U.S. Department of Office of Nuclear Energy

Table of Contents

Lesson 1 - Energy Basics

Lesson 2 - Basics

Lesson 3 - and

Lesson 4 - Ionizing

Lesson 5 - Fission, Chain Reactions

Lesson 6 - to Electricity

Lesson 7 - Waste from Nuclear

Lesson 8 - Concerns

Lesson 9 - Energy and You


Radiant Energy

Mechanical Energy

Introduction This lesson will look at the states and forms of energy. Next we will look at where energy comes from. Finally, we’ll explore how the way we live is tied to our and what that means for the future.

TOPICS: States of energy What is energy? is the ability to do . But We use energy all the . Whenever Kinetic what does that really mean? work is done, energy is used. All activities Forms of energy Mechanical involve energy. Chemical You might think of work as cleaning your Nuclear Electrical room, cutting the grass, or studying for a We need energy to Radiant test. And all these require energy. • power our factories and businesses Energy from and our homes and schools sources To a scientist, “work” means something • run our appliances and Primary and secondary more exact. Work is causing a change. It • stay alive and keep our bodies moving sources Renewable vs non- can be a change in position, like standing • build and our cars, trucks, planes, renewable up or moving clothes from the floor to and ships Conversion Conservation the laundry basket. It can be a change in • run and videos Environmental effects , like heating for a cup • power our phones, computers, music, Greenhouse effect of tea. Or it can be a change in form, like and games Climate change the water in tea changing from liquid to • make our clothes Future sources steam. All of these things are work and • and do everything else that we do require energy.

Lesson 1 Energy Basics 1 Lesson 1 ENERGY BASICS

What are the states of energy? Potential We can divide energy into two basic states: potential energy and . Potential energy is stored energy that is waiting to be used. Kinetic energy is energy of . A roller coaster at Kinetic the top of the track has potential energy. When the roller coaster down the track, the potential energy is changed into kinetic energy. Heat, light, and motion all indicate that kinetic energy is doing work. Potential energy is often harder to detect. It must be changed into Potential energy is stored energy. Kinetic kinetic energy before we can use it. energy is energy of motion.

What are the forms of energy? There are many forms of potential and kinetic energy. These include mechanical, chemical, thermal, electrical, radiant, and nuclear energy, as well as the energy of gravity. • is the • is the flow of tiny energy that moves objects charged particles called by applying a . It can . Electrons move be kinetic – the motion of through a conductor, such a snapping mousetrap. Or as a copper wire. it can be potential – the • is energy tension in a set mousetrap. traveling as waves. It • Chemical energy is the includes visible light, radio energy released when the OHOH waves, x-rays, and gamma chemical bonds of a material O O OH rays. The Sun’s energy HO change. stores O comes to us in this form. OH chemical energy that is HO OH • Energy from gravity is the energy OH released when it . of position or place. The • Nuclear energy is the energy stored potential energy of water in the center (nucleus) of an held behind a dam is atom. It’s the energy that changed to kinetic energy holds the center together. when it is allowed to flow The energy can be released downhill. when the center splits apart • Thermal energy is heat or when centers fuse together. energy. We use it to cook meals, to manufacture products, and to generate electricity.

2 The Harnessed Atom: Nuclear Energy & Electricity is the name for materials from plants and animals that have chemical energy stored in them. The energy in biomass originally came from the Sun. A biomass fuel we all know is wood for fireplaces and wood stoves. Other examples are crops such as corn and switchgrass, manure, garbage, and methane OHOH O O OH HO from landfills. By burning biomass, O OH we release its stored chemical HO OH OH energy as thermal and radiant energy. We also can convert it to , such as ethanol and biodiesel. Biomass provided about 4.6 percent of the energy used in the United States in 2012. PlantsIn use the photosynthesis process of to photosynthesis, store energy from the Sun.plants In the convert process radiantof photosynthesis, energy from plants convertthe radiant sun intoenergy chemical from the Sunenergy into chemicalin the Radiant energy from the Sun’s energy in theform form of sugarsugar or orstarch. starch. rays make some parts of the Earth warmer than others. Air waterWhere + carbon dioxidedoes + energy come from? glucose + oxygensurrounding these warmer surfaces is O + 6 CO + radiant energy C H O + 6 Oheated, which causes it to rise. Cooler air 6 H2 Much of the2 Earth’s energy comes from6 12 6 2 then flows in to replace the heated air that the Sun in the form of radiant energy. has risen. We call this flow of airwind . Plants convert this energy to chemical energy by a process called photosynthesis. This chemical energy is stored in the form of sugars Warm air over rises and starches, which provide energy for the as well as people and animals that eat the plant. When we plants such as trees, stored chemical energy is converted and Land up faster than water released in the form of heat (thermal energy) and light (radiant energy),

which we call fire. Cool air over the water moves in

Air moves because of changes in air pressure. is air in motion caused by the Sun heating the Earth’s surface. Wind World Population can be used to produce electricity. Early humans <1M control fire


31,000 BCE 30,000 BCE 29,000 BCE 28,000 BCE 27,000 BCE

Lesson 1 Energy Basics 3

DOE Clearance Draft - Not for Distribution Lesson 1 ENERGY BASICS

Radiant energy from the Sun also causes What is ? water to evaporate into . The Primary energy is energy found in nature water vapor rises into the upper before we convert it to do work. Primary where it forms clouds and . energy sources are This is called the water cycle. The • (sunlight) tremendous energy in storms and • Water power (flowing water) is actually caused by the Sun’s radiant • Wind energy (moving air caused by energy. the Sun heating the atmosphere) • Biomass (plants) When it , the water flows down • Tidal energy (the effect of the gravity rivers. The energy in moving of the and Sun on the oceans) water can turn a watermill or • Nuclear energy (energy from inside to make . and ) About 300 million years ago, countless • (heat from inside plants and animals died and were slowly the Earth) buried beneath layers and layers of • energy (, , oil). dirt and sand. Heat and pressure We consider fossil fuels to be primary from these layers concentrated the energy sources even though they chemical energy stored in them, originally took their energy from the slowly changing them to the fossil fuels oil, Sun and stored it as chemical energy coal, and natural gas.

PetroleumPetroleum & and Natural Natural Gas Gas FormationFormation

Tiny sea plants and Over millions of years, Today, we drill down animals died and were the remains were buried through layers of sand, buried on the ocean deeper and deeper. The silt, and rock to reach floor. Over time, they enormous heat and the rock formations were covered by layers pressure turned them that contain oil and of sand and silt. into oil and gas. gas deposits.

Ocean Ocean

Sand & Silt Sand, Silt, & Rock Plant & Animal Remains Oil & Gas Deposits

300-400 million 50-100 million years ago years ago Today

Petroleum was formed millions of years ago from the remains of plants and animals under heat and pressure. WORLD POPULATION

26,000 BCE 25,000 BCE 24,000 BCE 23,000 BCE

4 The Harnessed Atom: Nuclear Energy & Electricity What are secondary energy use up these , they will be gone. sources? In the United States, most of the energy There are also secondary energy sources we now use comes from non-renewable that are produced by using primary energy. sources. We use them to make electricity, Electricity is a secondary source that can heat our homes, move our cars, and to be produced from any of the primary manufacture goods. sources listed. Ethanol is a secondary energy source made from biomass. How do we convert energy from one form to another? What are renewable and non- The law of says sources? that energy can change from one form We can further divide the primary and into another, but it cannot be created or secondary energy sources we use into destroyed. In fact, when we say that we use renewable and non-renewable sources. energy, we really mean that we convert and Renewable sources can be continuously harness it to do the work we need to do. replaced. Day after day the Sun shines, the wind blows, plants grow, and rivers Energy is converted in hundreds of ways. flow. We use renewable energy sources in For example, burning gasoline to power our wood stoves, to make electricity, and cars is an energy conversion process we to make alcohol and biodiesel fuel for rely on. The chemical energy in gasoline cars. Non-renewable sources cannot be is converted to thermal energy, which is replaced. The supplies of coal, oil, natural then converted to mechanical energy that gas, and uranium are limited. When we makes the car move.

Think about it...

Renewable energy sources are constantly being replaced. Having an energy supply we can use now and also count on into the future is important. But right now there are limitations to using renewable energy. First, there is the intermittent nature of the sources. The wind does not always blow, the Sun does not shine at night, and dry spells reduce the flow of rivers for hydropower. Second, the high cost of some of the used for harnessing renewable energy drives up the cost of energy from these sources. Third, there are costs for getting power from renewables to customers. There are also impacts on the environment. For example, hydropower does not produce carbon dioxide like burning fossil fuels, but building a dam does alter the area where it is built. This may affect plants and animals.

