Powering the Future: A Scientist's Guide to Energy Independence

by Daniel B. Botkin

  By the early 1980s, with not a single plant working, the cost of the entire project reached an estimated $14 billion, and the WPPSS board stopped construction. Because the nonoperating plants brought in no money, WPPSS defaulted on $2.25 billion due in bonds. And who was stuck with the bond debts? A lot of small investors who had trusted a state bond issue to be a safe way to save for retirement. In some small towns where unemployment due to the recession was already high, this amounted to more than $12,000 per customer.

  There were lots of bondholders, and they sued, as did various parties involved in the design and construction, who sued each other, and the matter wound its way through the courts for 13 years. In 1988 the parties settled for $753 million. That settlement involved 30,000 bondholders, some of whom got as little as 10–40 cents on each dollar they had invested.

  Two famous nuclear disasters

  Three Mile Island

  Although nuclear engineers and big power companies have said for years that nuclear reactors are safe, the reality is that nuclear reactors emit considerable, undesirable amounts of radiation into the environment even during “normal” operation, and when mistakes are made, they have led to some spectacular disasters.

  One of the most dramatic events in the history of U.S. radiation pollution occurred on March 28, 1979, at the Three Mile Island nuclear power plant near Harrisburg, Pennsylvania. The malfunction of a valve, along with human errors, resulted in a partial core meltdown—the neat lineup of rods of uranium and graphite and the materials holding them got so hot that the whole thing melted, releasing intense radiation into the interior of the containment structure. This kind of accident was precisely what the containment structure was designed to contain, and it mostly did. Still, some radiation was released into the environment. Three days after the accident, radiation levels near the Three Mile Island nuclear power plant were six times higher than the natural background radiation. (There is always some radiation in our environment, some coming from outer space as cosmic rays, some from naturally occurring radioisotopes in the soil and bedrock.)

  Since the long-term chronic effects of exposure to low levels of radiation are not well understood, the effects of Three Mile Island exposure, although apparently small, are difficult to estimate. However, the incident revealed many potential problems with the way U.S. society has dealt with nuclear power.

  Since nuclear power had been considered relatively safe, the state of Pennsylvania was unprepared to deal with an accident. For example, there was no state bureau for radiation help, and the state Department of Health did not have a single book on radiation medicine. (The medical library had been dismantled two years earlier for budgetary reasons.) One of the major impacts of the incident was fear; yet there was no state office of mental health, and no staff member from the Department of Health was allowed to sit in on important discussions following the accident.

  Chernobyl

  The worst nuclear power plant accident occurred in 1986 at Chernobyl in Ukraine (which was then part of the Soviet Union). The World Health Organization estimates that 4,000 people have died as a direct result of this accident.35 Experts estimate that this release will cause 39,000 cancer deaths in Europe over a period of 50 years following the accident.

  Lack of preparedness to deal with a serious nuclear power plant accident was dramatically illustrated by events that began unfolding on Monday morning, April 28, 1986. Workers at a nuclear power plant in Sweden, frantically searching for the source of elevated levels of radiation near their plant, concluded that it was not their installation that was leaking radiation but that radioactivity was coming from the Soviet Union by way of prevailing winds. Confronted, the Soviets announced that an accident had occurred at a nuclear power plant at Chernobyl two days earlier, on April 26. This was the first notice to the world of the worst accident in the history of nuclear power generation.

  It is speculated that the system that supplied cooling waters for the Chernobyl reactor failed as a result of human error, causing the temperature of the reactor core to rise to more than 3,000°C (about 5,400°F) and melting the uranium fuel. Explosions blew off the top of the building over the reactor, and the graphite surrounding the fuel rods used to moderate the nuclear reactions in the core ignited. Some reports suggest that the energy of the blast was 200 times greater than that released by the Hiroshima and Nagasaki atomic bombs taken together.36 The fire produced a cloud of radioactive particles that rose high into the atmosphere. Within a short time, there were 237 confirmed cases of acute radiation sickness, and 31 people died.

  In the days following the accident, nearly 3 billion people in the Northern Hemisphere received varying amounts of radiation from Chernobyl. With the exception of the 30-km (19-mi) zone surrounding Chernobyl, global human exposure was relatively small. Even in Europe, where exposure was highest, it was considerably less than the natural radiation people receive during the course of a year. In that 30-km zone around Chernobyl, however, about 115,000 people were evacuated; and as many as 24,000 people were estimated to have received a dangerous dose. We are told that this group of people is being studied carefully.

  One apparent effect is that since the accident the number of childhood thyroid cancer cases per year has risen steadily in Belarus, Ukraine, and the Russian Federation (the three countries most affected by Chernobyl). In 1994 a combined rate of 132 new thyroid cancer cases were identified. Since the accident, a total of 1,036 thyroid cancer cases have been diagnosed in children under 15. These cases are believed to be linked to the released radiation from the accident, although other factors, such as environmental pollution, may also play a role. It is predicted that a few percent of the roughly 1 million children exposed to the radiation will eventually develop thyroid cancer.

