Following my lectures on nuclear power, I normally get several questions. I shall address a representative sample of them here.
Power Needs
| Q: | I understand that we have too many plants for generating electricity. Why, then, should we build more? |
| A: | In the early 1980s, we had too many, but that has changed. From 1982-1989, U.S. electricity consumption increased by 30%. Some sections of the nation are already experiencing blackouts and brownouts, and the frequency of these will increase if our consumption continues to rise. Insufficient electric power can stunt economic growth, and that can have many severe consequences on both our wealth and our health as long as our population is growing. |
| Q: | Won't solar energy be taking care of our electric power needs? |
| A: | While progress in developing photoelectric cells has been very encouraging, there is no prospect that they can provide a substantial fraction of our total electric power needs in the next 10-20 years. |
| Nuclear and solar power are not in competition, and probably never will be. Solar power cannot provide electricity at night. If we build nuclear power plants to provide night-time power, it would be economically irrational not to operate them during the day, since their fuel costs are very low. Solar power will therefore be useful only to provide the additional power needed during the day. This situation can change only if batteries for storing electricity become very much better and cheaper that those now available or under development. | |
Problems with Fossil Fuels
| Q: | How sure are we that the "greenhouse effect" is real? |
| A: | Whether or not the recent succession of warm temperatures and droughts is due to the greenhouse effect is uncertain. But there is no question that, if we continue on our course of burning fossil fuels, it will eventually become very real. The only question is when. If we wait until we find out, it will be too late to take steps to avert it. |
| Q: | How sure are we that acid rain is destroying forests and fish? |
| A: | The evidence is not certain, but the scientific consensus is that there are substantial adverse effects. The public perception here is also important. For example, the political tension acid rain causes between Canada and the United States makes it worth spending money to reduce the problem. Spending this money also reduces air pollution. |
| Q: | Can't we eliminate the air pollution from coal burning? |
| A: | It is quite easy to eliminate the visible smoke, which consists of the large particles, but these are not responsible for the adverse health effects. There is technology, albeit expensive, for greatly reducing the sulfur dioxide emissions, but it is not clear that this would greatly reduce the health impacts of air pollution (although it would reduce acid rain). The problem is that we don't know which of the thousands of components of air pollution cause the most severe health effects. If we don't know what to eliminate, we can't eliminate it. |
Radioactivity and Radiation
| Q: | Radioactivity can harm us by radiating us from sources outside our bodies, by being taken in with food or water, or by being inhaled into our lungs, but you seem to consider only one of these pathways. What about the others? |
| A: | All of these pathways are treated in the scientific literature, but in order to simplify popular expositions it is usual to treat only the most threatening pathway. |
| Q: | Cancers from radiation may take up to 50 years to develop, and genetic effects may not show up for a hundred years or more. How, then, can we say that there will be essentially no health effects from the Three Mile Island accident? |
| A: | We have determined the radiation doses in millirems received by these people. From many experiences with people exposed to radiation, like the Japanese A-bomb survivors and patients treated for medical purposes, we can estimate the effects of each millirem of radiation. A wide variety of scientific studies, including theoretical modeling and experiments on animals and on cells in laboratory dishes, contribute to this estimation process. |
| Q: | Measurements of radioactivity in air, for example, are made at a few monitoring stations. How do we know the levels may not be much higher at places where there are no monitoring stations? |
| A: | Scientists choose locations of monitoring stations so as to minimize this possibility, making use of the considerable body of scientific information on how materials are dispersed under various weather conditions. This information also predicts relationships between readings at various stations, which are checked to give added confidence. Radiation levels at different locations can be predicted from the quantity of radioactivity released and a knowledge of the weather conditions including wind speed and direction, and temperature versus height above ground. The weather conditions around nuclear plants are constantly monitored. Much can be learned about a radioactivity release from measuring radioactivity on the ground surface up to several days later. In the Three Mile Island accident, air samples were collected by airplanes to give additional data, and photographic film from area stores was purchased and developed to measure the fogging by radiation (no fogging was observed, but it would have been if there had been appreciable radiation). There are thus many independent ways to determine the pattern of radiation exposure, and they serve as checks on one another. |
