Energy Facts

ENERGY CALCS REV 7.xls The spreadsheet for this article. You need to have Microsoft Excel in your computer to run it. Sometimes opens behind web page. 11/19/06 REV. X

The U.S. Gross Domestic Product for 2006 will be $13.6 trillion, $45,300 per person. We will spend an average of $3,800 on energy for each adult and child in the U.S. 86% of our energy comes from fossil fuel. We will discharge 44,000 pounds of CO2 per person in 2006. The Department of Energy’s Research & Development budget for non fossil energy sources (nuclear, hydrogen, solar, wind, hydroelectric, geothermal and biomass) is less than $0.7 billion, about $2.00 per American, in 2006.

We should be investing an amount equal to at least 5% of our energy budget on R&D for non fossil energy sources. That would be $191 per person, $57 billion per year. With this level of investment we can push every technology very hard. The best technologies, whatever they are, will emerge as leaders in the shortest possible time. The new technologies will tend to suppress rising fossil fuel cost. I believe the savings could surpass the annual R&D cost within 15 – 20 years, and save over $1,000 per year per person within 30 years, not to mention a large improvement in environment and quality of life with this approach.

In 2005 the United States consumed 4.04 billion megawatt hours (mWh.) of electric energy. Dividing that by the 296 million people in the United States then gives an average annual consumption of 13.6 mWh per American, about 1,550 watts, 24 hours a day. At $81 per mWh, a year’s supply of electricity cost $1,100. Over an 80 year lifespan, a lifetime supply of electricity would cost $88,300.

If all of our electricity came from a single fuel source how much would be required for an average person in the U.S., what would it cost and how much CO2 would be released as a byproduct of that production?

	Coal $31/TON	Oil $49/BARREL	Natural Gas $7.45/KCF	Uranium $17/POUND
Annual Amount	14,200 lb	17.2 barrels	115,000 cubic ft	0.723 lb
Annual Cost	$218	$841	$854	$11
Annual CO2 Production	30,600 lb	24,000 lb	13,400 lb	0 lb
Lifetime amount	1,140,000 lb	1,370 barrels	9,170,000 cubic ft	57.8 lb
Lifetime Cost	$17,500	$67,300	$68,300	$867
Lifetime CO2	2,440,000 lb	1,920,000 lb	1,070,000 lb	0 lb

Converting 5.4 ounces (0.34 lb) of Uranium to fission products will release enough heat to generate a lifetime supply of electricity for an average American with no CO2 emissions. Our primitive first generation nuclear plants split less than 1% of the Uranium mined to fuel them. In order to produce 5.4 ounces of fission products we mine 58 lb of Uranium.

Most electricity is made from the heat of burning fossil fuel or nuclear fission, by power plants with efficiencies ranging from 30 to 45%. Some electric power is lost in transmission. It takes 4,500 watts of source energy to generate our 1,550 watts of electrical power.

Electricity production accounts for about 40 % of all the energy that supports our lives. Most of the rest comes from the direct combustion of fossil fuel. Our total energy consumption is distributed as shown on the next page.

The total amount of source energy that supports our life is about 11,300 watts per person. Imagine the heat from 11 one thousand watt hair dryers running at maximum power 24 hours a day, for each of us, from cradle to grave.

If we derived all of our energy from a single fuel source how much would the average American need?

	Coal $31/TON	Oil $49/BARREL	Natural Gas $7.45/KCF	Uranium $17/POUND
Annual Amount	33,800 lb	39.6 barrels	337,000 cubic ft	1.7 lb
Annual Cost	$519	$1,940	$2,510	$29
Annual CO2 Production	72,600 lb	55,200 lb	39,400 lb	0 lb
Lifetime amount	2,700,000 lb	3,170 barrels	26,900,000 cubic ft	137 lb
Lifetime Cost	$41,500	$155,200	$201,000	$2,330
Lifetime CO2	5,810,000 lb	4,420,000 lb	3,150,000 lb	0 lb

Converting 13 oz (0.8 lb) of uranium to fission products will release enough heat to generate a total lifetime supply of energy for one average American, with no CO2 emissions. To produce 13 oz of fission products using primitive first generation nuclear power plants we mine 137 lb of uranium.

Hydrogen is often touted as the solution to our energy problems. It has important advantages;

· Low energy to volume ratio, fuel tanks are much larger and more expensive than fossil fuel tanks of equal energy content

· Multiple energy loosing transformations required for hydrogen systems offset the efficiency of fuel cells making overall efficiency little better than conventional systems

The biggest disadvantage of all is the fact that there are no hydrogen wells or hydrogen mines. Hydrogen must be extracted from water molecules or hydrocarbon fuel. The energy required to break water molecules apart, separate, store and transport the hydrogen must come from some other source. The source energy required is greater than the energy released when we reconstruct the water molecules in engines or fuel cells. Hydrogen is in essence a different kind of battery, not a source of energy.

For more details on hydrogen see the May 04 issue of Scientific American and the August 04 issue of Science.