  Outside the 30-km zone, the increased risk of cancer is very small and not likely to be detected from an ecological evaluation. Nevertheless, according to one estimate, Chernobyl will ultimately be responsible for an additional 16,000 deaths worldwide.

  Chernobyl had other environmental effects as well. Vegetation within 7 km of the power plant was either killed or severely damaged by the accident. Pine trees examined in 1990 around Chernobyl showed extensive tissue damage and still contained radioactivity. The distance between annual rings (a measure of tree growth) had decreased since 1986.

  Interestingly, scientists returning to the evacuated zone in the mid-1990s found, to their surprise, thriving and expanding animal populations. In the absence of people, species such as wild boar, moose, otters, waterfowl, and rodents were enjoying a population boom. The wild boar population had increased tenfold since the evacuation of people. Still, these species may be paying a genetic price for living within the contaminated zone. A study of gene mutations in meadow voles (also called field mice) within the zone found more than 5 mutations per animal, compared with a rate of only 0.4 per animal outside the zone. It is puzzling to scientists that the high mutation rate has not crippled the animal populations, but it appears so far that the benefit of excluding humans outweighs the negative effects of radioactive contamination.

  In the areas surrounding Chernobyl, radioactive materials continue to contaminate soils, vegetation, surface water, and groundwater, presenting a hazard to plants and animals. The evacuation zone may be uninhabitable for a very long time unless some way is found to remove the radioactivity. For example, 5 km from Chernobyl, the city of Prypyat, which had a population of 48,000 at the time of the accident, is today a “ghost city,” abandoned, with blocks of vacant apartment buildings and rusting vehicles. Roads are cracking and trees are growing as new vegetation transforms the urban land back to green fields. Cases of thyroid cancer are still increasing, and the number of cases is many times higher for people who lived as children in Prypyat at the time of the accident.

  The final story of the world’s most serious nuclear accident is yet to completely unfold. Estimates of the total cost of the Chernobyl accident vary widely, but it will probably exceed $200 billion.37


  Although the Soviets were accused of not giving attention to reactor safety and of using outdated equipment, people still wonder whether such an accident could happen again elsewhere. Because there are several hundred reactors producing power in the world today, and because given enough time human error is almost inevitable, the answer has to be yes. About ten accidents have released radioactive particles during the past 34 years. Although the probability of a serious accident is very small at a particular site, the consequences may be great. Whether this poses an unacceptable risk to society is really not so much a scientific issue as a political one involving a question of values.

  Dead trees standing: a story about nuclear radiation

  What is it like to be in a place that has been subjected for years to radiation of the kind a nuclear power plant or its waste would release if a spill or operating accident occurred? I can tell you what it’s like because I worked as part of a team on a little-known, curious experiment conducted in the 1960s and ‘70s at Brookhaven National Laboratory on Long Island. There, scientists exposed a natural forest to radiation for 15 years to see what a nuclear war or the accidental or deliberate release of radioactive materials might do to one of nature’s ecosystems. The experiment was done because during the Cold War the danger of a nuclear war seemed real.

  So that scientists could work in the irradiated forest, the laboratory had moved the largest hunk of cesium-137 that could be safely handled by earthmoving machinery into the forest and mounted it on a vertical, movable pole that could be lowered into the ground and covered by lead shielding to protect the researchers, then raised up again automatically from a safe distance. We could work in the forest up to four hours a day because cesium’s radioactive isotope-137 was relatively “clean”—only gamma rays were produced. The result appears in Figure 5.6.

  Figure 5.6 The irradiated forest after about 10 years of exposure to intense radioactivity. (Top) From the air—the dead trees standing are visible and the bare ground beneath them. (Bottom) And near ground zero. (Top photo courtesy of Brookhaven National Laboratory; bottom photo by Daniel B. Botkin)

  Eight years after the radiation began, I entered the forest to do my day’s fieldwork, studying how the radiation was affecting the growth of trees. When all the trees are killed in an ordinary forest—say, by a disease, an insect outbreak, or a prolonged period of drought or of freezing temperatures—most of the trees soon fall over and decay. Mounds of rich organic humus, the product of that decay, are left, and soon tree seedlings and saplings sprout along with flowers and grasses adapted to open areas. Life begins anew among the dead.

  But that wasn’t the way Brookhaven National Laboratory’s irradiated forest looked that day. The strange thing was that although the trees had been dead for years, the forest looked as if it had burned just the day before. The trees were still standing, leafless, gray and brown, because the bacteria and fungi that decompose wood were killed, too, as were the insects and worms that help with decomposition. And nothing grew anew except in small triangles of “shade” where the dead trees standing protected small patches of ground from the radioactive cesium. Behind these trees, small but hardy sedges were about a foot or two high.

