Nuclear Reactors
Today I thought that you would like to hear about Nuclear Reactors and how they work, as well as some of their problems. It seemed that almost everyone was interested in this subject when I mention something about it on occasions, and the subject is a little bit different than High Finance.
There are currently 104 licensed to operate nuclear power plants in the United States (69 PWRs and 35 BWRs), which generate about 20% of our nation's electrical use. There are 439 nuclear power plants throughout the world today. They produce between 12 to 15 percent of the world’s electricity.
Many poor countries simply have no access to nuclear power, because of the high costs of building a nuclear power plant, the complicated technology involved, or political restraints on nuclear material that can be used both for a power plant and nuclear weapons.
Some rich European countries like Switzerland or the Netherlands use none or very little nuclear power because of its unpopularity and the availability of cheap renewable energy from other sources. Others, like Germany or the United Kingdome, rely partially on nuclear power, but have not built any new plants for decades. Nuclear power still produces only a small fraction of the electricity in countries were coal is still king, like China and India.
The global nuclear leader is France, with nuclear producing nearly 80 percent of the country’s electricity. France also exports huge amounts of nuclear power to European neighbors, and its energy conglomerate, Areva, builds most of the nuclear power plants worldwide.
First, we should talk a little about the fuel that makes reactors operate, and that is uranium. The process depends upon the fission process, and there are only four atoms that will undergo fission, at least as far as they know today. They are uranium, plutonium, protactinium, and thorium. The process of fission is splitting the nucleus of an atom into two nuclei, which is caused by the capture of a bombarding neutron. Each of the newly-formed nuclei is roughly half the mass of the former nucleus. It is accomplished by the emission of additional neutrons and a large amount of energy, and therefore is self propagating under suitable conditions. They chose uranium over the other three elements as a nuclear fuel because it more abundant safer to use, as well as other factors.
Where does this nuclear energy comes from? There four basic forces in nature. The weakest and most familiar is the gravitational force, which is an attractive force that varies inversely as the square of the distance between any two masses. This force is what holds us to the surface of the earth and holds our planets in position in rotating about the sun. Two golf balls also are attracted to each other, but there mass is so small that the gravitational attractive force to draw them together is imperceptible as compared to the mass of the earth which draws both golf balls to the earth. A much stronger force is the electromagnetic force, which varies as the square of the distance between bodies, and may be either attractive or repulsive. Now, if the two golf balls were magnets, they would be drawn together immediately. The two other forces exist only at the subatomic level. The weak nuclear force is associated with the decay of subatomic particles, and has an intermediate strength between the gravitation and electromagnetic forces. The strong nuclear force that is associated with the glue or bond that holds the nuclei of atoms together along with its orbiting electrons is the strongest force that is known in nature. This is a force that is similar to the gravitational force which holds the electrons spinning around the nucleus and keeps the electrons from spinning off into space. This is the force from where nuclear energy comes from, if it can be tapped. The value of this energy was given by Einstein in his formula E = mc2. To get some idea of how much this energy is, c is the speed of light which is 186,000 miles per second which is squared. To get this into some kind of comparable units, multiply this by 5,280 feet per mile, and this by 144 inches per foot, and this by 2.54 centimeters per inch, and finally squaring it, will give an amount of 129x1021. Multiply this quantity by the mass of the electron, which is extremely small, lets say it is one billionth the mass of a golf ball. This will give a number of 129x1012, which says that energy in this force is approximately 129 trillion times more powerful than that of gravity that is acting on that golf ball. Kind of impressive. During the fission process, this force is broken when the atom splits up, and releases this force in the form of nuclear energy.
Uranium as it is dug out of the earth is useless as a nuclear fuel. This because natural uranium consists of several isotopes, and the only one of these isotopes that is fissionable is Uranium235. So, what is an isotope? If you remember your chemistry, an atom consists of a nucleus that has one or more protons and one or more neutrons, with one or more electrons that revolve in orbits around the nucleus. For any atom, there is as many electrons orbiting around the nucleus as there are protons in the nucleus. The number of neutrons in the nucleus can vary. The two major isotopes in natural uranium is U238 which consists of 99.28305%, and uranium U235 which consists of 0.7110%.