· Stop burning fossil resources and preserve them for other applications by future generations

Advanced reactors can convert over 90% of mined uranium into fission products, increasing the utilization of uranium by a factor of 150, compared with our primitive first generation nuclear power plants. Using advanced reactors we can enjoy all of the benefits listed above and, at the same time, reduce uranium mining to 15 oz per lifetime, 3.3% of current uranium mining levels. A total energy lifetime supply of uranium costs $15, only 19 cents per year. For details on an advanced design see the 12/05 issue of Scientific American.

The oceans contain 4.5 billion tons of uranium, sufficient for over 30,000 years. In reality the oceans are continuously resupplied with uranium by the erosion of land, so the uranium supply is effectively unlimited.

It was a beautiful day for our snowshoe trip to the top of a 10,000 foot mountain, with fresh snow, deep blue cloudless sky, no wind, and temperature around 20 F, but it felt much warmer. I got some ribbing about being a nuclear engineer, mostly friendly, from the many environmentalists in the group. We reached the summit around noon and stopped for lunch. As we started to eat the normal chatter subsided until the only sound was of a young woman quietly sobbing. The leader went to her and asked what the problem was. “My feet are freezing.” She had worn canvas tennis shoes for her first snowshoeing experience, her shoes and socks became soaked with melted snow and now they were icing up “You’ll have to tough it out” he said, “I know” she said. We resumed eating in uncomfortable silence.

I walked over to her and said, “I might be able to warm up your feet”. I moved her to the center of the group where the sunlight was unobstructed. “Take off your shoes” I said. “No” she said, “why?” I asked, “Because I’ll have to put them back on” she said.

From childhood experience I knew that with the help of a campfire frozen tennis shoes can be transformed into giant flaming marshmallows with no sensation of warmth inside. NASA might have saved a lot of money on heat shield material by using old tennis shoes.

“I can’t get your feet warm wearing those shoes” I said. “I’m not taking them off” she said, “OK, let’s try it your way.”

I pulled out my high tech survival gear, a 55 gallon plastic garbage bag (black) and a disposable painters drop cloth (1/4 mil clear plastic). I inflated the bag, wadded it into a tight ball to wrinkle it, then inflated it again and had her put her feet inside. I unfolded the drop cloth, wadded up the plastic to wrinkle it, and then wrapped it loosely around the bag trapping a few layers of insulating air. “Give it some time” I said, trying to sound confident.

Several minutes went by and she stopped crying, a few more minutes and she said it wasn’t as cold, a few more minutes and she said it was warm, then hot, than very hot. “OK take your feet out”. She lay back flat on the ground, pulled her feet out of the bag and pointed them straight up. White clouds of water vapor billowed off her shoes and jeans. There was an audible gasp, not just mine, I touched the shoes and they were very hot. Others came up and touched them in amazement. A young man came forward eyes down, he sat next to the girl without a word and thrust his icy tennis shoes into the bag.

There was a Q&A session to explain the working principal of a solar oven. When their questions were answered I asked a question. “With all the solar buffs in the group why did it take a nuclear engineer to get her feet warm?” Silence. “In a rational world there is a place for solar energy, and a place for nuclear energy.” I don’t know if I made any converts but at least the ribbing stopped.

On the Sears web site you can buy a 3,600 watt gasoline powered generator for 590 dollars, 16 cents per watt of generating capacity. The problems are that fuel is expensive and the generator will probably be worn out in less than a year of continuous use. In 1980 solid state solar (photovoltaic) modules cost about $20 per watt. By 1996 they were down to $7 and in 2004 the price was $2.93 per watt.

Comparing cost per watt can be misleading. In 2005 nuclear power plants ran at a capacity factor of 90%. An average 1,000 megawatt nuclear power plant produced energy equivalent to a continuous 900 megawatts for the year. Solar cell ratings are for new cells with maximum solar flux perpendicular to the cell, at a relatively cool temperature, an ideal combination of conditions that rarely exists in real world applications. U.S. photovoltaic installations are concentrated in areas with ideal solar conditions and produce an average output equal to 15 % of rated power. If photovoltaic systems were distributed around the country in proportion to population they would deliver considerably reduced performance due to less optimum sun conditions where many people live.

What would it cost to replace the nuclear power plant with a photovoltaic plant? To achieve an average 900 MW with 15% average solar cell output and 0.95 inverter efficiency we would need an array with 6,170 MW peak output (900 MW / 0.15 / 0.95). At $2.93 per watt the array will cost $18.1 billion. In cold climates peak demand occurs in winter when days are short, sun angles are low and long periods of bad weather are common, a much bigger array would be required. We will need batteries to store excess power for night and periods of bad weather. Let’s assume the customers are willing to tolerate three blackouts a year, and an analysis of meteorological records shows that a two day supply of electricity will meet this criterion. We will need to store 63 million kilowatt hours of energy. At $136 per KWh the battery costs $8.6 Billion. We need a 5,000 MW battery charger, at 20 cents per watt that is $1 Billion. We will need a 1,000 MW inverter, at 80 cents per watt that is $800 Million. Add to this the cost of land (24,500 acres), construction, maintenance facilities, instrumentation and control systems, wiring, switchgear, administrative and engineering facilities, insurance, and the interest on the loan to build the plant, the total cost will be around $29 Billion.