| A: | This situation contrasts sharply with that for air pollution from coal burning. Since monitoring for air pollutants is much more difficult and expensive, there are very few monitoring stations even in a large metropolitan area. Nonetheless, air pollution kills many thousands of people every year and is thus a much greater threat to our health than is radioactivity from nuclear plants. |
| Q: | Radioactive materials can be concentrated by various biological organisms. For example, strontium-90 ingested by a cow mostly gets into its milk. Doesn't this make radioactivity much more dangerous than your calculations indicate? |
| A: | This is taken into account in all calculations and estimates. There was a widely publicized omission for the case of strontium-90 in milk in the 1950s, but that was a very long time ago, scientifically speaking. |
| Q: | Air pollution may kill people now, but radiation induces genetic effects that will damage future generations. How can we justify our enjoying the benefits of nuclear energy while future generations bear the suffering from it? |
| A: | Air pollution and chemicals released in coal burning also have genetic effects, as indicated by tests on microorganisms. While they are not as well understood and quantified, there is no reason to believe that the genetic impacts of coal burning are less severe than those of nuclear power. |
| The genetic impacts of radiation are not large. The total number of eventual genetic defects caused by a given radiation exposure added up over all future generations is less than half of the number of cancers it causes, less than one genetic defect for every 10 million millirem. | |
| There are many ways in which our technology injures future generations, such as consuming the world's limited mineral resources, which will cause them infinitely more serious injury than genetic effects of our radiation. In the latter case, we are more than compensating our progeny with biomedical research that will greatly improve their health in many ways, including averting much of their genetic disease. | |
| We leave future generations many legacies, both good and bad. The important point is that the good legacies outweigh the bad. | |
| Q: | Can the genetic effects of low-level radiation destroy the human race? |
| A: | No. The process of natural selection causes good mutations to be bred in and bad mutations to be bred out. In the very long term, mutations from any given amount of radiation exposure disappear if they are harmful, and are preserved if they are beneficial; they can therefore only improve the human race, although that effect is negligibly small. |
| Humankind has always been exposed to radiation from natural sources, hundreds of times higher in average intensity than low-level radiation from the nuclear industry. Yet even this natural radiation is responsible for only a few percent of all genetic disease. Spontaneous mutations are responsible for the great majority of it. | |
| Q: | Isn't the artificial radioactivity created by the nuclear industry, to which man has never been exposed until recently, more dangerous than the natural radiation which has always been present? |
| A: | The cancer and genetic effects of radiation are caused by a particle of radiation, say a gamma ray, knocking loose an electron from a certain molecule. In this process, there is no possible way, even in principle, for the electron or the molecule to "know" whether that gamma ray was originally emitted from a naturally radioactive atom, or from an atom that was made radioactive by nuclear technology. The answer to the question is NO. |
| Q: | Can radiation exposure to parents cause children to be born with two heads or other such deformities? |
| A: | NO. Such things are not occurring now although mankind has always been exposed to natural radiation. There is no possible way in which manmade radiation can cause problems that do not occur as a result of natural radiation. No new genetic diseases have been found among the Japanese A-bomb survivors or others exposed to high doses of radiation. |
| Q: | Is there any factual basis for radiation creating monsters like "The Incredible Hulk"? |
| A: | Absolutely none. These are strictly creations of an artist's imagination. |
| Q: | You frequently use statistics to support your case. But it is well known that, "while statistics don't lie, liars can use statistics." How can we trust your statistics? |
| A: | I make very little use of statistics, because there is no statistical evidence of harm to human health due to radiation from the nuclear industry. I use probabilities, which are something very different.* If you don't believe in probability, I would love to engage you in a game of coin flipping or dice rolling. Las Vegas, the various state lotteries, and insurance companies, are doing very well depending on the laws of probability. |
| One opponent of nuclear power has gotten lots of publicity by making flagrant use of statistics to deceive. If you look hard enough, you can always find an area around some nuclear plant that has a higher than average cancer rate. Of course, you can just as easily find one with a lower than average cancer rate, but he doesn't report that. | |
| Q: | How can you treat deaths due to radiation as statistics? These are human beings suffering and dying. |
| A: | There are also human beings suffering and dying from air pollution, from chemical poisons, from poverty, and so on. Nuclear power will reduce these problems. I am only interested in reducing the total number of people who suffer and die. |