Uranium occurs naturally in the earth as Uranium Oxide, U3O8. It is nonradioactive, which can be handled by most any means. It is commonly known as yellow cake. Pure uranium is radioactive, and it should be avoided in this form at all possible. Uranium is not as rare as once thought, and is now considered more plentiful than mercury, antimony, silver, or cadmium. It occurs in numerous minerals. The two major isotopes in natural uranium in deposits that are dug out of the earth, are uranium 235 and uranium 238. The only difference between the two is that U238 has three more neutrons than U235. In most all uranium fields, uranium amounts to about 1% of the soil that is excavated. Of the amount of uranium retrieved, only 0.7110% is uranium 235, which is the isotope that is useful in nuclear reactors and weapons. All the rest is primarily uranium 238.
Normally, for most chemical elements, the elements can be separated from each other because every element has separate properties from all other elements, such as by boiling off elements at different temperatures, combing chemically with other elements, dissolving in some kind of solution, etc. This can not be done with isotopes, because they all have the same properties. So, in order to separate them they must go through an isotope separation process.
For uranium, the uranium oxide that is obtained from the mine is sent to a chemical plant which transforms the uranium oxide into uranium hexafluoride. Natural uranium doesn’t vaporize until it has reached a temperature of about 3,800oF, making it almost impossible to separate its isotopes. Uranium hexafluoride has a vaporizing point of 148oF or 64.5oC, which now makes it possible to separate the two isotopes. The product from this plant is sent to isotope separation facility where it is separated by means of either by diffusion or centrifugation. It is primarily separated by means of centrifugation now. There are only three such plants in the United States. They are located in Tennessee, Kentucky, and Illinois. These plants are huge buildings which include long rows of centrifuges in which uranium is passed through from one centrifuge to the next centrifuge, until the desired enrichment is obtained, which is about 93% U235, and the rest is U238. There are several more enrichment plants now throughout the world. The number of centrifuges that uranium goes through is about 2,000 centrifuges, depending on how enriched the uranium needs to be.
After enrichment is completed, the finished product is sent to another chemical plant for converting the uranium hexafluoride into uranium dioxide UO2, which is also nonradioactive. After conversion, it is then sent to another plant where it is made into fuel rods for nuclear reactors. Now this is the grade of the fuel that the United States is selling to the rest of the world for about $100 to $125 a pound, or about $8 an ounce.
In comparison to all this, gold is selling for about $900.00 an ounce. It doesn’t take much more work to obtain gold from a gold field than uranium from a uranium field, and gold does not have to be processed any further after processing it in a mine. There seems to be a great disparity here somewhere. I asked the Atomic Energy Commission back in the 1960”s if I could get a cost greakdown for making Reactor-grade uranium. I was told very politely to forget it. Since I was under Top-Secrete Clearance classification, so I have said nothing for the past 50 years. I would guess that is long enough for this information to become declassified.
And now, how the reactor works. The uranium is placed into zirconium-steel rods which are placed into the Nuclear Reactor, which is large steel container in the shape of an giant egg with walls of about 8 inches of solid steel. It is about 20 feet high. The reactor sits inside of a large building, called the Containment Building, which is suppose to protect everyone that is outside the building. Should there ever be an accident, the Containment building should contain anything that should happen so as not to contaminate anything on the outside. Along with the fuel rods, there are also control rods which are placed inside the reactor, which controls the activity of the fission process so as not to get out of control. Surrounding all the rods inside the reactor is water which is converted into steam under high pressure from the heat that is generated from the fission process. This high-pressure steam is forced through pipes to a steam turbine which turns the axle at high speed. The axle is connected to axle of an electric generator which generates electricity. The electricity that is generated is transported by copper bus bars to transformers outside the reactor building which converts the voltage to a voltage of about 300,000 volts. This electricity is then transported by high-voltage transmission-towers to all parts of the country where it is used for electrical power.