Since we use 1,550 watts of electric power per person, this photovoltaic plant can supply all the electric power for 579,000 people. Each person’s share of the cost would be $49,600. The interest payments on a 30 year loan at a 7% rate, is $4,000 per year per person. The battery has to be replaced every 6 to 10 years. It weighs 3.3 Billion pounds, mostly toxic lead and sulfuric acid. Each persons share weighs 5,790 pounds. Assuming a 25% discount for the recycled lead and the maximum 10 year life, the recurring cost will be $6.5 Billion, $11,200 per person, adding $808 per year to the interest payment. Add to that, about $500 per year for operating expenses, maintenance, depreciation, profit, taxes, insurance, etc. It adds up to $5,300 per person per year, $390 per mWh.

Obviously no one will build a solar power plant like the one described above. The recurring battery replacement cost alone far exceeds the cost of a nuclear power plant that will run nearly continuously at max rated power, rain or shine, wind or calm, and last 40 to 60 years, whereas the solar cells will probably have to be replaced in 25-30 years.

In contrast to the above design there is an appealing grass roots approach to solar energy production that attracts a loyal following. This popular vision for converting solar energy is a distributed system of small installations on each house, factory, shopping mall, school etc. Each system would have its own battery and associated equipment. In essence the power plant is broken down into small pieces and distributed across the community. The problem is, this does nothing to reduce the cost of the plant. Each building will need its own system design. Each heavy cable in the large solar plant will be replaced by dozens of smaller wires that must be installed and terminated. Each large inverter, battery and charger in the solar plant will be replaced by several smaller units that will require more money and time to buy, install and maintain. The cost to build and maintain a distributed plant sized to replace a nuclear plant will be much higher than the above estimate due to the many more hours required to design, manufacture, install and maintain 250,000 customized systems.

In 1935 the U.S. government passed the Rural Electrification Act (REA). It took money from people living in cities and used it to build uneconomically justifiable power lines to serve farmers in rural areas. A condition for accepting this subsidy was that farmers had to give up their alternate energy sources such as windmills. You might think that the REA would be dismantled once the country was wired, but it is still going strong. Diehard supporters will tell you that without REA, farm children today would have to play computer games by candlelight.

Actually farmers are among the most productive and talented people in the country, also on average, among the wealthiest. A successful farmer is a good businessman, accountant, biologist, mechanic, heavy equipment operator, gambler and meteorologist. Left to their own devices each farmer would have found the best solution for his or her circumstances. Farmers would have developed windmills in windy areas, natural gas generators in areas with gas, water turbines in areas with running water etc. The United States would now have mature industries in each of these fields, more importantly, Americans would have a more realistic attitude about their capabilities.

Fortunately, other countries have taken a different viewpoint, notably the Netherlands, a country of 16.3 million people, about twice the area of New Jersey, has had a strong positive outlook on wind power for generations. Drive around the Netherlands and you will see windmills all over the place.

After more than three hundred years of evolution, state of the art windmills use advanced materials and engineering, and perform fairly close to theoretical maximum efficiency. Windmills will continue to improve in small increments as materials and technology evolve, but there is no room left for major breakthroughs, in sharp contrast to our primitive first generation nuclear power plants that extract less than 1% of the energy in the uranium mined to fuel them.

In 2005, 93% of Dutch electric power was generated by burning fossil fuel. Their 1,709 windmills produced 1.7%. Their single, small, primitive, 33 year old, first generation nuclear power plant produced 3.2%, nearly twice that of all their windmills combined. Their nuclear plant has produced $27 billion worth of electricity, and they are negotiating to extend its life to 60 years, about twice the life of windmills and solar cells.

The Dutch consume an average of 824 watts of electric power per person. The 1.7% generated by wind amounts to 14.3 watts per person. If the U.S. expands wind power to the same level as the Netherlands our 14.3 watts will amount to 0.92% of our electric power. It could be used to displace 41.2 watts of primary coal energy, 0.37 % of the 11,300 watts of primary energy consumed by the average American.

The real poster country for wind power is Denmark, a small collection of peninsulas and islands about twice the size of Massachusetts with a population of 5.4 million. Denmark has had a strong commitment to wind power for decades. In 1979 the government initiated a 30% subsidy for the cost of building windmills. In 1999 they guaranteed wind power producers 85% of retail, $90 per mWh, for all the power they could make. They imposed a tax on fossil fuel to provide an additional $38 per mWh to wind producers. Compare that with the cost to make electricity in the U.S. in 1999; hydroelectric $7 per mWh, coal $20 per mWh, natural gas turbine $39 per mWh, nuclear $19 per mWh.

If Denmark had issued these same huge incentives to nuclear power, they would be overflowing with generating capacity.

Denmark is to wind power what the perfect storm was to boating accidents. It has the, ideal combination of optimum factors.