| Q: | Isn't a nuclear accident that kills 1,000 people worse than having 10,000 people die one by one from air pollution with no one knowing why they died? |
| A: | I thoroughly disagree. The only reason anyone can believe such a thing is because the media handle it that way. They would give tremendous publicity to a nuclear accident killing a thousand people (or even a hundred people), but they hardly mention the 30,000 or so people who die from air pollution every year from coal-burning power plants. |
| If you would choose a technology that kills 10,000 per year with air pollution over one that kills 1,000 in a large accident each year, you should be given the job of explaining to the extra 9,000 victims (and their loved ones) that they must die because people don't like media reports of large accidents. I'm sure you would quickly change your mind. | |
| Q: | Does radiation make people glow in the dark? |
| A: | Radiation produces light only when extremely intense, as inside a nuclear reactor; people exposed to that much radiation would die instantly (as they would inside any other furnace). Comedians get laughs from jokes about irradiated people glowing in the dark, but there is no factual basis for that idea. |
| Q: | If we can't feel radiation, how do we know when we are being exposed? |
| A: | There are numerous instruments for detecting radiation. Many of them are quite cheap, reliable, and sensitive. It is very much easier to detect radiation than the dangerous components in air pollution. |
Trust and Faith
| Q: | Why should we believe scientists when they have made nuclear bombs and all sorts of devastating weapons? |
| A: | Working for the military is not an indication that a person does not tell the truth. Moreover, the scientists involved with nuclear power are an entirely different group (with a very few individual exceptions) than those who developed nuclear weapons. |
| I have never heard evidence that the scientific community as a group has deceived the public. Working as a scientist requires a high degree of honesty, if for no other reason than that dishonesty would be readily discovered and the career of an offender would be irreparably damaged by it. | |
| Q: | Since nuclear scientists rely on the nuclear industry for their livelihood, how can we believe them? |
| A: | University scientists do not rely on the nuclear industry; in fact most of them have lifetime job security guaranteed by the university that employs them (I am in that position). Radiation health scientists would get increased importance and job security if people decided that radiation is more dangerous, because they are the ones who protect the public from radiation. If the nuclear industry were to shut down today, they would have a secure lifetime career from participating in the retirement of plants. |
| On the other hand, the few scientists who have vocally opposed nuclear power make a good living out of their opposition. They get large fees for speaking and for testifying in legal suits, and their books have sold well. If a nuclear scientist were interested in making extra money, he would do well to reverse his position and become an opponent of nuclear power. | |
| A university nuclear scientist could become antinuclear without any repercussions on his job security. Scientists employed by organizations opposed to nuclear power, on the other hand, would instantly lose their jobs if they decided to become pro-nuclear. | |
| Q: | With nuclear scientists split on the question of dangers of radiation, how do we know which side to believe? |
| A: | The split in the scientific community is not "down the middle" as the media would have you believe, but is very heavily one-sided. All of the official committees of prestigious scientists, like the National Academy of Sciences Committee, the United Nations Scientific Committee, the International Commission on Radiological Protection, the U.S. National Council on Radiation Protection and Measurements, the British National Radiological Protection Board, and similar groups in other countries, agree on the effects of radiation (within a range of differences that is irrelevant for purposes of public concern), and they are backed by the vast majority of the involved scientific community of specialists in radiation health. There has not been even a single vote by a single scientist on these committees supporting the views of people like Sternglass or Gofman which have been widely trumpeted by the media. |
| Q: | Why should we trust the government when it gives us information on nuclear power? |
| A: | The scientific evidence on health impacts of radiation has little dependence on government sources of information. The same is true of most other areas covered in this book. You are mainly being asked to trust the international scientific community. |
| Q: | The nuclear "Establishment" told us that there could never be a reactor accident, but we had Three Mile Island. How can we trust them? |
| A: | The nuclear "Establishment" did not say that there could never be a reactor accident. The Reactor Safety Study, which represents the nuclear Establishment more than anything else on that issue, estimates that there is a 30% chance that we would have had a complete meltdown by now (between civilian and naval reactors), whereas there has been none. |
| Q: | How can we trust the nuclear Establishment when they construct nuclear power plants on earthquake faults? |
