Nuclear Power

Part 1: The History of Nuclear Power

On a beach in Normandy, France, thousands of Americans died on June 6, 1944. The Allied Expeditionary Force landed there, launching the final offensive that ended the long war against Nazi Germany, a worldwide catastrophe that claimed over forty million lives before it ended.

Five hundred miles away another little known drama was to prove as important as the bloody landing at Normandy. It happened in the narrow straits separating Denmark from Sweden. On a beach in Normandy, France, thousands of Americans died on June 6, 1944.

The Allied Expeditionary Force landed there, launching the final offensive that ended the long war against Nazi Germany, a worldwide catastrophe that claimed over forty million lives before it ended. Five hundred miles away another little known drama was to prove as important as the bloody landing at Normandy. It happened in the narrow straits separating Denmark from Sweden.

To understand the full significance of this drama we need to go back a few decades and to meet a brilliant and kindly gentleman named Niels Bohr. During the 1920s and 1930s in his home town of Copenhagen, Denmark, Bohr was director of the world's most famous and productive center for studies of the atom. Many of the world's greatest scientists came here to study, to learn and to lay the foundations of what came to be called nuclear power. Bohr himself won the Nobel Prize in 1922 for his work in changing our picture of the atom. At that time, however, few realized the practicality, or the danger, of such power in peace or war.

In January of 1939 Bohr came to the United States to visit Albert Einstein at Princeton, New Jersey, and to attend a conference on theoretical physics in Washington, D.C. He brought with him startling news from Europe.

Lise Meitner, an outstanding Jewish physicist who had escaped Hitler's Third Reich, had recently told Bohr of some unusual new results her former colleagues Otto Hahn and Fritz Strassman were getting on experiments with the heavy element uranium. One radical interpretation of their new data led Meitner and others to believe uranium could fission! That is, the nucleus of the atom itself could split apart-something never before observed-and in the process release incredibly large amounts of energy!

Within days of Bohr's news, three groups in the United States quickly confirmed the Hahn Strassman data. Once confirmed, they immediately set to work feverishly to develop a theory to explain nuclear fission. And to develop a practical way to produce nuclear power.

Bohr predicted correctly that only one particular kind of uranium-the uranium 235 isotope would be capable of fission. But if enough of this rare isotope could somehow be obtained, theoretically at least, a bomb of almost unbelievable power could be built.

By the time Bohr returned to Denmark, World War II was heating up. Hitler attacked France and the low countries, occupying Denmark quickly in 1940. Bohr tried to keep his Institute open and do what he could to save fleeing Jews, as well as continue his own research in secrecy.

He was ignored for a few years of the occupation. Then in the fall of 1943 (just as the Normandy invasion was being planned) Bohr made a daring escape across the narrow channel into Sweden. From there he was ferried fn the gun turret of a bomber to England, almost dying from lack of oxygen during the flight.

By the winter of 1944 he was working with other world class physicists in top secret government laboratories in Los Alamos, New Mexico. Many of these physicists were, like himself, in exile from their native countries. Some of the most famous included Enrico Fermi (from Italy), Edward Teller and Leo Szilard (from Hungary) and Hans Bethe (from Germany). The laboratory was headed by a famous American physicist, Robert Oppenheimer. Together they witnessed the world's first nuclear explosion on July 16, 1945.

Let's back up a little again and see in more detail just what scientific and technical steps were taken by these scientists, engineers and workers to get to that historic moment. Here is the picture of the atom put together by Thomson, Rutherford, Bohr and others during the early years of the twentieth century.

Every piece of matter in the universe is made of tiny atoms. Each atom has a structure of its own.

In the center is an incredibly dense nucleus. This nucleus is made of a combination of two kinds of even smaller particles, protons and neutrons.

Most of the ordinary changes in our world are due to rearrangements of the electron clouds that buzz around that tiny nucleus.