22,000 BCE 21,000 BCE 20,000 BCE

Lesson 1 Energy Basics 5

DOE Clearance Draft - Not for Distribution Lesson 1 ENERGY BASICS

this heat because when you work hard you get hot. Your body converts the chemical energy in your into mechanical energy, but some is lost as wasted heat.

What is efficiency? Each time we convert energy from one form to another, we lose some of it, often as heat. We must constantly put more energy into machines or they will run down. A Our bodies convert the or system that converts energy without chemical energy wasting much is very efficient. In fact, most in food we eat energy conversion processes are not very into thermal and mechanical efficient. As a result, energy is lost to the energy when we environment. Only about 25 percent of the exercise. energy we use in our bodies or automobiles is converted into mechanical energy. The rest is lost as heat. When a conversion process The mechanical energy has been wastes a lot of energy, it is called inefficient. converted to kinetic energy. When we

use the to stop a car, that kinetic The first law of Energy changes from one energy is converted by back to form to another, but it can’t be heat, or thermal energy. explains why... created or destroyed.

The second law of Every time energy is converted from one form to another, there Our bodies are also powered by converting thermodynamics is less energy available to do energy. We must convert the energy in explains why... useful work. food into other forms of energy, such as mechanical energy so we can move, or thermal energy to maintain body When we do not convert energy efficiently, temperature. When we exercise, we also it costs money and wastes valuable produce a lot of heat energy. You can feel resources. This is why people today are

Think about it...

An incandescent light bulb gets very hot. A fluorescent bulb gets warm. An LED light stays cool. Which do you think is most efficient in converting electricity into light?


19,000 BCE 18,000 BCE 17,000 BCE 16,000 BCE

6 The Harnessed Atom: Nuclear Energy & Electricity looking for ways to save energy by carefully know it’s a place to grow plants, even in using our energy resources and by trying to winter. Usually a greenhouse looks like a convert energy as efficiently as possible. glass building. The glass lets the radiant energy from the Sun in, but as the light How can we save energy? passes through the glass, its get Wasting less energy is called conservation. longer and cannot pass easily back out of the Although conservation is not an energy glass. The radiant energy is trapped as heat. source, we can use it to make non- renewable energy sources last longer into Some in the atmosphere trap heat the future. We can all practice conservation in much the same way as a layer of glass. by being careful about how much energy They are called greenhouse gases. The we use. Some things we can do are rise in temperature that results is called the • Carpooling greenhouse effect. • Driving less, , and biking • Using public transportation, like Sunlight enters the Earth’s subways and buses atmosphere. The land, water, and • Setting the thermostats in our homes, atmosphere absorb the radiant energy. Some schools, and work places to reduce of the energy reflects back through the waste atmosphere to , but some is trapped • Reducing, reusing, and recycling things in the atmosphere by greenhouse gases. instead of throwing them away Increasing the amount of greenhouse gases • Turning off and appliances when in the atmosphere traps more heat, causing they are not being used to rise. Global warming is • Insulating our homes a planet-wide rise in temperature. Rising • Using energy-saving light bulbs • Unplugging chargers for our phones and music players when we are not using them

Because conserving energy has become more important, manufacturers are making more efficient machines. Choosing cars that are more efficient helps. Also, families can purchase appliances that have good energy efficiency ratings.

What are some environmental impacts of our energy use? Recycling is one thing that families can do to help If you’ve ever been to a greenhouse, you save energy.

15,000 BCE 14,000 BCE 13,000 BCE

Lesson 1 Energy Basics 7

DOE Clearance Draft - Not for Distribution Lesson 1 ENERGY BASICS

temperatures may cause changes in Each way we produce energy affects our rainfall, the strength of storms, melting environment in some way. Think about polar , and rising sea levels. This is the effects of called climate change. • coal and uranium • Drilling for oil Greenhouse gases occur both naturally and • Fracturing underground rock for as the result of human activity. Some of the natural gas and geothermal wells major greenhouse gases are • Damming rivers for hydropower • Carbon dioxide (CO ) – released 2 • Cutting trees when we burn oil, coal, and natural • Placing in the sea for tidal gas. It also comes from biomass and power volcanoes. • Using large tracts of land for wind or • Methane (CH4) – comes from landfills, coal mines, oil and natural gas solar farms operations, and agriculture. • Disposing of wastes from burning coal or from plants • Nitrous oxide (N2O) – comes from the use of nitrogen fertilizers and burning fossil fuels. It is important for us to use our energy resources wisely and protect the environment.

The Greenhouse Effect in the atmosphere Some solar energy is absorb and re-emit heat in all directions. The reflected by the Earth effect of this is to warm the Earth’s surface and and the atmosphere. the atmosphere.

Solar radiation energy passes through the clear atmosphere. Most is absorbed by the Earth’s surface and warms it.

World Population 3M


12,000 BCE 11,000 BCE 10,000 BCE 9,000 BCE

8 The Harnessed Atom: Nuclear Energy & Electricity Our Total Energy Use, 2012 Solar 3% Geothermal 3% Wind 15% Biomass waste 11% 37% Biomass 44% 49% * Wood 45% Natural Gas Renewable 9% 27% Biomass 49%

Coal Nuclear Hydropower 30% 18% 9%

Note: Sum of biomass components does not equal 53% due to independent rounding. Source: U.S. Energy Information Administration, Monthly Energy Review, Table 10.1 (April 2013), preliminary 2012 data.

About 91 percent of the energy used in the United States in 2012 came from non- renewable sources. Renewable sources provided about 9 percent.

Which energy sources will We’ll have to think about we use? • The available supply of each More and more, people are becoming and where it is located. For example, aware of how crucial energy is to our way we buy almost half of our oil from of . There is also a growing awareness other countries. For our national that we will need to make some changes security, many people want us to be in the energy sources we rely on and about able to produce the energy we need how we use energy. Most people think from U.S. sources. we will need to use many different energy • The cost of the energy we need. sources. But our choices are complicated. • Which resources can provide enough

of the energy we need.

Farmers harness World Population oxen to plow fields 5.3M

8,000 BCE 7,000 BCE 6,000 BCE 5,000 BCE

Lesson 1 Energy Basics 9

DOE Clearance Draft - Not for Distribution Lesson 1 ENERGY BASICS

• The on the environment from obtaining the energy resource. • The impact on the environment from using the resource.

• Choosing energy sources that work best in different parts of the country.

Neutron Energy

During our lifetime, the ways we use and supply U-235 Fission Product our energy will change. We will need to use U-235 energy more wisely and protect the environment better.

1859 CE First oil production well drilled in Pennsylvania 1826 CE John Ericson builds hot-air engine powered by the sun 1803 CE Steam invented

1787 CE Steamboat invented 1300 CE Hopi Indians use coal 1785 CE First water-powered fabric loom invented for heating, cooking, and firing pottery. Anasazi Indians build 1698 CE First steam invented cliff dwellings with southern exposures for solar heating 1100 CE Windmills introduced in Europe 644 CE First vertical axis windmill used in

Hot springs used for bathing, World Population cooking, and heating by Romans, 85M Japanese, and others


4,000 BCE 3,000 BCE 2,000 BCE

10 The Harnessed Atom: Nuclear Energy & Electricity 2011 CE Energy Use Timeline World Population 7B 1957 CE World’s first large-scale , is 1/2 meter Shippingport, Pennsylvania (1.6 feet) above this page 1954 CE Solar voltaic cells invented Neutrons 1942 CE Fermi team’s first self-sustaining Energy


Fission Product 1904 CE First plant built in Italy U-235

1890 CE Solar engine used to run a printing press

1887 CE First automatically operating

1885 CE Gasoline-powered automobile invented

1880 CE Coal is used to generate electricity

1860 CE Gasoline-powered engine invented

1804 CE World Population 1B

World Population Romans use Water-powered grain 300M coal for heating mill used in Asia Minor

1,000 BCE 0 1,000 CE 2013 CE

Lesson 1 Energy Basics 11

DOE Clearance Draft - Not for Distribution Lesson 1 ENERGY BASICS


Energy is the ability to do work. We can convert energy from one form to another, but we cannot create or destroy There are two basic states of energy — energy. potential and kinetic. Potential energy is stored energy. Kinetic energy is energy in Saving energy is called conservation. motion. Although conservation is not an energy source, we can use it to extend the time There are many forms of potential and non-renewable sources will be available. kinetic energy, including mechanical, chemical, thermal, electrical, radiant, There are environmental impacts from nuclear, and the energy of gravity. the use of all energy sources. One impact is from greenhouse gases, which most The primary sources we use today scientists believe are contributing to are fossil fuel energy, nuclear energy, climate change. Mining, drilling, and geothermal energy, solar energy, and tidal building dams affect the land and water. energy. All these can be used to make There can be spills that affect the oceans electricity, a secondary source of energy. and .