All these processes creates waste material. The high-pressure steam that was used to drive the turbines is useless after it leaves the turbine, so it must be disposed of somehow. So, this steam is piped over into giant cooling towers where it is sucked up through the towers and condensed back into water or blown off in a cloud of moisture. Now, we have gotten rid of most of the steam, but what happens to all the heat that was created by all of this. Unfortunately, it is all just wasted by blowing it into the atmosphere. Now this heat has to be absorbed by something, it just doesn’t disappear. We have the same problem with disposing of heat from all the internal-combustion engines that are running all over the world such as from billions of automobiles, air-conditioning units, motors of all kinds, trillions or electric light bulbs, etc. I wonder if anyone has calculated the amount of Btu’s that are generated every second all over the earth that is wasted like this. I doubt it very much. So what is a good absorber of such heat? How about glaciers, that should work. Has anyone researched this? I doubt that also.
Now what happens to all the U238 isotopes which had been discarded in the process of separating out the U235 isotope. The last time I visited one of the Uranium Separation Plants, I asked why all the 50-gallon barrels were tossed along side all the roads throughout the plant. They told me that they contained all the U238 isotopes that were separated from the separation process, and which was apparently useless. I asked them why there were sitting there and not just dispose it back into the earth. They said that they had hopes of being able to convert them into the U235 isotope someday. I don’t know whatever happened to them, but at the rate they were creating the barrels they must have run out of room by now. To my knowledge, no one has figured out how to convert the U238 isotope into an U235 isotope. All you have to do is just remove three neutrons from the U238 isotope, and you will have U235. Simple! Just how do you do it?
All nuclear reactors create plutonium. When the fission process began in the nuclear reactor, there was no plutonium. But during the process, plutonium was created. How this was done was the fission process requires the bombarding the U235 isotopes with neutrons, and when one of the isotopes catches one neutron, the fission process begins and from then on it is self propagating. In the process of fission, the isotope splits apart, creating minor atoms, much radiation, and tosses out neutrons, protons, and electrons in all directions. These tossed out neutrons are the ones that bombard the U235 isotopes nearby, which in turn go into fission, etc. Along with the U235 isotope, there is some U238 isotopes mingled in with the mixture. Now the U238 isotope will grab one of these neutron also, which now turns into a U239 isotope, which there is no such thing, and becomes an unbalanced isotope. It quickly grabs an electron and a proton which there are also an abundant supply of them from the fission process, and you have Plutonium 239.
As almost everyone knows, the Energy Commission is building a disposal site for nuclear waste inside Yucca Mountain in Nevada. This project has been under design and construction for about 20 years. This is suppose to be the solution for the disposal of nuclear waste for a century or so.
One might ask, “How do the spent fuel rods get from say a reactor in Florida to the disposal site in Nevada?” It takes about 4 feet of concrete, or about 2 feet of lead, to protect anyone from being exposed to radiation. So if one would ship these rods in a cube, the cube must have 4 feet of concrete on all 6 sides. That makes a cube 8 feet on all its sides. However, this doesn’t leave any room for placing fuel rods into it. So, if the we left a hollow of say 2-feet by 2-feet by 10 feet long, that would make a block of 10 feet by 10 feet by 18 feet long, which weighs about 100 tons. The block is already too wide to ship on either the highways or by rail. So, how do they ship it? I would guess by rail and lowering the protection that is necessary. So, some day your were stopped at a grade crossing, and freight train passed in front of you carrying such a cargo, you would get sapped. How much, probably not too much for just a one time occurrence, but for those who live or work along side of such a rail line may get sapped quite often.
The nuclear waste that we are talking about mostly consists of Plutonium. Plutonium is the most toxic, most poisonous, most radioactive substance on the face of the earth. It has a half-life of 24,360 years, so it will be with us like forever. Plutonium does not occur in nature, it is only made by mankind. With all the hundreds of reactors around the world turning out plutonium at a rate of hundreds of tons a year, we are polluting the earth with the most deadly substance that is known to mankind. The pollution that mankind is creating from hydrocarbons and other substances is only a minor problem compared to the pollution that is being created by plutonium.