The nucleus itself was supposed to be very stable, though the new work of Marie Curie and others had shown that for a few special kinds of atom, radium, for instance, the nuclear structure could change. It could be, they found, radioactive. That is, it could spontaneously disintegrate, changing itself into smaller atoms.

The startling news from Germany showed that in the case of uranium at least, if that nucleus was hit by a slow-moving neutron, it would split in two! And in that cracking, it would release an enormous amount of energy. Energy far greater than any known chemical change.

Not only did the U-235 nucleus give out enormous amounts of energy when it split, it also spit out at least two more neutrons. What if-the scientists asked-what if each of these newly created neutrons itself hit another uranium 235 atom? And what if these two split, and then the four split and the eight and sixteen and thirty-two ... etc., etc.! Each of these doublings would release double and double and double the energy! The result would be a chain reaction that could indeed release energy the likes of which the world had never before seen.

What could be done in theory was soon done in practice. The effort to actually make the first chain reaction happen was led by a refugee from Fascist Italy, Enrico Fermi. What Fermi and his co-workers did was construct the first "nuclear pile" in a squash court under the former football stadium at the University of Chicago. It was called a "pile" in order to disguise its actual intent, though in truth it was a "pile" of graphite blocks, alternated with uranium and uranium oxide blocks.

Since only slow-moving neutrons would cause the uranium nuclei to split, the idea was to let the graphite blocks slow down the neutrons that were being spontaneously emitted by the fissioning uranium. These slower neutrons would then hit more uranium nuclei, causing them to "fission." This would release more neutrons which would hit more nuclei and if you had the right amount of fuel close enough together-what was called a critical mass-a chain reaction would result.

It was critical in a nuclear reactor, as distinguished from a nuclear bomb, that the chain reaction be controlled. That is, it must not continue to multiply. To control it, Fermi's University of Chicago reactor had special cadmium control rods that could be raised and lowered to absorb neutrons, and thus adjust the number to a self-sustaining, but not a run-away, rate.

At 3:45 pm on Dec. 2, 1942 the nuclear pile at the University of Chicago did become self sustaining. A telegram from the physicist Arthur Compton said it all, "The Italian navigator has entered a new world." Yes, Enrico Fermi and his co-workers had entered a new world as revolutionary as the one that earlier Italian, Christopher Columbus, discovered some 450 years before.

Now that the new world had been discovered-in the middle of a world-wide struggle for survival against Nazi Germany, Fascist Italy and militaristic Japan-the race to produce a militarily effective bomb took precedence over all else.

Albert Einstein, long known for his pacifism, himself wrote a letter to President Roosevelt urging him to proceed with all due speed to develop an atomic bomb. Germany was now known to be working on such a bomb under the leadership of the famous physicist, Werner Heisenberg. Both sides guessed correctly that it was only a matter of time before it could be done. In the most stringent secrecy ever mounted in a free country, the United States did proceed with all due speed to construct gigantic research, development and production centers in Washington state, in New Mexico, and the largest of all, an entire new secret city in Oak Ridge, Tennessee.

At Oak Ridge over seventy-five thousand people were hired to build and operate the large factories designed to produce fission grade uranium that would be capable of making a nuclear bomb. Research had confirmed Bohrís prediction that it was only one particular isotope of uranium, U235, that was capable of fission. Since naturally occurring uranium contains less than one percent U-235, the task of separating the two isotopes was formidable, Several methods were tried. In the end the method that worked best was called gaseous diffusion.

Security at Oak Ridge was extremely tight. All persons entering the city had to have identification. All had to have their cars checked and sometimes their persons searched. Except for a very few of the top scientists and engineers, no one working at Oak Ridge was given any information about the overall goal of the project. Workers were warned to say nothing at all about their work. Not in letters, not in telephone calls, not in person-to-person talk. Similar measures were taken at the Washington and the Los Alamos sites.