Energy sources can be divided into Meeting our energy needs during your renewable and non-renewable sources. lifetime will be different than in the past. Non-renewable sources cannot be replaced. Renewable sources can be replaced.

12 The Harnessed Atom: Nuclear Energy & Electricity Lesson 2 ELECTRICITY BASICS Introduction It’s difficult to imagine life without convenient electricity. You just flip a switch or plug in an appliance, and it’s there. But how did it get there? Many steps go into providing the reliable electricity we take for granted. In this lesson, we will take a closer look at electricity. We will follow the path of electricity from the fuel source to the home, including the power plant and the electric power grid. We’ll explore the role of electric utilities in the generation, transmission, and distribution of electricity.

TOPICS: Basics of electricity Generating electricity What is electricity? it as static electricity when your hair is Similarities of power Of all the forms of energy, electricity is attracted to a comb or when there is a plants the one we rely on most in our day-to-day Distributing crackling as you take off your sweater. electricity . In fact, we are so accustomed to using Generation Transmission electrical energy that we tend to take it for How is electricity produced? Distribution granted – until service stops and everything Power grids To produce a steady flow of electricity, we use Smart grids comes to a halt. a generator. A generator is a coil of copper Utilities wire that spins inside a magnetic field. This Cost of electricity Regulation Electricity is our most versatile and produces a flow of electrons through the coil Deregulation adaptable form of energy. We use it of wire. Planning for the future at home, at school, and at work to run numerous machines and to heat and light buildings. Generator To scientists, electricity is the flow of tiny particles called electrons that have an electrical charge. Sometimes you see it in the sky as lightning or experience

Copper coil


Lesson 2 Electricity Basics 13 Lesson 2 ELECTRICITY BASICS

Generator Electric current

Boiler Copper coil Turbine Magnet Heat Steam

Fuel As steam flows over the blades of a turbine, kinetic energy turns the shaft.

Where is electricity produced? Who makes electricity? Electricity is generally produced at a power Companies that sell electricity to customers plant by converting one of the primary are called utilities. A utility provides sources of energy into electricity. something useful or essential to the public, like electric power, natural gas, or water. What energy sources do we use to make electricity? Because a utility provides an essential In the United States, the sources we use to service to its customers, it has special duties. make electricity are fossil fuels (coal, oil, or For instance, an electric utility must be natural gas), uranium, or falling water. We able to supply all the electrical needs of its also use , wind, biomass, and customers. A utility can’t promise to deliver geothermal sources. its product in two weeks the way some other

Most power plants are similar in several important ways. Fuels Used to Make Our Electricity They generate electricity by heating water to produce steam. The steam is then directed against the Nuclear Natural Gas blades of a turbine, 19% 30% Hydropower making it much 7% like the way air makes a windmill’s blades Renewables 12% spin. The turbine turns the generator Coal 37% and produces electricity. Petroleum 0.6% Biomass 1.5% Other Fuels 0.3% Other Gases 0.3% Wind 3%

Geothermal 0.4% Source: www.eia.gov, 2013 Solar less than 1%

14 The Harnessed Atom: Nuclear Energy & Electricity companies can. Electricity must be ready for With electricity, this “pressure” difference use all the time. This means there must be is called voltage. generating plants, fuel, and enough power lines to provide service at any instant. The There are three main steps in getting supply must be reliable. The cost must be electricity to customers: reasonable. • Generation – using a source of energy to produce electricity To make sure these conditions are met, State • Transmission – using high voltage and local governments regulate utilities. lines from the power plant to distribute When governments regulate, they make electricity to areas that may be far from sure the utility provides good services at the power plant prices that are fair to customers and the • Distribution – using lower voltage utility. In return, the utility is allowed to be lines, substations, and to the only one in its area. In some areas of the deliver electricity to local customers country, deregulation now allows customers to choose which company they buy their At one time, almost all of the electricity electricity from the same way they can select used in the United States came from a phone or internet company. However, companies that owned the power plants, State public utility commissions still transmission lines, and distribution regulate rates for customers, approve sites systems. Today, some companies are for generation facilities, and enforce State involved in generation, transmission, and environmental regulations. distribution, while other companies are involved in only one aspect of the industry. How do we get electricity to the place where we use it? What is the power grid? The electricity produced in the generator To get electricity to everyone who needs is sent out over wires to homes, schools, it, utilities send large amounts of electrical hospitals, farms, offices, and factories. power over long distances. This is done Getting it there is not a simple job. through a network of transmission lines called the power grid. At the power One way to think about how electricity plant, the voltage from the is distributed is to imagine water being pumped through pipes. The water flows from high pressure at the pump down Transmission Lines the pipes toward the lower pressure at your home. Generator Electric current

Transformer Boiler Copper coil Turbine Magnet Heat Steam Fuel

Lesson 2 Electricity Basics 15 Lesson 2 ELECTRICITY BASICS

The Main Interconnections of the one part of the grid to another. The U.S. Electric Power Grid three networks are the • Eastern Interconnection • Western Interconnection • Texas Interconnection

Western Interconnection Eastern These interconnections between Interconnection utilities allow them to meet changing energy demands. For example, a Texas utility that has a power shortage can Interconnection buy electricity from a utility that has a surplus. It also allows small companies or even individuals to sell The national power grid connects the 48 continental U.S. States. Alaska and Hawaii have their own grids. the electricity they generate to others. This is important because it helps us generator is increased to transmit it more use intermittent energy sources like efficiently. The high-voltage current is then hydropower, wind, and solar power. It also sent through the power grid to a substation means that if a company or even a family where it is transformed to lower voltages generates more electricity than it can use, for distribution to homes, schools, and the electricity can be sold so it isn’t wasted. industries. What is the “”? Over the years, transmission networks To make sure electricity is there when have evolved into three major power customers need it, utilities are investing grids in the 48 connected States. These in smart grid equipment. This wireless networks allow electricity to transfer from equipment lets the utility know what is The Power Grid The Power Grid

Generation of Transmission Distribution electricty

Electricity is distributed to homes and industry through a power grid.

16 The Harnessed Atom: Nuclear Energy & Electricity happening in real Customers pay the utility for the time. It helps the electricity that they use. Meters keep utility find and fix track of how much electricity travels problems like from a power company’s wires into our damaged power homes, businesses, schools, and factories. lines quickly. The company either sends a worker to A smart grid read the meter or newer meters send a can also tell signal through the power lines to the the power power company that shows how much company when each customer has used. Then the power more electricity company sends each user a bill. The smart grid communicates is needed to meet with other wireless equipment demand. This helps How do utilities plan for the the way smart phones do. utilities be more future? efficient. It also helps Because an electric utility must serve customers choose to the needs of the public, the people who use more electricity at when power manage it must plan carefully so they can rates are cheaper. produce enough electricity. Decisions made today must predict the public’s need for electricity in the Why do we have to future. These decisions can be pay for electricity? difficult. It takes from 5 to 15 The electric industry years to build a new fossil fuel must build power plants, or nuclear plant. It also takes run them, buy fuel time to build a power plant for the plants, string that uses renewable energy, wires or bury them like a dam, solar project, or a underground to every . Because it can take home and business, and so long, utilities must act on pay workers to do all the predictions of what customers jobs that must be done. Meters measure a customer’s will need in the future. As you can imagine, use of electricity so that bills are all that takes a lot of accurate. money.

Lesson 2 Electricity Basics 17 Lesson 2 ELECTRICITY BASICS


Electricity is our most versatile form of Companies that sell electricity are called energy. Electricity is created by the flow of utilities. Utilities are often regulated so tiny particles called electrons that have an that our electricity supply is steady and electrical charge. costs are fair.

At power plants, electricity is produced There are three main steps in getting by converting an energy source into electricity to customers – generation, electricity. In the United States, the transmission, and distribution. sources include fossil fuels, uranium, and Electricity is sent through the power water power. We also use solar power, grid to customers. Customers pay for wind, biomass, and geothermal energy. the electricity they use. New smart grid systems help utilities track the demand for Most U.S. power plants generate electricity and operate efficiently. electricity by heating water to produce steam and then use steam to turn the blades of a turbine attached to a generator.