| A: | The regulations on location of reactors relative to earthquake faults are very lengthy, complex, and technical. They have been worked out by some of the nation's foremost earthquake scientists. The distance from a fault allowed depends on the type of fault and the length of time since it has been active. Contrary to widely circulated stories, there is no reactor constructed on top of a fault or even within a mile of one. |
| Earthquake scientists continue to do research on the matter. For example, after the severe 1989 earthquake in Armenia, they visited and carried out extensive investigations on the response of various structures. Small earthquakes, like the one near San Francisco in 1989, are of no consequence to nuclear plants. | |
| Q: | How can we trust reactor operators to do their job properly? How do we know they won't get drunk and cause an accident? |
| A: | In safety analyses, it is not assumed that reactor operators are perfect; it is rather assumed that they make mistakes just like anyone else — pushing wrong buttons, failing to do required jobs, and the like. In accordance with the principle of defense in depth, the guiding philosophy in power plant design, there are back-up systems to compensate for such errors. The failure of any one link, of course, reduces the effectiveness of the defense in depth. It is therefore avoided as much as possible. Reactor operators must frequently pass stiff examinations; there are several operators as well as a graduate engineer on hand at all times; there are training programs, supervision, and inspections. But it is clearly recognized by all concerned that reactor operators are human beings and must be expected to behave as other human beings, which is a long way from perfect. |
| Q: | How can we trust utilities not to take short-cuts in efforts to save money, thereby compromising safety? |
| A: | Since I have no first-hand experience with utility construction practices, I cannot speak as an expert on this. But utilities are guaranteed a reasonable profit by their public utility commissions if they behave properly. They therefore have no great incentive to save money by cutting corners. Moreover, an accident in a nuclear plant is perhaps the most serious business blow a utility can suffer, costing its stockholders hundreds of millions or even billions of dollars. The utility that owns the Three Mile Island plant almost went bankrupt as a result of that accident. |
| In addition, the Nuclear Regulatory Commission (NRC) makes regular inspections. Anything not properly constructed may have to be torn out and reconstructed, at very great expense. A completed plant near Cincinnati had to be abandoned because it did not have documentation to prove that all welds had been properly inspected. | |
| There is therefore a heavy incentive for utilities to behave properly in constructing plants. Similar considerations apply to operating plants. They are inspected frequently by the NRC, and heavy fines are levied for substandard practices. There are also careful inspections by the Institute for Nuclear Power Operations. This is an Atlanta-based organization sponsored by the nuclear industry because it recognizes that an accident in one plant causes difficulties for the whole industry. | |
Reactor Accidents and Safety
| Q: | Can a reactor explode like a nuclear bomb? |
| A: | No, this would be impossible. A bomb requires fuel with more than 50% Uranium-235, whereas reactor fuel has only 3% Uranium-235. A bomb cannot work if the fuel is intermixed with water because the water slows down the neutrons, but the fuel in a nuclear power reactor is immersed in water. There are other reasons in addition that make a nuclear explosion impossible. |
| Q: | Was the Three Mile Island accident a "close call" to disaster? |
| A: | All studies agree that it was not, because there was no threat to the integrity of the containment. |
| Q: | Could the Chernobyl accident happen here? |
| A: | NO. The Chernobyl reactor was of an entirely different type than U.S. nuclear power reactors, and it had several features that made it much less safe. |
| Q: | Is nuclear power safe? |
| A: | Nothing in this world is perfectly safe. But in comparison with other methods available for generating electricity, or with the risks of doing without electricity, the dangers of nuclear power are very small. They are also hundreds of times smaller than many other risks we constantly live with and pay no attention to. |
| Q: | Nuclear power is very new and different. How do you know that new and unsuspected problems will not develop? |
| A: | There has been a tremendous research effort on areas of potential trouble, and commercial reactors have been operating for over 30 years. The U.S. Navy has been operating a large number of very similar reactors for about 30 years. But, of course, new and unsuspected problems have developed and probably will continue to develop as in any technology. That is why there are continuing research efforts, many avenues for information exchange among plants, and continued attention to the problems by the NRC. I see no reason to believe that we cannot keep ahead of the problems and maintain the present level of safety. As experience accumulates, we learn more about safety problems, thereby improving safety. Many valuable lessons were learned from the Three Mile Island accident. The new generation of reactors has benefitted from all of this research and experience, and will thereby provide a 1,000-fold improvement in safety. |
| Q: | How can you trust the "fault tree analysis" method used in the Reactor Safety Study and other probabilistic risk analyses? |