A little over two and a half years after the first chain reaction at the University of Chicago, the world's first nuclear bomb was exploded at Alamagordo, New Mexico. Just one month later, two bombs (the only other two then in existence) were dropped on Hiroshima and Nagasaki, Japan. Both of these cities were destroyed. Over a hundred thousand Japanese citizens were killed. Japan surrendered and the most destructive war in human history was over.

Since that violent birth of the nuclear age, the science and the technology of nuclear power have advanced at a rapid pace worldwide. The United States had a monopoly in 1945 when the war ended, but very soon the Soviet Union and Great Britain (1949), France (1960), China (1964), and then India (1974), joined the nuclear nations in exploding their own nuclear bombs.

As for peacetime uses of nuclear energy, every major nation on earth has built and now operates nuclear power plants. In 1952, led by the physicist Edward Teller, the United States for the first time exploded a fusion bomb, called a hydrogen bomb, thousands of times more powerful than the first fission nuclear bomb. Again, other countries successfully built and tested their own fusion bombs.

In a speech on Dec. 7, 1953 (the 12th anniversary of the Japanese attack on Pearl Harbor) then President Dwight Eisenhower proposed a new direction-what he called "Atoms for Peace."

Many peaceful uses of nuclear energy were developed and are still being developed. In medicine especially, radioactive isotopes have become valuable tools both for diagnosis and for treatment of many diseases, including cancer. In biological and ecological studies, radioactive tracers are used to discover much new information about the workings of living systems.

During the 1950s and 1960s nuclear power plants multiplied as the need for energy worldwide began to soar. Beginning in the 1970s and continuing today, there is a growing a movement of dissent about nuclear power in peace as well as war.

Although the nuclear power industry can point with pride to a remarkable safety record-as yet no known citizen fatalities in this country due to nuclear power accidents or failures- risks do exist and critics are not silent.

Almost as soon as the first nuclear bombs exploded, many scientists directly involved in the research took leading roles in trying to alert the world to the dangers of nuclear war. And to the need for international control of these doomsday weapons.

In 1968 the United Nations passed a non-proliferation treaty designed to prevent the spread of nuclear weapon technology. In this treaty 188 nations agreed to allow all nations to develop peacetime nuclear power programs but prohibited the transfer of technology and materials needed to produce nuclear weapons. The treaty was not signed, however, by three nations that did have nuclear weapon capabilities, India, Pakistan and Israel. North Korea signed the treaty but then withdrew in 2003.

And in the early 21st century both North Korea and Iran are suspected of developing nuclear weapon capabilities in clear violation of the non-proliferation treaty.

Let's look at the current state of our knowledge and our controversies about nuclear power in Part 2.

Part 2: Nuclear Power, Today and Tomorrow

"Better active today, than radioactive tomorrow ... No nukes is good nukes."

"Nuclear power is the cleanest, safest and least expensive way to provide energy for our future."

"If we had 60 percent of our electricity coming from nuclear power and 20 percent from coal, the U.S. would easily comply with Kyoto," said Greenpeace co-founder Patrick Moore. "That's like taking 100 million cars off the road."

Who do you believe? What do you believe?

It's not easy. Especially in the present-day climate of heated debate. This is not going to tell you what to believe, nor even to suggest that there is one right way to believe. What it can do is tell you what is presently known about nuclear power. And it can briefly outline the confusing mix of values and facts that will determine the future of nuclear power.

First of all-just what is nuclear power? Notice I said nuclear power, not atomic power. Most of the sources of power in our world today-oil, coal, gas, wood, even human and animal muscle power-are atomic power. That is, they all get their energy from rearrangements of the electron shells in atoms. Nuclear power, however, gets it energy from a far more concentrated source by rearranging the particles in the nuclei of atoms. This is the same source of power that our sun, and all the other stars, use to produce light and heat.