18 The Harnessed Atom: Nuclear Energy & Electricity Lesson 3 ATOMS AND ISOTOPES

Introduction You’ve probably heard people refer to nuclear energy as “atomic energy.” Why? Nuclear energy is the energy that is stored in the bonds of atoms, inside the nucleus. Nuclear power plants are designed to capture this energy as heat and convert it to electricity. In this lesson, we will look closely at what atoms are and how atoms store energy.

TOPICS: Matter What are molecules, elements, What is an atom? Molecules and atoms? Molecules are made of even smaller parts, Elements To understand nuclear energy, it is which are called atoms. An atom is the Periodic Table important to first understand atoms, smallest part of any element that has all the The atom which are the building blocks of matter. properties of that element. Atoms are so Parts of an atom Isotopes small that it takes millions of them to make Unstable isotopes What do you suppose would happen a speck of dust. Scientists and if you took a lump of salt and discoveries began to break it up into smaller and smaller pieces? Sooner or later you would get pieces so small that you wouldn’t be able to see them. The smallest piece that is still salt is called a . Everything is made of molecules – sugar, salt, tables, chairs, and even the cells of your own body. However, all molecules are not alike. A molecule of sugar is different from a molecule of salt. Image Credit: Jon Reis But that is not the whole story. A molecule consists of two or more atoms bonded together. In the model built here, the black spheres represent carbon atoms. The connectors that join the spheres represent the chemical bonds.

Lesson 3 Atoms and Isotopes 19

Preliminary Working Draft - Not for Distribution Lesson 3 ATOMS AND ISOTOPES

+ +

Today, we know that at least 92 different kinds of atoms occur in nature. More Think about it... kinds of atoms have been made by scientists. Each of these different kinds of The word “atom” comes to us from a Greek atoms is a unique element. philosopher named Democritus. Around 420 BCE, Democritus wondered, “What is the smallest piece you could cut something like a Combining atoms of different elements – piece of gold into?” Although he did not have or atoms of the same element – forms a laboratory, he realized that at some point, molecules. The kind of molecule the gold would become too small to cut any depends on which atoms combine. This more. He called the smallest piece atomos, combining is called a chemical reaction. which means “indivisible,” or “cannot be In chemical reactions, atoms do not cut.” He proposed that all matter was made of these infinitely small particles that cling change. Instead, they combine with or together in different combinations to make separate from other atoms. things. Democritus couldn’t see atoms. But he understood that they must exist. For example, gold is an element. A bar In 1803, English chemist John began of pure gold contains only atoms of one to question ideas about structure of matter. element: gold. On the other hand, table He proposed an atomic theory that said salt is a combination of more than one • Elements are made of very small kind of atom. It is made of atoms grouped particles—atoms into molecules. A molecule of table salt • For each element, all the atoms have the has one atom of the element same size, , and properties • Atoms cannot be divided, created, or and one atom of the element chlorine. destroyed Another familiar example is water. A • Atoms combine to form chemical molecule of water has two atoms of compounds and one atom of oxygen. That is • In chemical reactions, the atoms in a compound rearrange or separate why chemists call water H2O. Dalton performed experiments and found Atoms are the basic building blocks of that matter seemed to consist of 35 elements that he could identify. everything in the universe. They are the smallest particles of matter that still have all of the properties of an element.

20 The Harnessed Atom: Nuclear Energy & Electricity

Preliminary Working Draft - Not for Distribution What are the parts of an atom? Structure of As small as atoms are, they are made of an Atom

even smaller particles. There are three Nucleus basic particles in most atoms – , neutrons, and electrons. Neutron Protons carry a positive electrical charge Electron Shell (+). Neutrons have no electrical charge. Protons and neutrons together make a dense bundle at the center of an atom. The Rutherford-Bohr model provides a simple representation of the This bundle is called the nucleus. structure of an atom. Modern physics theory places the movement of electrons in a cloud of possible Electrons have a negative electrical charge around the nucleus. (-) and move around the nucleus. They are extremely small compared to the other picture on the puzzle was supposed to look parts of an atom. Normally, an atom has like, or even if it would make a picture. the same number of protons and electrons. Now imagine that jigsaw puzzles had not If the positively charged protons and the been invented yet. Could you solve it? negatively charged electrons are equal in number, they balance each other. As a result, That’s similar to the challenge that scientists the atom has no electrical charge. in the 1800s faced. They had discovered chemical elements but did not know how, We use the number of protons in an or if, they fit together. Many elements were atom to identify it. For instance, an atom missing. No one had ever tried to make a of oxygen has 8 protons in its nucleus. chart that organized the information. But Carbon has 6, 26, gold 79, 82, science is a process of organizing what we uranium 92, and so on. know to help us make sense of it all.

How was the periodic table Building on what was being learned about developed? atomic structure, Dmitri Mendeleev began Imagine discovering a few pieces of a sorting the known elements into categories. jigsaw puzzle, but not knowing what the His sorting became the foundation of the

If you could enlarge an atom to the size of a stadium, its nucleus would be about the size of a grape on the mid-field stripe. Electrons would be smaller than grains of salt whirling around the upper deck. And the rest of the stadium would be empty space.

Image Credit: University of Tennessee

Lesson 3 Atoms and Isotopes 21

Preliminary Working Draft - Not for Distribution Preliminary Working Draft - Not for Distribution Lesson 3 ATOMS AND ISOTOPES 2 10 18 71 36 54 86 Neon 118 103 8A [222] [262] [294] Lr Argon Xenon Ar Kr Lu 83.798 39.948 Krypton Ne Rn He Xe 20.1797 Lutetium 131.293 174.9668 4.002602 Ununoctium Lawrencium Uuo 9 I 17 70 35 53 85 F 117 102 [210] [294] [259] Iodine Cl At Br 35.453 79.904 Fluorine Astatine Yb Bromine Chlorine No Nobelium 173.054 Ytterbium Uus 126.90447 18.9984032 Ununseptium 8 16 52 34 84 69 S O 116 101 [293] [209] [258] Sulfur 78.96 Lv Te 127.60 32.065 Oxygen Thulium Se Po Tm Tellurium 15.9994 Selenium Md Livermorium 168.93421 Mendelevium 7 15 33 51 83 68 P N 115 100 [257] [288] Bi Er Erbium As Bismuth Sb Fermium 167.259 Nitrogen 14.0067 121.760 Antimony Fm 74.92160 30.973762 Uup 208.98040 Phosphorus Ununpentium Metal Transition Transition 6 Tin 67 14 32 82 50 99 C Lead 114 [252] 207.2 [289] Fl 72.64 Si Silicon Es Carbon Sn Pb Ge Flerovium Ho 12.0107 118.710 28.0855 Holmium Einsteinium 164.93032 Germanium Semi Metal 5 13 31 81 49 66 98 B Tl 113 [251] [284] In 162.5 3A 4A 5A 6A 7A Al Cf Indium 69.723 10.811 Gallium Dy Thallium Ga 114.818 Ununtrium Aluminum 204.3833 Uut 26.9815386 97 65 30 48 80 Rare Zinc Earth 112 [247] [285] 65.38 Tb 200.59 Zn Terbium Bk Cd Cn Hg 112.411 Cadmium Berkelium 158.92535 Copernicium

47 79 29 64 96 Gold 111 [247] Silver [280] 1B 2B 157.25 63.546 Copper Cu Ag Au Rg Gd 107.8682 Cm Gadolinium 196.966569 Roentgenium Non Metal 78 28 63 95 46 110 [281] [243] Nickel Ni Pt 106.42 Ds Eu Pd Platinum 195.084 151.964 58.6934 Europium Palladium Am Darmstadtium Gas Noble 77 27 45 62 94 Ir [276] 109 [244] 8B Cobalt 150.36 Mt Pu Rh Co 192.217 Rhodium Plutonium Sm Samarium Meitnerium 58.933195 102.90550 76 26 61 93 44 Iron [270] [237] 108 [145] 101.07 55.845 190.23 Fe Halogen Hs Ru Os Np Osmium Hassium Pm Ruthenium Promethium 25 43 75 92 60 [98] U 107 [272] Tc Uranium Re Bh Nd Bohrium 186.207 Rhenium 144.242 Mn Technetium 238.02891 Manganese 54.938045 Neodymium Metal Basic Atomic Number Atomic Weight 74 24 42 91 59 [271] 106 95.96 W Pr Cr 183.84 Pa Sg 51.9961 Tungsten Mo Chromium 140.90765 231.03588 Seaborgium Praseodymium Molybdenum Earth Metals Alkaline Periodic Table of the Elements Table Periodic 73 23 41 58 90 V 105 [268] Ta Th Cerium Ce Niobium Nb Db 140.116 50.9415 Tantalum Dubnium 1 Vanadium 92.90638 180.94788 232.03806 H 1.00794 Hydrogen Alkali 72 57 22 40 89 Metals Ti [267] [227] 104 Zr Rf 47.867 Hf La 178.49 91.224 Ac Titanium Actinium 138.90547 Lanthanum Rutherfordium

21 39 Y 3B 4B 5B 6B 7B See See Yttrium Sc 57-71 Below Below 89-103 Scandium 88.90585 44.955912 Lanthanides 4 12 20 38 56 88 2A [226] 87.62 Sr Barium 40.078 Ca Be Ba Ra Calcium 137.327 24.3050 Mg Strontium 9.012182 Magnesium Lanthanides Actinides 1 3 37 87 11 19 55 K H Li [223] 1A 6.941 Fr Lithium Cs Cesium Sodium Na Rb 1.00794 85.4678 39.0983 Francium Rubidium Hydrogen 22.98976 132.9054519 The Periodic Table of the Elements tells the names, symbols, and number of protons in each element. It also shows the relationships of the Elements tells names, symbols, and number protons in each Table Periodic The among the elements. Elements are placed on table in order of their atomic number and are arranged by properties.