· A small country with short transmission distances, each person lives within 50 miles of a shoreline

In 2005 wind accounted for 18.5 % of the 751 watts per person Denmark used, 139 watts of wind power per person.

The United States lacks the ideal conditions of Denmark, but if we could somehow match their 139 watts per capita, it would be enough to displace 402 watts of primary coal energy, only 3.6% of the 11,300 watts that supports our lifestyle.

Denmark’s 139 watts of wind power per person is several times higher than any other country, but it pales in comparison to the 301 watts per person we currently get from our primitive first generation nuclear power plants, displacing 869 watts of primary coal energy per person. If Denmark matched our 300 watts per person of nuclear power they could save 52% of the fossil fuel they burn to generate electricity.

· Best wind conditions are in the spring and fall when utility loads are lowest

· The best wind locations are in the plains states where population density is lowest. Most Americans live within a few hundred miles of a coast

· If wind farms ever provide a substantial fraction of our power they will require expensive, energy consuming, power conditioning equipment and batteries, not included in today’s cost estimates.

Conventional power plants are rated in megawatts. Wind and solar energy sources should be rated in terms of their average annual output, in megawatts. They are usually rated at peak output, four to seven times the average, or they are rated in terms of the number of homes they might supply, why is that?

In 2005 there were 296 million Americans living in 124 million homes, an average of 2.38 people per home. The average home uses 1,290 watts, 540 watts per person, 34% of the 1550 watts each person consumes. By quoting the equivalent number of homes an alternative energy facility might supply, they give the impression that the number of lives supported is three times the actual number.

You buy one third of the electricity that supports your life directly from the utility company, who pays for the rest? You do, every time you spend money. When you buy a loaf of bread you help pay the electric bills of the grocery, the baker, the farmer who grew the wheat and everybody else who contributed to creating that bread.

If you install enough solar and wind power equipment on your house to go off the grid, you replace one third of your electricity, 13% of all the energy that supports your life. You still have to pay the same as everybody else for the remaining 87%, which comes largely from fossil fuel. The cost of energy has a major impact on our cost of living and the quality of our lives.

1 On average, this wind (or solar) farm produces as much electricity as is consumed by 1,000 homes.

2 This wind farm can supply electricity for 1000 homes if it is connected to a large grid with enough conventional power plant capacity to meet peak demand and provide free battery and power conditioning service to the wind farm.

3 699 of these wind farms connected to a huge grid with enough conventional power plant capacity to meet peak demand and provide free battery and power conditioning service, could replace one nuclear power plant.

Which statement is most impressive, they all describe the same wind farm. The point is that conventional power plants can run at 100% of rated power for months to years at a time, whereas wind and solar equipment typically averages 15% to 25% of rated capacity. Comparing data plate ratings, “installed capacity”, is misleading.

Utilities using wind or solar power must have enough excess conventional capacity on line to maintain voltage during a lull in the wind or when wind exceeds the design limit of the wind farm causing it to shut down, or when a cloud drifts over the solar plant. That excess capacity is called “spinning reserve”, and the fuel consumed to maintain spinning reserve is not being used in the most efficient way. The excess fuel burned to maintain spinning reserve and provide power conditioning for wind and solar plants should be charged to those plants, along with the resulting CO2. Wind and solar power plants are not totally renewable, or emission free.

Wind and solar power supporters claim these plants are close to break even cost at $60 to $100 per mWh, but building windmill and solar plants does not allow utility companies to dismantle any conventional generating capacity. The only savings is the fuel not consumed when the wind blows or the sun shines. Fuel costs in 2004 were $18 per mWh for coal, $45 per mWh for natural gas turbines, $4.60 per mWh for nuclear plants, zero for hydro plants. Your utilities ratio of these sources determines the real break even cost for which solar and wind power would have to sell to avoid increasing your electric bill or taxes. The average fuel cost for the United States in 2004 was $20.10 cents per mWh, the real break even price for wind and solar.

The three countries with the highest percentage of wind generated electricity are, Denmark 18.5 %, Germany 4.3%, and Netherlands 1.7%.

The three countries with the highest electricity prices in the world in 2005 were, Denmark $297 per mWh, Germany $229 per mWh, and Netherlands $236 per mWh. That same year U.S. residents paid $94 per mWh. France gets about 80% of its electricity from nuclear power; their cost was $141 per mWh.

I do not hold France up as an example for us to follow, they run their nuclear power industry like the US runs the post office. The fact that their big government program can produce so much energy at a somewhat affordable price hints at the enormous potential nuclear has in a healthy competitive arena.

Denmark has ideal conditions for windmills and is decades ahead of the U.S. in developing wind power. The lesson of Denmark is that we can lavish huge subsidies on wind and solar in their embryonic stage with modest impact on our economy, but as they grow the negative impact of the subsidies grows with them.

Imagine that for the last 20 years the U.S. government gave away windmills and solar cells free to anybody who wanted them. How different would things be today? Not much really, because the recurring cost of batteries to store electric power is far higher than the cost of generating it as needed by conventional means.