Radioactive wastes are waste types containing radioactive chemical elements that do not have a practical purpose. They are sometimes the products of nuclear processes, such as nuclear fission. However, industries not directly connected to the nuclear industry can produce large quantities of radioactive waste. It has been estimated, for instance, that the past 20 years the oil-producing endeavors of the United States have accumulated eight million tons of radioactive wastes. The majority of radioactive waste is "low-level waste", meaning it contains low levels of radioactivity per mass or volume. This type of waste often consists of used protective clothing, which is only slightly contaminated but still dangerous in case of radioactive contamination of a human body through ingestion, inhalation, absorption, or injection. In the United States alone, the Department of Energy states that there are "millions of gallons of radioactive waste" as well as "thousands of tons of spent nuclear fuel and material" and also "huge quantities of contaminated soil and water". Despite these copious quantities of waste, the DOE has a goal of cleaning all presently contaminated sites successfully by 2025. The Fernald, Ohio site for example had "31 million pounds of uranium product", "2.5 billion pounds of waste", "2.75 million cubic yards of contaminated soil and debris", and a "223 acre portion of the underlying Great Miami Aquifer had uranium levels above drinking standards". The United States currently has at least 108 sites it currently designates as areas that are contaminated and unusable, sometimes many thousands of acres The Department of Energy wishes to try and clean or mitigate many or all radiation waste by 2025, however the task can be difficult and it acknowledges that some will never be completely remediated. Just in one of these 108 larger designations, Oak Ridge National Laboratory, there were for example at least 167 known contaminant release sites in one of the three subdivisions of the 37,000-acre site. Some of the U.S. sites were smaller in nature, however, and cleanup issues were simpler to address, and the Department of Energy has successfully completed cleanup, or at least closure, of several sites.
The issue of disposal methods for nuclear waste was one of the most pressing current problems the international nuclear industry faced when trying to establish a long term energy production plan, yet there was hope it could be safely solved. A recent research report on the Nuclear Industry perspective of the current state of scientific knowledge in predicting the extent that waste would find its way from the deep burial facility - back to soil and drinking water (such that it presents a direct threat to the health of human beings - as well as to other forms of life) is presented in a document from theThe International Atomic Energy Agency which was published in October 2007 This document states "The capacity to model all the effects involved in the dissolution of the waste form, in conditions similar to the disposal site, is the final goal of all the research undertaken by many research groups over many years. As we will see in this report, this kind of investigation is far from being finished". In the United States, the Department of Energy acknowledges much progress in addressing the waste problems of the industry, and successful remediation of some contaminated sites, yet also major uncertainties and sometimes complications and setbacks in handling the issue properly, cost effectively, and in the projected time frame. In other countries with lower ability or will to maintain environmental integrity the issue would be even more problematic.
The spent fuel rods from a nuclear reactor are the most radioactive of all nuclear wastes. When all the radiation given off by nuclear waste is tallied, the fuel rods give off 99% of it, in spite of having relatively small volume. There is, as of now, no permanent storage site of spent fuel rods. Temporary storage is being used while a permanent site is searched for and prepared, which the United States has been searching for for the past 20+ years.
When the spent fuel rods are removed from the reactor core, they are extremely hot and must be cooled down. Most nuclear power plants have a temporary storage pool next to the reactor. The spent rods are placed in the pool, where they can cool down. The pool is not filled with ordinary water but with boric acid, which helps to absorb some of the radiation given off by the radioactive nuclei inside the spent rods. The spent fuel rods are supposed to stay in the pool for only about 6 months, but, because there is no permanent storage site, they often stay there for years. Many power plants have had to enlarge their pools to make room for more rods. As pools fill, there are major problems. If the rods are placed too close together, the remaining nuclear fuel could go critical, starting a nuclear chain reaction. Thus, the rods must be monitored and it is very important that the pools do not become too crowded. Also, as an additional safety measure, neutron-absorbing materials similar to those used in control rods are placed amongst the fuel rods. Permanent disposal of the spent fuel is becoming more important as the pools become more and more crowded.
Decommissioning nuclear facilities will also create large amounts of radioactive
wastes. Many of the world's nuclear sites will require monitoring and protection
for centuries after they are closed down.
The global volume of spent fuel was
220,000 tonnes in the year 2000, and is growing by approximately 10,000 tonnes
annually. Despite billion of dollars of investment in various disposal options,
the nuclear industry and governments have failed to come up with a feasible and
sustainable solution.
Most of the current proposals for dealing with highly radioactive nuclear waste
involve burying it in deep underground sites. Whether the storage containers,
the store itself, or the surrounding rocks will offer enough protection to stop
radioactivity from escaping in the long term is impossible to predict.