22 The Harnessed Atom: Nuclear Energy & Electricity

Preliminary Working Draft - Not for Distribution Periodic Table. By 1869, he The isotopes of an element had grouped elements by H have the same chemical common properties. For He properties, but they may differ example, elements with in their nuclear properties. the smallest relative atomic mass went into the far left What are stable and column. As he learned more Au unstable isotopes? about the chemical properties of Some proton-neutron the elements, Mendeleev grouped combinations are more together metals, gases, and non-metals. His stable than others. Those that are stable later tables even left gaps where Mendeleev do not change. Those that are unstable suspected an element was missing, but he will change at some time. didn’t know what it was yet. By the early 1890s, he and others had identified about 80 What happens if you pull a rubber band elements. to its limit? It will break, and the energy that was holding it together will be Today the Periodic Table includes 118 suddenly released. elements. Most occur in nature. But those with an atomic number higher than 92 As you just learned, the isotopes of (uranium) were made by scientists. In the an element have different numbers of future, the Periodic Table will likely continue neutrons in their centers. Some of these to change based on new discoveries. isotopes are like rubber bands that are stretched too far. We call these elements What is an ? unstable isotopes. They break and change The nucleus in every atom of an element instantly to a different . always has the same number of protons. For example, oxygen always has eight protons. However, the number of neutrons may vary. The different numbers of neutrons determine isotopes of the element.

To show which isotope of an element we are talking about, we total the number of protons and neutrons. Then we write the sum after the chemical symbol for the element. For example, in the nucleus of one isotope of uranium there are 92 protons and 143 neutrons. We refer to it as uranium-235 or U-235 (92 + 143 = 235). A second isotope of uranium, which contains three additional Isotopes of an element are kind of like siblings neutrons, is uranium-238 or U-238 (92 + in a family. Although siblings share many genetic

The Periodic Table of the Elements tells the names, symbols, and number of protons in each element. It also shows the relationships of the Elements tells names, symbols, and number protons in each Table Periodic The among the elements. Elements are placed on table in order of their atomic number and are arranged by properties. 146 = 238). characteristics, each child is unique.

Lesson 3 Atoms and Isotopes 23

Preliminary Working Draft - Not for Distribution Preliminary Working Draft - Not for Distribution Lesson 3 ATOMS AND ISOTOPES

Scientists observe that the elements do disintegration of radio elements, an this to become more stable. Everything enormous amount of energy could be in the universe seeks these lower, more obtained stable energy levels. from a small When a stretched rubber band breaks, amount of you can’t see its energy, but you can see matter.” the effect on the rubber band, which The shoots across the room. following year, Albert Sometimes similar things happen when Einstein unstable isotopes break down and new proposed bonds are formed. Energy is released. And his famous although all atoms are extremely small, the theory Image Credit: NASA energy holding together their centers is about the relationship between energy the strongest force known in nature. It is and matter: E=mc2 which means “energy called strong force. When the strong force equals mass times the of light is broken and a new bond is formed, the squared.” This is a huge number. If energy that is released is vast. correct, it confirmed that a vast amount of energy was contained within the atom. How was the energy of atoms discovered? Scientists released energy from the As scientists from around the world nucleus by splitting atoms about 20 years continued their experiments, they later. Experiments by Italian Enrico realized that the atom held large Fermi and a team of scientists surprised amounts of energy. In 1895, German everyone, even Fermi himself. When he physicist Wilhelm discovered bombarded uranium with neutrons, he that an invisible energy was given off expected it to become heavier. Instead, by an electrical current inside a vacuum the resulting elements were lighter in tube. He called this unknown energy mass. German scientists Otto Hahn an “x ray” because it had no name. In and Fritz Strassman also fired neutrons 1896, French physicist Henri into uranium and were surprised to find observed that uranium gave off a lighter elements, like barium, in the similar energy. French chemist Marie leftover materials. Hahn and Strassman studied these “uranium rays” and worked with Lise Meitner, from Austria. discovered what they were: radioactivity. She observed that in her experiments, She realized that the energy came from the mass of lighter elements almost, within the atom itself. but not quite, equalled the total of the uranium mass. Meitner used Albert In 1904, British physicist Ernest Einstein’s equation E=mc2 to show that Rutherford recognized that, “If it were lost mass had changed into energy. ever possible to control the rate of

24 The Harnessed Atom: Nuclear Energy & Electricity

Preliminary Working Draft - Not for Distribution Summary

Atoms are the smallest units of matter Stable isotopes do not change. Unstable that have all the properties of an element. isotopes will change at some time. Atoms combine to form molecules. Atoms are composed of smaller particles known The energy that holds the nucleus of an as protons, neutrons, and electrons. atom together is the strongest force known in nature. Protons have a positive electrical charge, neutrons have no electrical charge, and The Periodic Table of the Elements electrons have a negative electrical charge. gives the names, symbols, and number of Protons and neutrons together form protons for each element. the nucleus or central mass of the atom. Electrons move around the nucleus. Many scientists have contributed to our knowledge of elements and atoms. They The nucleus of each atom of a specific have come from many countries and have element contains the same number of included both men and women. Some protons, but the number of neutrons may have been honored by having elements vary. Isotopes of an element are identified named after them. by adding the number of protons and neutrons together and writing the sum next to the chemical symbol for the element.

Lesson 3 Atoms and Isotopes 25

Preliminary Working Draft - Not for Distribution Preliminary Working Draft - Not for Distribution Lesson 4

Introduction In the last lesson, we learned that unstable isotopes emit energy as they become more stable. This energy is known as radiation. This lesson will explore forms of radiation, where radiation is found, how we detect and measure radiation, what sources of radiation people are exposed to, whether radiation is harmful, and how we can limit our .

TOPICS: Types of radiation What is radiation? Because we cannot see, feel, hear, smell, Non-ionizing Radiation is energy moving through or taste ionizing radiation, no one knew it Ionizing space in the form of waves and particles. existed until 1895. But it was here all along. Forms of ionizing radiation Radiation is everywhere – in, around, and Since its discovery, radiation has been one Alpha particles above the world we live in. It is a natural of the most thoroughly studied subjects Beta particles Gamma rays energy force that surrounds us. It is a part in modern science. Scientists have found Radiation of our natural world that has been here important uses for ionizing radiation. They Decay chain since the birth of our planet. have also studied its effects on human health. Half life Dose Radiation Radiation can be described as non- What are the forms of ionizing Measurements ionizing or ionizing. Non-ionizing radiation? Sources of radiation radiation does not have enough energy to Ionizing radiation includes the alpha and Average exposure knock electrons from atoms as it strikes beta particles and gamma rays emitted them. Sunlight, radio waves, and cell from radioactive materials. Cosmic phone signals are examples of non-ionizing radiation that reaches the Earth from radiation. However, it can still cause harm, outer space is ionizing. Ionizing x-ray like when you get a . radiation is produced by x-ray machines.

Ionizing radiation is the type of radiation Gamma rays, x-rays, and cosmic rays are most people think of when they hear the waves of pure energy, without mass or word radiation. Ionizing radiation can charge. They appear at the high knock electrons from an atom, creating (high energy) end of what we call the electrically charged particles called . .