We know today that the world is made of a little over one hundred different kinds of elements. Each element has a unique number. They go from element number one, hydrogen, all the way up to the last naturally occurring element, number 92, uranium. Beyond uranium scientists have now made in the laboratory still heavier elements, at this writing all the way up to number 106.

The atomic number tells how many positive charges the given atom has in its nucleus. This is the same as the number of proton particles. Hydrogen has the least possible number of protons, one. Uranium has the most naturally occurring number of protons, ninety-two. It turns out that nuclear power, for the most part, comes from rearranging the nuclei of either the heaviest or the lightest of the elements.

Let's start with the heaviest, uranium. When elements get that large, the nucleus tends to be unstable. It tends to break apart spontaneously. This spontaneous breaking apart is called "radioactivity."

When a heavy radioactive element, like uranium or radium, does break apart, it spits out a particle or particles from its nucleus and what is left is a different element. The particles and rays emitted in the change are packed with high energy. The new element formed from this change is often itself radioactive. In turn it spits out more particles and still another new element is formed, again, often radioactive. In this way what is called a radioactive decay series continues until we finally do reach an element like lead which is stable. At that point no further radioactivity occurs. In some cases the series of changes happens in a matter of seconds. In other cases it takes years, even hundreds of thousands of years to get to the stable state.

At each stage of the decay process, large amounts of energy are also given off. This is the same energy that was formerly used hold together the nucleus. Energy that can be calculated using Einstein's famous formula for the equivalence of energy and matter, E=mc2.

On earth, the number of atoms that are naturally radioactive is very small. Small in proportion, that is, to the total number of non-radioactive atoms. It may surprise you, though, to learn that in the air in an average living room or kitchen, there are at least ten or twenty billion radioactive atoms! This is not due to a nuclear weapon test, nor to a nuclear power plant. It is just the natural background radiation that so far as we know has been that way for millions of years past.

Let's move now into artificially created radioactivity, and into fission and fusion power.

Besides the spontaneous disintegration of many heavy atoms, physicists discovered just before the second World War that some few particular isotopes of elements could fission. (Isotopes are forms of an element that have the same number of protons, but differing numbers of neutrons in the nucleus.) Some of these isotopes of heavy elements break apart in a more radical way, splitting into two almost equal parts and giving out much more energy as well as two or more high-speed neutrons.

They also discovered that if they arranged these isotope-notably uranium-235 (92 protons and 143 neutrons)-into the right geometry, a chain reaction would result. One U-235, for instance, splits, giving off two neutrons and a lot of energy. These two neutrons each hit nearby U235 nuclei and cause them to split. Each of these gives off two apiece and you quickly-very quickly-get four, eight, sixteen, thirty-two, sixty-four, etc. etc. etc. And the reaction gets to very very high energy output.

If you arrange enough of the fissioning uranium in the right shape the chain reaction very quickly becomes an explosion. On the other hand, if you arrange them into another kind of shape, you can control the chain, and it does not explode. Instead it gives off a continuous supply of reliable heat that you can then use to boil water and run electrical generators. This is what happens in a nuclear power plant.

It needs to be emphasized that although the two cases are similar in some ways, they are totally different in others. Both rely on the energy from chain reactions of either uranium or the artificially created plutonium.

However, the construction being very different, there is no chance at all that a nuclear power plant could explode like a nuclear bomb. The high tolerances and the exposure to very difficult corrosion problems of pipes, valves and other equipment-as well as the potential for serious human operator error-do lead to the possibility for serious accidents however. Accidents in which dangerous amounts of radioactive elements could escape the reactor building and be spread by wind and water through nearby communities, causing serious harm to humans and other living things in the biosphere. Not only immediately but for years or even centuries to come. This is because one of the harmful effects of radiation can be genetic damage which is carried over into future generations.