The biggest problem with wind and solar is that they are presented as unlimited sources of clean safe free energy. That message enables the public to avoid the decision to move ahead with nuclear power, thereby deepening our dependence on fossil fuel.

To grow and process the corn for one gallon of ethanol takes 3,300 gallons of fresh water. Some of that water comes from underground aquifers that are being depleted. To fill a 20 gallon gas tank with E-85 (85% ethanol) requires 17 gallons of ethanol, the production of which consumed 56,700 gallons of water, 472,000 pounds of water.

Growing corn requires large quantities of nitrogen fertilizer which is made from natural gas, a non renewable resource. Nitrogen fertilizer imports have increased from 5% in 1991 to 50% in 2005.

Growing corn requires large quantities of potash fertilizer, a mineral deposit that is non renewable. Potash imports have increased to 90% of our consumption.

Growing corn requires large amounts of phosphate and lime, non renewable mineral deposits.

Growing corn requires pesticides and herbicides made from non renewable petroleum.

Growing and processing corn into ethanol consumes large amounts of fossil energy in the form of diesel fuel, gasoline, liquefied petroleum gas, natural gas and electricity made in large part from fossil fuel.

New ethanol plants are being designed to run on coal to avoid the high cost of natural gas.

The amount of fossil energy consumed per gallon of ethanol produced varies depending on assumptions and regional conditions. On average fossil energy consumed is about equal to the energy content of the ethanol.

The United States has lost about one third of its agricultural top soil in the last 200 years. The rate of top soil erosion is at least 6 times the rate that natural processes can replace it.

Streams and rivers are fouled by farm runoff containing fertilizer, insecticide, herbicide and top soil. Cost estimates for bio fuel do not include factors for pollution and erosion.

Humans have been consuming about 150 watts of bio fuel per person for over 200,000 years. Ironically the production of food in the United States consumes about seven times more fossil energy than the solar energy contained in the food.

Ethanol production is a non renewable, non sustainable industrial process. The numbers for bio diesel, switch grass, sugar cane, woodchips etc. are somewhat different, but the general conclusions remain the same.

If all of our agricultural assets were converted to energy production, leaving us with no food, it would replace only a modest fraction of the 11,300 watts we consume, even assuming a large improvement in agricultural energy efficiency.

The world’s food production system will be worn out in a very short span of geologic time. Trying to extract more energy from agricultural will accelerate that process with very little short term gain and great long term loss to future generations. This strategy is illogical and unethical.

Nuclear power had a honeymoon with the American people in its early days. The most enduring artifact of that honeymoon is the infamous phrase “Nuclear power will be too cheap to meter.” Ironically the cost of metering has dropped more than the cost of nuclear power. Wind, solar and ethanol are in their honeymoon phase now, and will remain so as long as they produce a small fraction of our energy, which is to say, the foreseeable future.

Earth has a diameter of 7,930 miles. The concentration of solar power at our distance from the sun is 1,147 watts per square yard. Calculating the area of earth’s disk and multiplying by the solar flux gives the power intercepted by the earth, 175,500,000,000,000,000 watts. Dividing by earth’s population, 6.5 billion, reveals that earth receives 27 million watts of solar power for each human on the planet. That’s not just at high noon on a clear day, that’s 24 hours a day every day. Some of that energy is reflected back into space by clouds and the earth’s surface while the rest is absorbed and later reradiated into space along with a relatively small amount of heat emerging from earth’s interior.

Over the suns 11 year cycle its output varies about 0.1%, 27,000 watts per human. Over the long term it has probably varied much more. The 11,300 watts that support our lives equals 0.04% of our share of solar incidence. With such enormous energy flows going all the time, how can our puny 11,300 watts change the earth’s temperature significantly? It cannot. The concern is that some of the gasses we are releasing into the atmosphere, including carbon dioxide, are restricting the reradiation of energy into space. A net 1% increase in the retention of solar flux would be an additional 270,000 watts of heat per person.

The point is that every human on the planet can enjoy a lifestyle more energy intensive than our own as long as we do it in a way that does not interfere with the natural energy balance of the earth. Fission is the only process available that can supply sufficient power to eliminate most combustion of fossil resources, and meet the world’s energy needs at an affordable price.

If we continue on our present course what will the consequences be? The worst case theory is that the Midwest will become a dustbowl again, lakes and rivers will dry up, the U.S. will not be able to feed itself, tropical diseases will move north, West Nile virus is just the tip of the iceberg. The ice caps will melt, coastal cities and shorelines will be inundated, property losses will be huge. The country will be battered by frequent high energy storms. Around the world millions of people now living in poverty on coastal lowlands will die because they lack the resources to start a new life elsewhere.

At the other end of the spectrum, global warming may result in a collection of mild climatic changes around the world, with winners and losers. The winners will enjoy a better lifestyle and the losers will move or make adjustments. High CO2 concentrations and warmer temperatures in higher latitudes may result in an overall increase in world food production.

In the past, earth has proven to be more robust than people thought. There may be climatic feedback control mechanisms that will mitigate the effects of the vast quantities of CO2 created by our current energy systems. But what about those pesky ice ages? If earths mitigating mechanisms are so great why didn’t they prevent the ice ages? I don’t know, more importantly, nobody knows for sure, there are no experts in climatology, only students of climatology.