Lesson 4 Ionizing Radiation 2727 Lesson 4 IONIZING RADIATION Spectrum Electromagnetic X-rays, gamma rays, and cosmic rays are waves of pure energy. They are part of the electromagnetic spectrum that also includes radio waves, visible light, They gamma rays, and cosmic rays are waves of pure energy. X-rays, electrons off molecules and cause them to become “ionized.” they can knock and light. Because they are higher energy frequency,

28 The Harnessed Atom: Nuclear Energy & Electricity The spectrum also includes non-ionizing radiation (radio and television Types of Ionizing Radiation waves, , light, etc.) : at the lower frequency (lower - easily stopped energy) end. - least penetrating

How does ionizing : radiation deposit - much smaller energy? - more penetrating Because it can knock electrons and x-ray: - pure energy with no mass from the atoms and molecules - most penetrating in its path, ionizing radiation can cause chemical changes in living cells. However, the types of ionizing radiation are different in how much they neutral atom or molecule penetrate and deposit energy Alpha, beta, and gamma are ionizing radiation. The distance each can through . travel is limited by how it interacts with other atoms.

Alpha particles are relatively less energy along their paths. Lead, water, large and carry a double positive charge and stop gamma radiation. (++). They are not very penetrating and a piece of paper or your skin can stop them. Where does radiation come from? They travel only a few centimeters but Some unstable isotopes become more deposit all their along their short stable by emitting or shooting out energy paths. In delicate tissue, alpha can do a rays similar to x-rays. Others may emit large amount of damage. particles from their nuclei and change into different elements. The rays and particles Beta particles (electrons) are much unstable isotopes shoot out are radiation. smaller than alpha particles. They carry a Substances that give off radiation in this single negative charge (-). They are more way are radioactive. penetrating than alpha particles, but thin aluminum metal can stop them. They can is the process of travel several meters but deposit less energy isotopes emitting particles or rays from at any one point along their paths than an atom’s nucleus to become more stable. alpha particles. An unstable isotope will eventually decay into a stable element. However, this Gamma rays are waves of energy without process may take many steps and a long mass or electrical charge. They can time. These steps are called a decay chain. travel 10 meters or more in air. This is a For example, the isotope uranium-238 long distance compared to alpha or beta transforms into more than 15 different particles. However, gamma rays deposit isotopes before it becomes stable lead-206.

Lesson 4 Ionizing Radiation 29 Lesson 4 IONIZING RADIATION

What is half-life? Half-lives of Some Radioisotopes decay at random, and it is Radioactive Isotopes impossible to guess which one will decay next. Yet, in a group of atoms, we can see a Americium-241 432.7 years pattern. We describe this pattern by using Fluorine-18 109.7 minutes the term half-life. The amount of time it Carbon-14 5,715 years takes for a given isotope to lose half of its radioactivity is known as its half-life. Hydrogen-3 () 12.32 years If a radioisotope has a half-life of 14 days, Iodine-131 8 days half of its atoms will have decayed within Iridium-191 4.9 seconds 14 days. In 14 more days, half of that remaining half will decay, and so on. Krypton-85 10.7 years Technetium-99m 6.01 hours

Some isotopes may change in the next Uranium-235 700 million years second, some in the next hour, some tomorrow, and some next year. Other Technetium-99m and fluorine-18 are useful in medical diagnosis because of their short half-lives. isotopes will not decay for thousands of years. Half-lives range from fractions of a What is radiation dose? second to several billion years. To measure how different amounts of ionizing radiation affect people, we use Decay Chain the term radiation dose. When you take , the effects of a dose depend on the type of medicine, the amount of the Uranium-238 medicine you take, the period of time in which the medicine is taken, and how your Thorium-230 own body responds. Two aspirin may cure your headache. Twenty aspirin in a week Radium-226 may cure ten headaches. But 20 aspirin taken all at once could do serious damage. Radon-218 Another example to think about is your Bismuth-214 exposure to the non-ionizing radiation from the Sun’s rays. If you spend a short Lead-206 time in the Sun each day, or limit your exposure by wearing sunscreen and Here are some of the steps in the decay clothing, your skin will get less damage chain of uranium-238. All steps are not Uraniumshown. slowly decays to lead. It happens in a than if you spend an entire day on the chain of events called a decay chain. Here are beach in just your bathing suit (ouch!). some of the steps in the uranium decay chain. The half-life of uranium-238 is 4.5 billion years. People who work with radiation limit their extra as much as

30 The Harnessed Atom: Nuclear Energy & Electricity possible. Your dentist may step out of the For instance, you may live a half mile away, room during your x-ray, for example. but you also live 2,640 feet from school, To minimize dose, workers can apply the 804 meters, or an 18-minute walk away. It’s rule of time, distance, shielding: the same with measuring radiation. • Decrease the time of exposure The unit most often used to measure • Increase the distance from a source of ionizing radiation in the United States is radiation millirem (mrem). The international unit • Increase shielding with dense material is millisievert (mSv). Both measure the like lead or concrete risk that the ionizing radiation will cause tissue damage in a person. One millisievert Because we cannot detect radiation with equals one hundred millirem (1 mSv = 100 our senses and because exposure to too millrem). much radiation is harmful, we use a special We use the curie (Ci) or becquerel (Bq) to symbol to warn us when measure the amount of radioactivity in a radioactive materials substance. We use the or (Gy) to are present. We put the talk about the energy in radiation absorbed symbol on packages of by a person. radioactive materials when we ship them by truck, train, plane, What does radiation do? or ship. We also put the symbol on doors Scientists have studied the effects of to rooms or areas where we use or store radiation for almost a century. High radioactive materials. You have probably doses are well understood. If an exposure seen the symbol if you have had an x-ray. is very high and happens quickly, it is dangerous. Radiation exposures of over How do we measure radiation? 1,000 millisieverts (100,000 millirems) Scientists use different units to measure cause radiation sickness. Very high radiation depending on what they want to exposures over 5,000 millisieverts (500,000 measure. If a friend asks how far it is from millirem) received all at once usually cause school to your home, you can answer the death. Fortunately, exposures this high are question several different ways. extremely rare. Measurements of Radiation What is measured Traditional unit International Unit (SI)

Total amount of radioactivity contained in a source curie (Ci) becquerel (Bq) 37 billion Bq = 1 Ci Radiation dose absorbed by a person rad gray (Gy) (amount of energy deposited in human tissue) (radiation ) 1 Gy = 100 rad

Biological effect of exposure to radiation rem (radiation equivalent man) (Sv) or millisievert (dose equivalent) or millirem (mrem) (mSv) 1 Sv = 0.l rem 1 mSv = 100 mrem

Lesson 4 Ionizing Radiation 31 Lesson 4 IONIZING RADIATION

Where Our Exposure to Ionizing Radiation Comes From amount received all at once before doctors can detect any harmful effects on a person.

Some scientists believe that any amount of radiation may have a harmful effect. However, most scientists believe that 2.98 mSv 3.1 mSv low levels do not have much effect on Medical diagnosis Background people. If radiation exposure is low, or the and treatment radiation in nature (48%) (50%) radiation is received over a long period of time, the body repairs any damage. Even so, sometimes the body makes an incorrect repair. If this happens, there is a possibility of a delayed effect that doesn’t show up for years. can be one delayed effect.

0.12 mSv 0.006 mSv Consumer Working at Where does our exposure to products jobs radiation come from? (2%) (0.1%) In the United States, the average person Adapted from NCRP Report No. 160, Ionizing Radiation Exposure of the Population of the United States, March 2009. receives about 6.2 millisievert (620 millirem) a year. About half of this is from People who work in industry or medicine natural radiation and half is from medical are permitted to receive up to 50 millisievert procedures. (5,000 millirems) a year. It takes 10 times this

Radiation Moves Through Our Environment

Air Rain Cosmic radiation Dust and dirt Rocks

Building materials

Breathing Crop uptake Ground water

Our bodies

Irrigation Food, milk, crop Ground ingestion water contact Livestock

Eating fish and other seafood

Everything around us exposes us to small amounts of radiation.