| A: | It is the best method available. If you don't trust it, you can fall back on experience. If its results were overoptimistic, we would have had more close calls by now than have actually been experienced. These analyses have been carried out independently by several different groups, including some in other countries, with similar results always being obtained. Of course, probabilistic risk analysis is an active area of science, with new ideas constantly being injected to improve the process. |
| Q: | If reactors are so safe, why don't home owners' insurance policies cover reactor accidents? Doesn't this mean that insurance companies have no confidence in them? |
| A: | Insurance companies do insure reactors. In fact, they stand to lose more money from a nuclear accident than from any other readily conceivable mishap. However, they are limited by law in the amount they can insure against any one event, because if an insurance company were to fail, many innocent policy holders would be left without protection. |
| Liability insurance for reactors is covered by an act of Congress which provides over $7 billion of no-fault insurance on each plant, paid for by the utilities. Because of this insurance, coverage in home owners' insurance would provide double coverage and is therefore excluded. If the liabilities from an accident should exceed the maximum, Congress has stipulated that it will provide relief as is customary in disaster situations. Few other disasters are covered by as much private insurance. For example, there is little or no coverage for dam failures or bridge collapses. | |
| Q: | If reactors are safe, why are there evacuation plans for areas around them? |
| A: | This is an example of regulatory ratcheting by the Nuclear Regulatory Commission. Until 1980, there were no such plans, and they are not used in other countries. There are no evacuation plans around chemical plants, although evacuations in their vicinity are more likely to be necessary than around nuclear plants. Most evacuations occur as a result of railroad or truck accidents involving toxic chemicals, but there is no advanced planning for them. It would be difficult to dispute the NRC viewpoint that having evacuation plans increases safety to some extent. They gave no consideration to the fact that the existence and advertising of these plans is unsettling to the public. |
Radioactive Waste
| Q: | What are we going to do with the radioactive waste? |
| A: | We are going to convert it into rocks, and put it in the natural habitat of rocks, deep underground. |
| Q: | How do we know it will be safe? |
| A: | We know a great deal about how rocks behave, and there is every reason to believe that waste converted to rock will behave the same. Calculations on that basis show that buried waste will be extremely safe. For example, it will do thousands of times less harm to public health than wastes from coal burning. |
| Q: | If it's so easy, why aren't we burying waste now? |
| A: | Research is being done to determine the optimal burial technology. There are important political reasons for doing this research before proceeding. |
| From an objective viewpoint, there need be no rush to bury the waste, and in fact there would be important advantages in storing it for 50-100 years before burial — 70-90% of the radioactivity and heat generation would decay away during this time period. However, because of the intense pressure generated by public misunderstanding, the U.S. government is forging ahead with plans to begin burying waste shortly after the turn of the century. | |
| Q: | Isn't disposal of radioactive waste an "unsolved problem"? |
| A: | What is a solved problem? Some of the wastes from coal burning, better known as "air pollution," are simply spewed out into the air where they kill tens of thousands of Americans every year. Is that a solved problem? The solid wastes from coal burning are dumped in shallow landfills where, over the next hundred thousand years or so, they will kill many more thousands (see Chapter 11). Is this a solved problem? |
| We know many satisfactory solutions to the radioactive waste burial problem and are involved in deciding which of these is best. Any one of them would be thousands of times less damaging to health than our handling of wastes from coal burning. | |
| Q: | How long will the radioactive waste be hazardous? |
| A: | It will lose 98% of its toxicity after about 200 years, by which time it will be no more toxic than some natural minerals in the ground. It will lose 99% of its remaining toxicity over the next 30,000 years, but it will still retain some toxicity for millions of years. |
| This situation is much more favorable than for some toxic chemical agents like mercury, arsenic, and cadmium, which retain their toxicity undiminished forever. | |
| Q: | How will we get rid of reactors when their useful life is over? |
| A: | Fuel, which contains nearly all of the radioactivity, is removed every year. When a reactor is retired, the remaining fuel will be similarly removed and sent away for disposal as high-level waste. The residual equipment, which is only weakly radioactive, becomes low-level waste. Studies show that paying for this process adds less than 1% to the cost of electricity. The first commercial nuclear reactor at Shippingport, Pennsylvania, was disassembled and removed for $99 million, leaving the land available for unrestricted use. |
Miscellaneous Topics
| Q: | How long will our uranium supplies last? |
| A: | With present reactors, we can continue building plants for about another 30 years and still be able to guarantee each a lifetime supply of fuel. Beyond that we will have to convert over to breeder reactors. With that technology, our fuel supply will last forever without affecting the price of electricity (see Chapter 13). |