Today we are running a vast uncontrolled worldwide experiment in greenhouse gas emissions that might have horrific consequences for hundreds of millions, even billions of people. Nuclear power is the only proven technology available with the potential to end this experiment.

Some people say they cannot support nuclear power until we have a permanent solution for nuclear waste. The most important thing to remember about nuclear waste is this.

The main reason we have not implemented a permanent solution for nuclear waste is the fact that we do not need one.

Suppose we built a large coal fired power plant. We will need two or three train loads of coal each week to keep it running. Coal is not pure carbon, it contains many other materials including rock, mercury, sulfur, uranium, thorium, cadmium, arsenic, radium, iron, and lead. Ironically, if the trace quantities of radioactive uranium and thorium were converted to fission products, they would release several times more heat than burning the coal. Some hazardous materials go up the stack into the atmosphere and the rest ends up in several truckloads of ash and dust each hour. If we don’t have a place to dispose of this waste our plant will soon be buried.

A nuclear plant can store 30 years of spent fuel in a medium sized swimming pool, so there is no pressing need for a permanent disposal site. The Department of Energy estimates that there will be about 292,000 spent fuel assemblies by year 2040, containing about 557 million feet of fuel rods. Fuel rods are less than one half inch in diameter consisting of small non flammable non explosive ceramic pellets inside sealed metal tubes. Each Americans share in 2040 will be 18 inches long, accumulated over 70+ years, about one fourth the volume of a Chap Stick cap each year.

From a technical point of view there are numerous solutions that would work, but most politicians want to keep their job, and the key to that is to be well known while offending the smallest number of people. Any decision they make on nuclear waste will offend a substantial number of people, so the option to do nothing is preferred. Ironically they may have taken the best course for now.

The earths crust and oceans contain atoms of uranium, a slightly radioactive metal 1.64 times the density of lead. Natural uranium consists primarily of two kinds of atoms, uranium 235 and uranium 238. Both have 92 protons in their nucleus, a small heavy collection of particles at the center of the atom, and 92 electrons forming a large cloud of negative charge surrounding the nucleus. Chemical reactions involve the trading or sharing of electrons, and since both kinds of uranium have the same electron structure, the two kinds of uranium cannot be separated by conventional chemical means.

When a uranium 235 nucleus absorbs a neutron it will most likely split into two large fragments releasing and an enormous amount of energy along with two or three neutrons and some radiation. The process is called fission, the large pieces are called fission products, and they are usually radioactive. If a sufficient concentration of uranium 235 atoms is present some neutrons released by fission will be absorbed by other uranium 235 nuclei, they, in turn, will likely fission, resulting in a self sustaining chain reaction.

Uranium 238 atoms will not support a chain reaction. When they absorb a neutron they will most likely go through a transition to become Plutonium 239, which can support a chain reaction.

Suppose we extract 6,000 lb. of natural uranium from the earth, enough to make a solid metal sphere 25.5 in. in diameter. It consists of 43 pounds of uranium 235, and 5,957 lb. of uranium 238. The concentration of uranium 235 atoms is too low to sustain a chain reaction because most neutrons are likely to be absorbed by uranium 238 atoms without causing fission. If we extract 4,766 lb. of uranium 238, the concentration of uranium 235 in the remaining 1,234 lb. will be 3.5%, suitable for use as reactor fuel. If we extract 5,954 lb. of uranium 238, we will have left 45 lb. of 95% uranium 235, sufficient to make a bomb.

The extracted material is called depleted uranium. Depleted uranium has commercial uses that take advantage of its high density including aircraft control counterweights, inertial weights in rotorcraft, armor piercing bullets, and radiation shielding. It can also be used to fuel advanced reactors.

The remaining product is called enriched uranium because its uranium 235 concentration is higher than that of natural uranium.

I once thought that radioactive atoms were like little radio transmitters spewing out a constant stream of radiation. I was completely wrong. A better analogy is to think of radioactive atoms as tiny sub nano firecrackers. Radioactive atoms emit no radiation at all until they reach end of life, then they explode in a spray of electromagnetic energy and/or particles. The process is called radioactive decay.

Each kind of radioactive atom has a characteristic rate of decay often described by the time required for one half of the atoms to decay (half life). After two half lives one fourth of the original atoms remain. After 10 half lives less then one in a thousand of the original atoms remain, after 20 half lives less then one in a million of the original radioactive atoms remain.

Nearly all of the uranium atoms on earth now were here when earth formed 4,700 million years ago, and none of them have produced any radiation. Only those uranium atoms that have decayed have produced radiation. When a uranium 238 atom decays it ejects an alpha particle (a helium nucleus consisting of two neutrons and two protons) and some gamma rays (electromagnetic energy similar to light but with much higher energy) with a release of 4.3 million electron volts (mev) of energy.