  A journey to the center of the forest—that is, to the source of radiation—after almost a decade of exposure was surreal. The forest was enclosed by two chain-link fences with locked gates. Just inside the fences, the woods were typical of those found on Long Island: a dense clutch of small pitch pines, scarlet and white oaks, and small shrubs, mostly blueberry and huckleberry. Many plants were quite fragrant. The sounds of crickets and cicadas filled the air. Ovenbirds called.

  My walk toward the source thus began as a pleasant stroll through the woods. As I moved closer to the center, more and more pine trees had dead branches and needles. Farther on, all the pines were dead, but many were still standing. Some of the fallen pine trunks were beginning to rot—the bacteria and fungi of decay at the distance from the cesium had survived the radiation.

  Up ahead, the white oaks looked sick. A bit farther on, the white oaks, too, were all dead and standing. The scarlet oaks proved to be the hardiest of the trees. As I neared the source, I saw some survivors.

  It was like walking up a mountain. The higher you climb, the smaller and fewer the trees. Eventually, the trees drop out completely and you reach a zone of low shrubs, then a tundra zone of smaller ground plants, and finally, if the mountain is high enough, no visible life at all.

  So it was in the irradiated forest. Blueberries and huckleberries survived the trees, growing among grasses and sedges. Closer to the source, only a patchy cover of sedges. Then you came upon perfect triangles of sedges, green, grasslike, flowering plants growing behind the trunks of standing dead trees. Just as they do with sunlight, the trunks shaded the sedges from the radiation. It was an eerie demonstration of how light rays travel.

  Near ground zero, all plants were dead, but they had not decayed. The radiation had killed off the armies of decay: fungus, bacteria, earthworms, and so forth. I hunted around for any signs of life. Within about six feet of the source, I found, on the back of a sign warning of the radiation danger, a small green patch of the algae Protococcus, which grows on damp soils. The sandy soil encircling the source was tinted gray, the color of the dead leaves and twigs that had not decayed.

  From the air, the forest was an eerily beautiful sight of death radiating outward. You could see the tower containing the radiation, surrounded by a lifeless gray-tan zone. Then came a circular ring of sedges, one of shrubs, another of oaks without pines, and then the healthy forest. Rather than the intricate mosaic of life-forms that characterizes normal forests, the pattern at Brookhaven was a series of concentric circles signifying the stages of death by radiation.

  The radioactive waste generated at nuclear power plants and the problems associated with the transportation and storage of nuclear wastes can create equally mournful landscapes. For this reason, the irradiated forest at Brookhaven National Laboratory should make us pause and think carefully before we move in the direction of greater emphasis on nuclear power rather than on energy sources that are more environmentally benign.

  For those who are interested: more background

  What is nuclear energy?

  For most of us, nuclear energy is exotic and strange, so it may be helpful to go over some of the basics here. Nuclear energy is the energy of the atomic nucleus, released by splitting atoms, a tricky business done inside what are called nuclear reactors. In the United States, almost all these reactors use a form of uranium oxide as fuel.

  Three types, or isotopes, of uranium occur in nature. Unfortunately, the one that is useful in conventional nuclear reactors—uranium-235—is relatively rare, making up about 0.7% of the uranium found on Earth. Most uranium—99.3% of all natural uranium—is uranium-238. The third type, also not used in conventional reactors, is uranium-234, which makes up about 0.005%. The first step in making useful uranium fuel is to concentrate uranium-235 from 0.7% to about 3%.

  Uranium atoms split naturally, releasing energy, nuclear fragments, and neutrons. The neutrons go out and split other uranium atoms. Here’s one of the tricky bits: If too much U-235 is brought together, lots of neutrons are produced, and there is a chain reaction that gets away. This is how an atomic bomb works, and in a reactor a runaway reaction can produce enough heat to melt the machinery and the building and emit dangerous radioactive material into the atmosphere and water. If the U-235 is not concentrated enough, not much happens, so the goal is to get just enough U-235 splitting and producing neutrons. This is done by finding a way to control the reactions: If things get going too fast, to take away the excess neutrons; if too slow, to let more neutrons fly around.

  Neutrons are controlled, or “moderated,” both to slow them down so they are more likely to split atoms and to control the rate of reactions. Most nuclear power plants use a combination of graphite rods and huge bathtubs of water to control and contain the reactions.
Water is a good absorber of the neutrons. An eerie thing to do is to visit a bathtub reactor where you can stand on an iron grating above a very deep pool of water, as I have done. You look down and see an intense blue glow where all that atomic reaction is going on. If you were down there where the blue light is, you’d be dead. It’s sort of like looking into the devil’s mouth, I thought, standing there.

  The energy from splitting uranium atoms is used to heat water and make steam, which then runs a steam turbine that generates electricity. Coal- and gas-fired electrical generators do the same thing, just using a different source of heat to boil water.

  There are three kinds of nuclear reactors—conventional, breeder, and fusion—and each has its own drawbacks:

  • Conventional: The fuel is limited; as I wrote earlier, there is only a 40-year supply or less for the world. Therefore, it is not a long-term solution.

  • Breeder: Bombs can be made from the fuels.