The most serious nuclear power accident in the world happened at Chernobyl in the Soviet Union on April 26, 1986. Thirty-one workers at the power plant died in the accident. Over 100,000 people were evacuated from their homes in an eighteen mile radius around the plant. Radioactivity levels of soil, air and water in this area are still substantially above accepted safety levels so that many of these people will not be able to return for some years to come. In addition, radiation experts estimate there will probably be an additional one to two hundred deaths among the most severely exposed from radiation-caused cancer in the next few decades.

Since genetic effects take longer to observe, one can never be sure. So far the signs are hopeful. Especially since the results from studies done on the survivors of the much worse nuclear catastrophes at Hiroshima and Nagasaki, Japan, over forty years before, are now coming in. So far these studies show a surprising lack of genetic effects.

Radioactive materials from the Chernobyl meltdown were carried by winds over much of northern Europe, small amounts even reaching into the western hemisphere and the United States. There is some dispute among experts today, but the vast majority agree that so far there seem to have been no harmful effects in people, plants or animals from this fall-out radiation.

The most serious accident in this country was at Three Mile Island near Harrisburg, Pennsylvania in 1979. Fortunately there were no fatalities here, nor as yet any health effects to people living nearby. In fact the total amount of additional radioactivity in the near vicinity of Three Mile Island in the weeks immediately following the accident was not as great as you would get on one transatlantic airplane flight.

Experience from the accidents has also led to new designs and added safety features on new reactors that will make future accidents increasingly unlikely.

This is nuclear power from the fissioning of heavy atoms. There is also nuclear power from the fusing of very light atoms. One isotope of hydrogen, for example, has two extra neutrons in its nucleus. Under certain intense circumstances it can fuse together with another hydrogen to make helium, element number two. In this process even larger amounts of energy are given off than in fission. Hydrogen fusion is the basic source of energy that was tapped in the first hydrogen bombs. It is also the basic source of energy in the sun and stars.

Though a great deal of research and development has already been done, we still have not developed a practical way to tame the fusion reaction and to produce nuclear fusion power plants.

Many researchers think that once we do this-and few doubt that it will eventually be done-the world will move toward fusion nuclear power as its first energy choice of the future. Not only could it produce abundant and cheap energy, it could produce this energy with few, if any, of the disadvantages of fission plants. Fusion power plants, for instance, would have much more manageable waste problems. Unlike fission, the fusion reaction itself produces no radioactivity. Fusion reactions are so intensely powerful that great economies could be made in providing energy for the greatest number of people at the least cost.

Let's sum up now. There are two kinds of events that produce energy and power in our world.

One is atomic power. This is the kind of energy and power we get from rearranging the electron shells of atoms. The kind of power we get from burning wood, coal, oil, gas and gasoline. The kind of power we get from burning food in our own muscle cells.

The second kind is nuclear power. This is the kind of power we get when heavy atomic nuclei fission-that is, split apart. And the kind of power we get when light atomic nuclei fuse-that is, join together.

The United States in 1990 got over twenty percent of its electricity from nuclear power plants. Because of increasing public fear, no new nuclear power plants have been ordered in the United States for some years now. However in other countries nuclear power plants continue to be built and to provide an increasing proportion of the world's electricity.

Nuclear reactions can be used in an uncontrolled way to produce a nuclear explosion. They can also be controlled in a different kind of structure to produce electrical power. Nuclear reactions produce radiation that is potentially harmful to living tissues.

Radiation can also damage genes, and thus effect future generations. This same radiation, in appropriate doses, can also be used in many helpful ways. It can be and is used to help diagnose diseases, destroy cancer cells, trace toxic waste flows and help solve many thousands of baffling environmental and scientific problems.

The radiation produced by nuclear power consists of invisible high-speed particles and rays. Some radioactive elements produced by nuclear explosions and nuclear power plants are short lived, others are extremely long-lived. The most common measure of how long they will remain radioactive is called the half-life. A half-life of ten years means that in ten years half of the radiation will be gone. Ten years later you have only a fourth as much radiation. Etc. Etc. Half lives range from fractions of a second to hundreds, thousands or even millions of years.