An electron volt (eV) is a small unit of energy useful for describing chemical and nuclear reactions. Chemical reactions, like combustion, involve a few eV per atom. The electrons illuminating a TV picture tube each have about 15,000 eV. Medical X rays have energies in the thousands of electron volts. Nuclear radiations have energies from thousands to millions of eV. Fission releases over 200 mev. Radiation from space can range over a billion eV.

The nucleus remaining after the uranium 238 decay is a thorium 234 nucleus. The thorium 234 nucleus is radioactive with a half life of 24 days. When it reaches end of life it will decay by ejecting a beta particle (an electron) thereby increasing the charge of the nucleus by one, creating a Protactinium 234 atom which is also radioactive.

The complete natural decay of one uranium 238 atom to stable lead 206 involves 14 decay events that release 8 alpha particles, 6 beta particles, and numerous gamma rays, with a total energy release of about 60 mev. Two of the more infamous decay products in this scheme are radium, which caused the horrific death of many luminous dial painters in the early days of nuclear technology, and radon gas, possibly responsible for tens of thousands of lung cancer deaths each year in this country alone.

The natural decay of a uranium 235 atom requires 11 steps including the emission of 7 alphas, 4 betas, numerous gammas and 56 mev of energy.

Like uranium 235, plutonium 239 is a heavy radioactive metal that can support a neutron chain reaction. It decays by alpha emission about 29,000 times faster than uranium 235, resulting in a half life of 24,110 years. It takes about a hundred thousand years for plutonium 239 to decay to the level of uranium ore.

Alpha particles are the civil war cannonballs of the nuclear world, not much range but they can do considerable damage up close. External alpha emitters are not a serious hazard because the dead cells on the surface of our skin can stop them. The main concern is that plutonium particles might become lodged in lung tissue, bombarding unshielded cells, possibly starting a cancer.

While new reactor fuel contains no plutonium, plutonium production from uranium 238 begins when the reactor starts up, and it is available for fission. Plutonium fission currently accounts for about 40% of all the power from our first generation reactors, 8% of all our electricity. Converting 13 ounces of plutonium to fission products will provide a lifetime supply of energy for one American.

We can extract the enormous amount of untapped energy in uranium 238 by converting it to plutonium 239 in advanced reactors and then into fission products.

Consider a 100 lb sample of reactor grade Uranium containing 96.7 lb of uranium 238 and 3.3 pounds of uranium 235.

It goes into a reactor where it is subjected to intense neutron bombardment. After three years it is removed. The composition of the spent fuel is shown below

The spent fuel has produced the equivalent of a lifetime supply of electricity for ten people, yet less than 4% of its potential energy has been extracted. Why remove fuel with so much potential energy remaining? Our primitive first generation reactors consume uranium 235 faster than they make plutonium. At some point the combined concentration of uranium 235 and plutonium 239 is not sufficient to maintain full power in the reactor, more uranium 235 must be added. To make room for new fuel the oldest third of the fuel is removed every 12 or 18 months.

There are at least 770 different kinds of atoms that may be produced when a uranium atom splits, most are radioactive. They generally decay to stable atoms through a chain of one to four decays.

Over 57 % of possible fission products have half lives shorter than one minute. They are subject to the possibility of decay from the moment they are created, they do not wait for reactor shutdown to begin decaying. Ten minutes after the reactor reaches full power these fission products are essentially in equilibrium, decaying as fast as they are being created. When the reactor is shutdown, over 99.9% of these fission products have decayed within 10 minutes. 82 % of possible fission products have half lives of less than one day. 6.6% have half lives between 1 day and 1 year, only 3.2% have half lives greater than 1 year, and 8% are not radioactive.

During the three years fuel spends in the reactor over 70% of the fission products decay to stable atoms, and most of the heat from those decays is used to make electricity.

Fresh fuel is made of naturally occurring materials and is slightly radioactive due to its uranium content. After three years in the intensely radioactive environment of a reactor, it is ironic to note that the discharge fuel contains fewer radioactive atoms than it did when new. That is because the number of uranium atoms consumed exceeds the number of fission product atoms that are still radioactive. Fresh spent fuel is intensely radioactive because the remaining radioactive fission products are decaying at a rate several hundred thousand times faster than the uranium atoms were. The good news is that the number of radioactive fission product atoms is dwindling rapidly on a geologic timescale. The fission products will be less radioactive than uranium ore within one half of one one-thousandth of one million years, (500 years).

Suppose we derived all our electricity from fission. An average American would be responsible for converting 5.3 ounces of uranium to nearly 5.3 ounces of fission products over an 80 year lifetime. During that life most fission products will decay to stable atoms, leaving 0.67 ounces of radioactive fission product atoms at end of life, not enough to fill a shot glass. If we derived all our energy from fission, an 80 year lifetime would convert 13 ounces of uranium into fission products and leave 1.63 ounces of radioactive atoms at end of life.

The natural decay of 13 ounces of natural uranium to stable lead produces about seven times the radiation produced by the decay of 13 ounces of fission products. In the end, the natural process leaves you with 13 ounces of lead that remain toxic forever, whereas most fission products decay to non toxic atoms.