An example of where industry plans
have been exposed as flawed is the proposed dump site at Yucca Mountain in
Nevada, US. After nearly 20 years of research and billions of dollars of
investment, not one gram of spent fuel has so far been shipped to the site from
nuclear reactors. Across the US., Major uncertainties in the geological
suitability for waste disposal at the site remain, with on-going investigations
into manipulation of scientific data and the threat of legal action by the State
government.
In addition to high-level waste
problems, there are numerous examples of existing disposal sites containing low
level waste which are already leaking radiation into the environment. Drigg in
the UK and CSM in Le Hague, France being just two.
Currently no options have been able
to demonstrate that waste will remain isolated from the environment over the
tens to hundreds of thousands of years. There is no reliable method to warn
future generations about the existence of nuclear waste dumps.
We have created a serious problem by poluting the earth with the most toxic, poisonous, radioactive substance on the face of the earth. Man has created it, and it has not yet found a way to get rid of it without harming the enviorenment or the public safety. We should have been working on this problem decades ago, but we have put into the back seat until it is now almost too late.
Does this mean that we should abandon the nuclear reactor program? Not at all. But we first should recognize that we have a hazardous nuclear-waste problem and we should make every effort to try and solve it before we get too much further. Otherwise, we may get ourselves into a condition that is completely out of control, and we may not be able to reverse the consequences.
In closing, I would like to read the following article written by Gail Gallessich:
By GAIL GALLESSICH
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Recent studies show that we have a "weapons-grade Catch-22" when it comes to managing the nation's existing problems of nuclear contamination, according to nuclear waste expert William R. Freudenburg.
"The best evidence we have tells us that institutional management systems cannot be counted on to protect public safety and the environment at these sites," he said. "At the same time, however, the remaining contamination problems are so severe that we have no alternative but to depend on such systems until we can think of something more sensible to do."
The problem has received recent national attention due to a court case attempting to prevent the creation of a nuclear dump at Yucca Mountain in Nevada, 90 miles from Las Vegas. According to government plans, waste will be shipped to Nevada from more than 100 sites across the U.S. The government says that the waste will be hazardous for 10,000 years, although others maintain that it will remain radioactive for 300,000 years.
Freudenburg, professor of environmental studies and sociology, recently chaired a session on the challenges of long-term nuclear waste management at the annual meeting of the American Association for the Advancement of Science in Seattle.
He has studied the problems of nuclear waste extensively and has contributed to various Department of Energy and National Academy of Sciences committees on this topic for more than 20 years.
"Although we are not spending money on this now, as a nation we really should be," he said. "Either we deal with it seriously now, or our children will have to deal with it expensively in the future."
Freudenburg explained that there are approximately 140 sites where nuclear weapons production took place. "Over 100 of these sites are so contaminated that we don't know how to clean them up," he said. "We have no choice but to rely on fallible human institutions to manage them."
He emphasized that society must count on institutions, but warned that we really cannot do so. Freudenburg said that the nation needs to expect that things will go wrong, and to figure out ways to simplify the work 30 years from now. He suggested the possibility of putting improved sensors in burial vaults, so that in the future it will be easier to find out where something is leaking and why.
"We need to try to find the consequences of nuclear waste leakage before it gets into the groundwater, at which point it has spread and might even be affecting thousands of people," he said.
For example, he said that if you have a nuclear waste burial site that cannot maintain its integrity if tree roots grow through a "cap" on the surface, and if the site is in a region where ground tends to be covered by trees, then failure is virtually guaranteed.
"We need to plan for failure, to expect that things will go wrong, and to ask what kinds of things are likely to go wrong," he said.
That even includes nuclear sites where history was made. The first controlled nuclear reaction by Enrico Fermi and his team of scientists happened in a squash court under the seats of Stagg Field at the University of Chicago. Yet the original squash court has long since been torn down, and the area that is called Stagg Field today is several blocks away from the historic location, Freudenburg pointed out.
"Even today, although the breakthrough itself is well recorded in the annals of history and science, there is not so much as a sign, or even a bronze plaque, that marks the site itself," he said.
"The difficulties are daunting, even at the sites that ought to fill us with pride; for sites that inspire less favorable reactions, the track record is worse."