With this background of history and fact, let's conclude with a brief look at the present-day debate about nuclear power's present and future.

Considering the dangers, one extreme view would be to attempt by education, legislation and public pressure and protests to totally shut down all nuclear power plants, all nuclear research and destroy all existing nuclear bombs. We should make all the world a nuclear-free zone. "No nukes is good nukes." If we cannot do this immediately, we should move in that direction as fast as humanly possible.

Considering the potential, the opposite view would be to rush full-scale into a more effective and accelerated nuclear power program in order to provide cheap energy for all the world's people, prevent acid rain, air pollution and catastrophic global warming. We should also accelerate development of new nuclear weapons technology so as to effectively deter war and promote human freedom. And if we cannot do all this immediately, the sooner the better.

No doubt most people today would find their own views somewhere in between these two extremes. To help you understand the extremes as well as the in-betweens, let's take a look at some of the reasoning behind both.

On the side of the dangers, we would have considerations like the following. The wastes from nuclear power plants and bomb factories is packed with intensely dangerous radiation. Biologists and geneticists tell us there is no lower limit to the danger to living things from radiation. Every little bit potentially hurts and can kill. We are producing radiation now that will last for thousands of years into the future. It is foolish to think humans can be trusted to keep anything in safe deposit for that length of time. We are bequeathing terrible time bombs to future generations.

An accident at a nuclear power plant (note Chernobyl and Three Mile Island) would be a far worse catastrophe than anything we have hitherto been faced with in human history. Thousands of people, maybe millions, would be exposed to dangerous radiation for years, for centuries to come. Not to mention other living things.

Worst of all would be a nuclear war which no one could win and which could bring about the destruction of the human race. Indeed the fatal poisoning of the planet itself for any kind of life. Getting rid of these potentially catastrophic power plants and these insanely destructive weapons once and for all is the only rational alternative to species suicide.

On the side of the potential we would have considerations like the following.

The nuclear industry-despite Three Mile Island and Chernobyl-has one of the best safety records of any industry ever created by human beings. There is no reason to suppose we cannot continue to improve our designs and our safeguards and to prevent catastrophes such as opponents imagine. We cannot choose to have no risks in this life. The wise person chooses the path with the most potential for good and the least risk for harm. That is the case with nuclear power.

There may be no lower absolutely safe limit of radiation, but few people realize that you get over a thousand times more radiation watching TV, or just living in a brick house than you would get living next door to a nuclear power plant. The accident at Three Mile Island caused radiation immediately surrounding the plant that was only a third of what you would get on a commercial jet flight from coast to coast.

Chernobyl was indeed worse, but even here many fewer people died or were hurt than in many hundreds of other accidents in recent years due to reliance on conventional sources of power such as coal, oil, and gas.

Contrary to critics, we already have quite a few safe and effective ways to dispose of radioactive wastes. And remember, a nuclear plant produces less radioactive waste in the air, soil, and water than a presently operated coal-fired plant. In addition, nuclear plants do not contribute to air pollution, acid rain or perhaps most important of all--to potential global warming.

Many scientists in the 21st century are warning that our ever-growing emissions of carbon dioxide from the burning of fossil fuels may lead to a disastrous warming of the planet. Many of these same scientists also think nuclear power is one of the best ways to prevent this warming.

It is true that a nuclear war would be a very great human catastrophe, perhaps even the ultimate human catastrophe. However, it is naive and self-defeating to imagine you can prevent this by total (and especially by unilateral) disarmament. Such a path would itself lead to the very highest risk of bringing on what you want to prevent.

The newspapers, the television specials, the books and pamphlets, are all bombarding us with information, rhetoric and reasoning on these issues. Take it on yourself to investigate as carefully and fairly as you can. Don't let slogans make up your mind. Study all sides of the issue and come to your own conclusion, like any other scientist would.