32 The Harnessed Atom: Nuclear Energy & Electricity Terrestrial Radiation by Region

Northwestern, Eastern, Central, and Far Western Areas Range: 2.5 to 5.5 millisieverts/year (25 to 55 millirems/year) Average: 0.3 millisieverts/year) (30 millirems/year)

Colorado Plateau Area Range: 5.5 to 10 millisieverts/year (55 to 100 millirems/year) Average: 0.63 millisieverts/year AK (63 millirems/year) Atlantic and Gulf Coastal Plain Range: 0.1 to 2.5 millisieverts/year (10 to 25 millirems/year) Average: 0.16 millisieverts/year (16 millirems/year) HI

The average yearly dose of ionizing The main natural sources of radiation are radiation in the United States is • Terrestrial radiation from the rocks increasing. That’s because we use radiation and around us much more often as a tool in medicine. As • Cosmic radiation from space imaging improves, doctors are • Radon in the atmosphere using x-rays and computed tomography (CT) scans more often for diagnosis. • Internal radiation, the radioactive Doctors are also using radiation to treat elements in our bodies, mainly from diseases such as cancer. what we eat or drink The sum of our exposure from these What is ? sources is called background radiation. Let’s look more closely at where we find radiation. Everything in the world is What is terrestrial radiation? radioactive and always has been. The ocean Terrestrial radiation is background we swim in, the mountains we climb, the air radiation that comes from the Earth. we breathe, the we eat, and the water About 7 percent of natural background we drink all us to small amounts of radiation is terrestrial radiation that comes radiation from nature. This is because there from elements like potassium, uranium, are unstable isotopes that emit ionizing and thorium. Most soils around the world radiation everywhere on Earth. contain at least small amounts of these elements. These elements constantly decay and emit radiation.

Lesson 4 Ionizing Radiation 33 Lesson 4 IONIZING RADIATION

affects your exposure from space radiation. How close you live to the equator also affects your dose. In Honolulu (at sea level and near the equator), the average annual dose from space radiation Crack is 0.26 millisievert (26 millirem). In Denver, Loose-fitting Floor Drain pipe (farther from the Sump equator and higher altitude) the dose is Radon 0.52 millisievert (52 millirem). This means a ski instructor at a mountain resort will receive more background radiation than a fisherman at sea level. Taking a jet flight also results in exposure to space radiation. However, there is no evidence of Radon gas travels from the soil up into buildings. increased radiation health effects for people who live at high altitudes or for people, like airline pilots, who fly often. The average dose to a person in the United States from terrestrial sources is What is radon? about 0.2 millisievert (200 millirem) per Radon is a radioactive gas that comes year. However, average exposure varies from the natural decay of uranium throughout the country, taking into account found in nearly all soils and water. It soils and the populations of different has no color, odor, or taste. It can get regions. For example, on the coastal plains into our buildings through cracks in the of the Atlantic and Gulf regions, the foundation. When this happens, it can average annual dose is lower than it is in the build up indoors. Radon gas can damage mountains in the western United States. lung tissue if we breathe too much of it. Simple tests can help you check a building What is space radiation? or home for high radon levels. Space radiation comes from solar particles and cosmic rays from outer space. It What is internal radiation? accounts for about 11 percent of the total Natural radiation is also found in plants, dose you get from background radiation. animals, and people. After all, living things This radiation is filtered by the Earth’s are made entirely of atoms of the elements atmosphere, so the elevation where you live from Earth, including such elements

34 The Harnessed Atom: Nuclear Energy & Electricity as potassium and carbon. from medical uses like x-rays, CT scans, Some are radioactive. The and treatments for cancer that use radiation we receive from radiation. But human-made sources elements inside our bodies include consumer products, such is called internal radiation. as smoke detectors. Americans get about 2.68 millisieverts (268 millirems) Other human-made sources are of radiation each year from the related to technology. We get a trace food we eat, what we drink, and elements amount of radiation from the nuclear we breathe in. Of course, this number power industry (0.1 percent of our varies depending on what we eat or exposure). It also comes from naturally drink, where it is grown, and how much occurring radiation in coal, ash, and we eat. However, all foods contain some smoke from coal- radioactive elements, and certain foods – fired power plants. bananas and Brazil nuts, for example – Other examples contain higher amounts than other foods. include increased These are not harmful, and potassium and terrestrial carbon are essential for our health. radiation from disturbing soils during construction What are some human-made or road building and sources of radiation? fertilizers made from . Building We get additional radiation from products materials, such as bricks and stone, also that use radiation. You already know emit natural background radiation. So our that almost half of our average annual homes, schools, factories, and businesses exposure to radiation (48 percent) comes are all sources of background radiation.

Lesson 4 Ionizing Radiation 35 Lesson 4 IONIZING RADIATION


Radiation is energy moving through space There are also human-made sources of in the form of waves and particles. It is a radiation. These include medical uses such part of natural world and has been since as x-rays and CT scans and some products the beginning of our planet. It can be like smoke detectors. The average yearly described as non-ionizing (low energy) or dose of ionizing radiation for a person in ionizing (high energy). Some important the United States from all sources is 6.2 forms of ionizing radiation are alpha and millisieverts (620 millirems). Half comes beta particles, gamma rays, and x-rays. from background radiation (50 percent), 48 percent comes from medical uses, and Unstable isotopes change by emitting 2 percent comes from consumer products particles or energy rays in a process called and industry, including making electricity. radioactive decay. As an unstable atom decays, it changes to a different element. Because it can knock electrons from the Eventually, unstable isotopes decay to atoms and molecules in its path, ionizing stable elements. The half-life of an isotope radiation can cause changes in human is the amount of time it takes to lose half tissue. Most scientists believe low levels of of its radioactivity by decay. exposure to radiation have an insignificant effect on people. If exposure is low or the The main natural sources of ionizing radiation is received over a long period radiation we are exposed to are called of time, the body can usually repair itself. background radiation. Background However, if an exposure is high enough, it radiation includes can cause damage. Fortunately, exposures • Terrestrial radiation from the rocks and to large amounts are extremely unusual. soils around us People who work with radiation minimize • Solar particles and cosmic radiation their exposure using the rule of time, from space distance, and shielding: • Radon in the atmosphere • Decrease the length of time of • Internal radiation - radioactive exposure materials in our bodies mainly from • Increase the distance from a source what we eat, drink, and breathe in • Increase shielding

36 The Harnessed Atom: Nuclear Energy & Electricity Lesson 5 FISSION, CHAIN REACTIONS

Introduction We have learned how the nuclei of atoms store energy and how unstable atoms decay and release energy. How do nuclear engineers use this knowledge to help them harness energy to make electricity? The answer lies in being able to start a nuclear chain reaction in fuel inside a nuclear power plant and keep it going. In this lesson, we’ll look closely at nuclear reactions called fission. We’ll also learn how uranium is processed from ore to fuel.

TOPICS: Fission What is fission? When a uranium-235 atom splits apart, Chain reactions When scientists began to understand many things happen. We end up with two Uranium fuel the that bind atoms together, they lighter-weight atoms of new elements, Mining wondered if a machine could be built to which are called fission products. Milling Enrichment harness this energy. A team of scientists Two or three neutrons are released. Fuel fabrication led by Enrico Fermi built a machine to And an enormous amount of

harness the energy within atoms in 1942 at kinetic energy is released, Neutrons the University of Chicago. The machine, mainly as heat. a reactor, caused uranium atoms to split in a process called fission. Fission releases energy from the nucleus of the atoms.

When a neutron strikes the nucleus Neutron of uranium-235, the Energy nucleus becomes more unstable, U-235 vibrates, and then Fission splits apart. All this Product takes about a In a chain reaction, a neutron causes U-235 millionth of a an atom of U-235 to undergo fission, or split. second. This releases energy and two or three more neutrons, which then cause other U-235 atoms to split. This continues the reaction.

Lesson 5 Fission, Chain Reactions 37 Lesson 5 FISSION, CHAIN REACTIONS

What is a nuclear chain reaction? fissioning of billions of uranium-235 Splitting an atom apart releases a lot of atoms heats water, which produces steam. energy, especially considering its size. This steam turns turbines to generate But splitting one atom does not produce electricity. The major difference between enough heat to be useful. We need to a nuclear power plant and one that burns fission millions of atoms to get enough coal is the way the heat to make steam is heat to do work. produced. The rest of the nuclear power plant is very similar. How can we do that? The answer lies in the two or three neutrons that fly off when Where does uranium come from? the first atom is split. If these neutrons hit Uranium formed in the supernovae that other uranium-235 atoms, these atoms also created our about 4.6 billion fission, each releasing heat and two or three years ago. It was part of the material in more neutrons. Under the exactly right space that became the Earth. Uranium conditions, we can get millions of atoms is a dense metal element that holds a fissioning. When that happens, it gives off tremendous amount of energy in its enormous heat. This chain of events is nucleus. This element occurs in small called a nuclear chain reaction. amounts all over the world, even in

Keeping a chain reaction going is actually very difficult. This is because many of the neutrons that fly away from each fission will not hit another uranium atom’s nucleus. If more miss than hit, the chain reaction will quickly slow down and stop.