The point is that nuclear reactors do not make nuclear waste, they convert long lived naturally occurring nuclear waste into short lived nuclear waste, while releasing enormous quantities of useful energy.

Uranium 238 has a half life of 4,468 million years, so 4,468 million years ago there were twice as many uranium 238 atoms as there are now. When the earth formed 4,700 million years ago there were 2.07 times as many uranium 238 atoms as there are now, so the 5,956 pounds of uranium 238 in our 6,000 pound sample of natural uranium, are the survivors from an original 12,350 pounds of uranium 238.

Uranium 235 has a half life of 704 million years, so when the earth formed 6.6 half lives ago there were 102 times as many uranium 235 atoms as there are now. The 43 pounds of uranium 235 in our 6,000 pound sample are the survivors from an original 4,424 pounds of uranium 235.

When earth formed, natural uranium had a uranium 235 content of 26%, over seven times more concentrated than our power reactor fuel. As recently as 1,700 million years ago, a uranium deposit at Oklo, in Gabon Africa, supported at least 17 natural reactors that operated off and on when the ore was flooded with ground water, splitting a large quantity of uranium atoms. Studies show that the plutonium and most fission products remained very close to their point of origin despite the presence of moving water and the lack of engineered barriers.

If the last chain reaction at Oklo stopped exactly 1,700 million years ago, we can say with certainty that for the last 1,699.9 million years, that site has been less radioactive than it would have been if those reactors had not formed. That is because without those reactors, the uranium they destroyed would still be generating radioactive decay products and toxic lead. In the same way man’s nuclear power industry will leave the world less radioactive for most of its remaining life than it would have been without nuclear power.

The point is that the disposal of fission products is not a particularly new or difficult problem, though we can make it as difficult and expensive as we choose.

Ask a dozen experts to design a plan for the disposition of nuclear waste and you are likely to get a dozen different plans. Most likely, any of them will do the job if carefully implemented. Here is one possibility.

1 When fuel is removed from the reactor it goes into the spent fuel pool. Water is the ideal medium for fresh spent fuel because of water’s excellent shielding characteristics, high heat capacity, and transparency.

2 After several years the heat rate is low. The fuel is transferred into dry cask storage, a hermetically sealed container, vacuumed to remove all trace of moisture, and then partially filled with helium, a non corrosive gas with good heat transfer properties. The cask is shielded by thick layers of concrete and steel.

3 Maintain a low level R&D program to incorporate advances in materials and technology into the development of a fully automated fuel recycling system.

4 Develop commercial applications for radioactive and non radioactive fission products.

5 As time goes by the value of the material in spent fuel increases while the cost of reprocessing decreases. When those two curves cross reprocessing becomes economically attractive and should begin.

6 Uranium and plutonium are recycled into advanced reactors, useful fission products are sold.

Scientists at Woods Hole Oceanographic Institute were asked to look at ocean disposal for nuclear waste. Oceanographers spend most of their life on, in or near the sea. They love the ocean, so the idea of putting waste there was not appealing. Being good scientists they looked at the possibilities and found that the oceans contain large areas of deep dense mud ideally suited for retaining fission products. The containers will be designed to last far longer than the brief period of geologic time required for the fission products to decay to safe levels. If a container fails the mud will contain the fission products. If any fission products escape from the mud they will be quickly diluted to safe levels in the seawater which contains a huge mass of naturally occurring radioactive material, far greater than the amount produced by human activity.

Humans live on one fourth of the earth’s surface. It makes sense to dispose of nuclear waste under a very small portion of the other three fourths.

The nuclear power industry contributes $1.00 per mWh to a government held fund to dispose of nuclear waste. The industry has paid in $24.8 billion, of which $6.6 billion has been spent, very inefficiently, to study a dry land repository.

Have you ever cringed at the sound of fingernails being dragged across a blackboard? That’s the way nuclear engineers feel when they hear “Chernobyl and Three Mile Island” used in a sentence as if they were similar events.

One evening in the library at school I came across a magazine article on the then new RBMK 1000 reactor design to be built in the Soviet Union. There are many ways to split the uranium atom and it is interesting to see how teams from other countries have addressed the challenge. After a few minutes of reading, the hair on the back of my neck began to stand up. The Russians were taking two huge risks in the design of this reactor that would not be allowed in the U.S.. I asked a respected professor what he thought of the Russian technology. His response was “They are taking a big chance”. Years later when reports came of a serious reactor accident in Russia it was disappointing but not a surprise.

In U.S. reactors fast moving neutrons slow down in collisions with the nuclei of water molecules, increasing the probability they will be absorbed by a uranium 235 atom and produce another fission. When water heats up or boils to steam, its density is reduced and the neutrons are not slowed as effectively, producing a negative impact on the reaction rate.

In the RBMK reactor, the slowing down function is provided by carbon atoms in the form of graphite blocks. Water runs in pipes through the core to extract heat, but is not needed to sustain the chain reaction, in fact the water has a small negative impact because some neutrons are absorbed by hydrogen nuclei in the water molecules. If the water turns to steam, water molecules are forced out of