slowing the neutrons. The chain reaction shut down until the reaction zone cooled and liquid water could return. Then the process would begin again. It is thought that the natural nuclear reactors operated continuously for 150 million years, releasing heat energy at an average power of 100 kilowatts.564

  When these underground nuclear reactions ceased, nature showed that it could effectively contain the radioactive wastes they created. The radioactive remains of natural nuclear reactions that took place 1.7 billion years ago in Africa never moved far beyond their place of origin, deep underground. They remain contained in the sedimentary rocks, which kept them from being dissolved or spread by groundwater. Nature's example makes scientists confident that human built storage sites, like the one being constructed at Yucca Mountain, can contain the radioactive wastes with similar effectiveness. We have learned from nature's example, nuclear power and the waste it generates can be safe if handled properly.

  Which is more manageable; 6,500,000,000 tons of CO2, emitted by hundreds of millions of sources worldwide, or a few thousand tons of waste from a few hundred locations? There are a number of highly excitable “ecologists” who will tell you this “deadly” waste must be stored safely for 10,000 years—some even say 1,000,000 years. Trying to permanently bury nuclear waste for longer than human beings have been on Earth is utter foolishness.

  Though nature has safely stored nuclear waste for more than 1.5 billion years, it has been pointed out by real world engineers that permanently interring waste material and hoping for the best is not the optimum solution. A better approach is to leave the storage facility unsealed and constantly monitor the condition of the stored material. This allows action to be taken as needed in the future. This adaptable solution also allows for the use of improved disposal technology as it becomes available. In truth, we need only safely store
the nuclear waste from decommissioned plants for a few hundred years, knowing that future engineers will revisit the problem when warranted.

  An even better option is to recycle spent nuclear fuel, reclaiming the highly radioactive waste products including plutonium that are produced by fission reactions. France has been doing this all along, greatly reducing the amount of waste their plants produce. A new multinational association called the Global Nuclear Energy Partnership (GNEP) is promoting an improved recycling process that does not separate plutonium from the other highly radioactive waste products. This prevents the plutonium's use in nuclear weapons while allowing the waste to be used as fuel for so called “fast” reactors. At the same time the volume and toxicity of the waste are reduced, more energy is extracted from the spent fuel. After this process, most of the remaining waste would need to be stored for only a few hundred years. William Hannum, a nuclear physicist formerly at Argon National Laboratory, has said that this process is so efficient that “for all practical purposes, the uranium would be inexhaustible.”565

  The final argument used against nuclear power is that it is too expensive and only exists because of government subsidies. Nuclear power plants do cost more than oil or gas fired plants, but once they are built, their operating costs are minimal while the cost of fossil fuels is high and bound to go higher. The Energy Information Agency (EIA) calculates that the average wholesale cost of electricity in the US is 5 cents a kWh. The Nuclear Energy Institute estimates the average generating cost for nuclear power is 1.7 cents per kWh. Why then, do people say nuclear costs too much? The main factors are delays caused by regulations and law suits.

  Construction of the Shoreham reactor in New York was begun in 1973, but the plant never entered service. This was due to strong local opposition that brought about delay after delay, preventing the plant from ever producing usable power. Because of interest costs over time, the price tag for the plant rose from an initial $70 million to $6 billion when the plant was finally decommissioned in 1994.566 In other countries, such as France, where both the people and the politicians accept the benefits of nuclear power, delays are minimal and costs much lower.

  As we have seen, there is a choice to be made in energy production. Renewable sources will not meet present day needs, let alone tomorrow's energy demands. Coal and other fossil fuel use should be reduced, not increased. Solar and perhaps fusion lie in the distant future, but for now, the only proven, clean, rational choice is nuclear power. Just as cars, cellphones, and computers improve with time, so does nuclear reactor technology. Our ability to build more efficient nuclear plants, contain radioactive waste, and lower energy costs will only grow in the future, particularly if we follow the GNEP recycling scheme.

  Many environmentalists remain opposed to nuclear power, even in the face of the supposedly more imminent threat of global warming. Several green luminaries such as Patrick More, a founder of Greenpeace, James Lovelock, originator of the Gaia Hypotheses and president of the Marine Biological Association, and Stewart Brand, creator of The Whole Earth Catalog, have changed their stance on nuclear power and now embrace it. Nature shows us the way—it is time for those who reject nuclear power to overcome their fears and get serious about reducing GHG emissions.

  A Step Farther Out

  If the desire is for truly clean power in the future, perhaps we should look to an idea from the past. Four decades ago, the idea of a solar power satellite in stationary orbit was hotly debated. The proposed stationary solar power satellite (SSPS) would collect energy from the Sun using an array of lightweight mirrors, use that energy to generate electricity, and then beam the energy to Earth as microwaves. Optimistic assessments thought the SSPS would be cost-competitive with nuclear power, but the technology of the time would have been tested to the breaking point.