| Q: | Is nuclear power necessary? |
| A: | The United States could get along for the foreseeable future with coal. It would be more expensive as well as much more harmful to our health and to the environment, but we could get by. For other countries, the situation is much less favorable. Western Europe and Japan have relatively little coal, and will therefore sorely need nuclear power when the oil runs out or is withdrawn for political or economic reasons. For them, nuclear power is much cheaper than any other alternatives. |
| Q: | What harm could terrorists do if they took control of a nuclear power plant? |
| A: | In principle, they could cause a very bad accident, thereby killing tens of thousands of people, including themselves. However, nearly all of their victims would suffer no immediate effects, but rather would die of cancer 10 to 50 years later. In view of the high normal incidence of cancer, these excess cases would be unnoticeable (see Chapter 6). This would hardly serve the purposes of terrorist. |
| By contrast, there are many simple ways these terrorists could kill at least as many people immediately. For example, they could put a poison gas into the ventilation system of a large building. Other examples are given in Chapter 13. | |
| Nuclear power plants have very elaborate security measures with over a dozen armed guards on duty at all times, electronic aids for detecting intruders, emergency procedures, radio communication, and so on. To sabotage a nuclear plant effectively would require a considerable amount of technical knowledge, and a substantial quantity of explosives. | |
| Q: | Can reactors be converted into weapon factories? |
| A: | If a reprocessing plant is available, the plutonium in power reactors is usable for weapons but is of very poor quality for that purpose (see Chapter 13). Under nearly all circumstances, a nation desiring nuclear weapons would find it much cheaper, faster, and easier to produce the plutonium in other ways. This would also give their bombs higher explosive power and much improved reliability. |
| Q: | Could terrorists steal nuclear materials and use them to make a nuclear bomb? |
| A: | There is no material in the present U.S. nuclear power industry that can be used for making nuclear bombs. If we should do reprocessing of nuclear fuel, plutonium would be separated. But there would be many very formidable problems faced by terrorists in trying to steal it and use it to make a bomb (see Chapter 13), and their bomb would be a small one, capable of destroying about one city block. Terrorists could do much more harm much more easily by using more conventional means. |
| Q: | Why did the U.S. Government develop nuclear energy while ignoring solar energy? |
| A: | All objective analyses done during the 1950s and 1960s indicated that generating electricity from nuclear energy should be several times cheaper than generating it from solar energy. Moreover, solar energy is available only when the sun shines, which greatly increases the problems and the costs if it is used as a major power source. |
| No one, at that time, could foresee the political opposition to nuclear power which has driven its cost so high in the United States. | |
| Q: | Is the cost of waste disposal and the cost of eventually decommissioning**the plant included in the cost estimates for nuclear power? |
| A: | The cost of waste disposal represents only about 1% of the cost of nuclear electricity. A tax to cover this cost (with something to spare) is included in the consumer's electric bill, increasing it by about 1%. The cost of decommissioning is to be borne by the utility, so they include it in their calculation of the rate to charge customers. It contributes less than 1% to that rate. |
| Q: | Your discussion is too technical for us to understand. How can you expect a nonscientist to follow your arguments? |
| A: | I have done my best to make my arguments as understandable as possible. The one thing it is impossible to do, however, is to answer the criticisms of nuclear power without giving quantitative demonstrations of nuclear versus alternative technologies. Doing anything less than that, I could easily make any technology appear to be as dangerous, or as safe, as I choose. |
| If you are not willing to follow those quantitative demonstrations, you could just accept the results with the understanding that they have been accepted by the great majority of the scientific community. These results are stated most succinctly in Chapter 8 (results from opponents of nuclear power in parentheses): having all of our electricity generated by nuclear power plants would reduce our life expectancy by less than 1 hour (1.5 days), making it as dangerous as a regular smoker smoking one extra cigarette every 15 years (3 months), as an overweight person increasing his weight by 0.012 ounces (0.8 ounces), or as raising the U.S. highway speed limit from 55 to 55.006 (55.4) miles per hour, and it is 2,000 times (30 times) less risky than switching from midsize to small cars. | |
*To illustrate the difference between probability and statistics, consider the honest flipping of a coin. The probability for heads is 50%. If one flips a coin ten times and gets eight heads, he could say that his statistics indicate that heads comes up 80% of the time.
**Decommissioning refers to taking a plant out of service, dismantling it, and restoring the site for other uses.