  More recently, NASA rechristened the idea Space Solar Power (SSP) and formed a study group to reevaluate the concept. After studying the problem from 1995-2001, John C. Mankins, who headed up the project, concluded that SSP is viable and could be operating by the 2020s. In contrast to existing renewable power sources, solar power from space would provide an uninterrupted, 24-hour supply of carbon-free power. Another estimate, from the George C. Marshall Institute, found that an SSP system could meet Europe's power needs by 2030 with a production cost of about $.05/kWh.567

  The SPS system is composed of a space segment, the Solar Power Satellite (SPS), and a ground power receiving site. The ground station uses an antenna array to receive and convert the microwave power beam back into electricity. The receiving device is called a rectenna, for rectifying antenna, and would be about 6 by 9 miles (10 by 15 km) in area.

  Conceptually, an SPS is very simple. It is a large satellite designed as an electric power plant orbiting in the Geostationary Earth Orbit (GEO). It consists of three main components: a solar energy collector to convert sunlight into electricity, a DC-to-microwave converter, and a large antenna array to beam the power to the ground. The solar collector can be either photovoltaic cells or a solar thermal turbine. The DC-to-microwave converter of the SPS can be either a microwave tube system and/or a semiconductor system. The third component is a sizable microwave antenna array. Because the microwave beam is so wide, the power density of the beam would only be around 0.024 W/m2, low enough to not harm wildlife.

  Such a satellite would have a large surface area, dwarfing the current International Space Station. Estimates for a gigawatt received capacity SPS using solar cells require an array area of approximately 1.25 by 3 miles. This would produce 2 GW DC power at the satellite. Optimum size of the transmitting phased array is around a mile across and the optimum microwave power of a few GW at 2.45 GHz. The DC to microwave RF conversion efficiency, including all losses (e.g. from phase shifters, power circuits, and isolators), is around 80%. The beam collection efficiency back on Earth, would be about 90%. Absorption by the atmosphere less than 2%. Such a system would deliver a bit more than 1 GW of power to the grid.568

  Advanced solar cells convert 40% of the light energy they receive into electricity. DARPA funded research is projected to increase efficiency to 50%. Increased efficiency makes solar cells more productive, but they will remain expensive for the foreseeable future. If expensive solar cell arrays are to be used, the best place for them would be in orbit, above Earth's atmosphere. As we have seen, most of the Sun's energy striking Earth is either reflected back into space or absorbed by the atmosphere. Placing solar cells outside the atmosphere allows the reception of full strength, full spectrum solar radiation. Another advantage is that, due to the tilt of Earth's axis, a power station placed in GEO is in nearly perpetual sunshine, only occasionally passing through Earth's shadow. Unlike earthbound solar cells, which are in darkness 50% of the time, SPS cells are in the light 98% of the time.

  Unfortunately, NASA disbanded the SSP research group headed by Mankins. As Martin Hoffert, Professor Emeritus of Physics at New York University, put it “we don't do energy at NASA.” The US DOE is also not interested in the SSP concept because they don't do aerospace. While we are generally not in favor of large government programs, such an experimental enterprise, costing an estimated $100 billion to develop and build the initial satellite, is more than any commercial company can take on. Certainly, this would be a space program with tangible benefits here on Earth.

  Plan Summary

  Satisfying the world's need for clean, non-polluting energy is a gigantic problem—but not an insolvable one. The future will no doubt provide technological breakthroughs, though what form these will take, and when they will emerge, cannot be predicted. In the meantime, we need to apply the best available technology to solve the problem. Already significant advances are being made in aviation, automotive, and power storage technologies. Wind, geothermal and hydroelectric generation can help ease the demand for green energy, but will not be able to solve the problem on their own. Solar can help as well, but barring dramatic reductions in cost, it will remain a minor energy source. Even with
optimistically high efficiency improvements (10-20%), the hard truth is the world must turn to nuclear power—at least as a bridging technology until better solutions become available. Here are the main points of our plan:

  Use renewable energy where economically viable. This includes hydroelectric, geothermal and wind power.

  Aggressively pursue the development of hybrid transportation technologies. This includes trains, buses, trucks and automobiles.

  Build only energy efficient new buildings and homes. Utilize both passive and active solar heating and power. Use renewable building resources such as timber from managed forests.

  Overhaul national and continental power grids. Switch to DC transmission and add off-peak storage systems to make the most productive use of variability in wind and solar power.

  Actively work on improving solar power technology, both on Earth and in space.

  Rapidly expand nuclear power capacity. Adopt safe recycling of spent nuclear fuel and advanced reactors.

  These are things we can and should do today. There are also things we should not pursue. These include biofuels, “clean” coal and tapping methane ice deposits. The potential return on these technologies are poor, or the potential for environmental disaster exceeds any possible gain.

  One of the actions that Kyoto and many others have promoted is creation of so called cap-and-trade carbon trading schemes. Under this type of emissions limiting system, the government sets a maximum amount of allowed pollution, the cap. Polluters are issued credits that permit them to emit a fixed amount of carbon. If a carbon credit holder reduces their emissions, they can resell or trade their excess credits to other, dirtier enterprises. This type of scheme has a spotty history for effectiveness. The US sulfur emissions program has worked fairly well, but the EU emissions trading scheme, instituted in 2005, has been a disappointment.569