The heat we get from a chain reaction comes from breaking the strong force in the nucleus and forming new bonds. In this Uranium is found in rocks and soil around the world. Rock that process, a tiny amount of mass is contains 2 to 4 pounds of uranium per is called uranium ore. converted into energy (E=mc2). As fission products bounce off neighboring seawater. Rocks that contain uranium atoms, kinetic energy is converted to heat are called uranium ore. Typically, a ton by friction. of uranium ore contains 2 to 4 pounds of uranium. Before we can use uranium What is the fuel at a nuclear to generate electricity, we must mine it, power plant? separate it from the ore, and process it. The fuel at a nuclear power plant is Let’s look at the steps in taking uranium uranium-235. The heat produced by the from a in the Earth to .

38 The Harnessed Atom: Nuclear Energy & Electricity How is uranium mined? Workers can mine uranium ore in much the same way they mine coal, either in deep underground mines or in open-pit surface mines. They can use machines to dig the ore from the Earth. However, today, miners often take uranium from the ground by a process called in-situ . Workers drill into the rock and inject solutions that dissolve the uranium from the ore. Then they pump out the solution that contains the dissolved uranium from a second well. The end result of uranium milling is a dry, powder known as yellowcake. Mining any mineral alters the environment and disturbs the habitat of plants and What is enrichment? animals. To minimize damage and to Less than 1 percent of the atoms in protect the environment, when mining are uranium-235 atoms. ends, mining companies must replant and Most of the rest of the uranium atoms restore the land. This process is called are uranium-238. However, power plants reclamation. Federal, state, and local need uranium that is about 4 percent agencies enforce mining laws that help uranium-235. This means that before it protect mine workers and the environment. can be made into reactor fuel, we must increase the concentration of uranium-235 What is uranium milling? in a process called uranium enrichment. If miners remove the ore as rock, the uranium ore is crushed. Crushed ore is put How do we enrich uranium? in an acid. The acid dissolves the uranium Isotopes of uranium-238 contain but not the rock. The solution is dried, three more neutrons than isotopes of leaving a yellow powder called yellowcake, uranium-235. This gives them a tiny bit which is mostly uranium. The process of more mass. This tiny difference in mass removing uranium from the ore is called makes it possible to separate these two uranium milling. isotopes of uranium. We can make fuel richer in uranium-235. The leftover rock is known as mill tailings. Mill tailings contain other , Before uranium can be enriched, it is including the element radium. Radium gives purified and combined with fluorine at off a radioactive gas called radon. Uranium a conversion plant. This compound is mill tailings are disposed of by putting them uranium hexafluoride, also known by its back in the ground and covering them with chemical name, UF6. soil and clay to keep radon in and water out.

Lesson 5 Fission, Chain Reactions 39 Lesson 5 FISSION, CHAIN REACTIONS

Next, it is shipped to a facility where it uranium must be Centrifuge Enrichment is heated to a gas and pumped through taken to a fuel

barriers that contain extremely tiny holes fabrication plant UF6 Feed Enriched U-235 that act as filters. Because it has about where it is made 1 percent less mass, uranium-235 moves into reactor fuel. through the holes a bit more easily than At the fabrication uranium-238. By the time the gas has gone plant, uranium through thousands of filters, the percentage is pressed into of uranium-235 has enriched from less than solid, fuel Depleted 1 percent to about 4 percent. pellets. These U-235 fuel pellets can Gaseous Diffusion Enrichment withstand very high temperatures, Low Pressure much like ceramic Less High Pressure (U-235) tiles or oven-proof Feed Depleted UF6 cookware. Fuel

Low Pressure Enriched pellets are about More (U-235) Image Credit: USEC, Inc. 1 centimeter (3/8 inch) in diameter

In gaseous diffusion, uranium hexafluoride gas and about 2 is pumped through many filters called barriers. centimeters Each time the gas goes through a filter, the (3/4 inch) long. Motor concentration of uranium-235 gets slightly richer. Workers stack fuel Centrifuge enriches fuel by pellets in fuel rods. spinning uranium hexafluoride. Heavier uranium-238 moves A more energy-efficient process uses Then they bundle toward cylinder walls. Uranium-235 a centrifuge to enrich uranium. A fuel rods together collects near the center. centrifuge separates heavier materials from as fuel assemblies. lighter ones by spinning them. UF6 gas is placed in a cylinder, which then rotates How much energy is in uranium at a very high speed. The rotation makes fuel? the heavier uranium-238 molecules move Energy in uranium is extremely concentrated. toward the outside wall while the lighter A uranium fuel pellet weighs less than 14 uranium-235 molecules collect near the grams (0.5 ounce), which is less than an center. This process is repeated until the empty aluminum soft drink can. Each pellet percentage of uranium-235 has increased can release as much energy as 477 liters (126 to about 4 percent. gallons) of oil, 1 metric ton (2,200 pounds) of coal, or 2.3 metric (5,000 pounds) of How is the uranium prepared for wood. This means that there is a very large the reactor? amount of energy available to generate heat We can’t just put uranium into the reactor the and make electricity. way we pour coal into a furnace. Enriched

40 The Harnessed Atom: Nuclear Energy & Electricity Fuel Equivalents Each fuel rod holds about 200 fuel 1 uranium fuel pellet pellets and is about 4 meters long. has as much energy A single fuel rod does not contain available as... enough uranium-235 for a fission chain reaction. So, depending on the 3 barrels 1 metric ton design of the power plant where they of oil of coal (477 liters or (2,200 lbs) will be used, 63 to 264 fuel rods are 126 gallons) bundled together in a fuel assembly. A reactor core has 200 to 800 fuel assemblies. Nuclear plants replace one-third of their fuel assemblies about 1 uranium every two years as the uranium-235 fuel pellet gets used up.

2.3 metric tons 481 cubic meters of wood of natural gas (5,000 lbs) (17,000 cubic feet)

Fuels have different energy content. Less uranium is required to produce electricity.

Fuel Pellets Fuel Rods Fuel Assemblies Workers stack uranium fuel pellets inside fuel rods and group the fuel rods in fuel assemblies.

Think about it...

Fission gives off energy when the heaviest elements are split. Another kind of reaction, fusion, gives off energy when the lightest elements are combined, or fused together. When two hydrogen atoms fuse to form a helium atom, a huge amount of energy is released. Thanks to the pioneering work of Albert Einstein, the formula E = mc2 tells us exactly how much energy the fusion reaction releases. Fuel used for fusion is abundant and can be taken from sea water. But there are huge challenges to harnessing this power. The greatest challenge is how to heat the hydrogen fuel to 100 million degrees Celsius (180 million degrees Fahrenheit) and confine it long enough for fusion to occur. So far, scientists have been able to maintain a controlled, continuous fusion reaction for only fractions of a second.

Lesson 5 Fission, Chain Reactions 41 Lesson 5 FISSION, CHAIN REACTIONS


Fission occurs when a neutron strikes Less than 1 percent of the atoms in the nucleus of a uranium-235 atom, uranium are uranium-235. But power causing the atom to split apart. Two plants need uranium that is about new lighter- weight atoms, two or three 4 percent uranium-235. The uranium neutrons, and a lot of energy —­ mostly enrichment process raises the as heat — are released. If the neutrons concentration of uranium-235 based on that were released hit other uranium-235 the fact that uranium-238 atoms have atoms, these atoms may fission. This a tiny bit more mass than uranium-235 way, millions of atoms can be made to atoms. We enrich uranium by using fission. This sequence of events is called a gaseous diffusion or by using centrifuges. nuclear chain reaction. In addition to fission, or splitting atoms The fuel for nuclear power plants is of heavy elements, scientists are learning uranium, a dense metal found in rocks and how to control another type of nuclear soil around the world. Rock that contains reaction called fusion. Fusion occurs 2 to 4 pounds of uranium per ton is when light atoms of hydrogen join known as uranium ore. Uranium is mined, together (or fuse) to create helium and milled, converted to a gas, enriched, and release a large amount of energy. So far, then made into solid ceramic pellets that scientists have been able to maintain a are stacked in fuel rods that are bundled controlled, continuous fusion reaction for together as fuel assemblies. only fractions of a second.

42 The Harnessed Atom: Nuclear Energy & Electricity Lesson 6 ATOMS TO ELECTRICITY

Introduction Most power plants make electricity by boiling water to make steam that turns a turbine. A nuclear power plant works this way, too. At a nuclear power plant, splitting atoms produce the heat to boil the water.

TOPICS: Inside the reactor How does splitting atoms How is the electricity produced? Heat produce electricity? The heat from fission turns water into Pressure Steam A nuclear power plant is built to produce steam. The mechanical energy from steam Fission control electricity. But splitting atoms, or fission, pressure turns a turbine. This spins a Fuel assemblies does not produce electricity directly. generator, which produces electricity. The Control rods Splitting atoms produces heat. At a way heat energy is changed into electrical Pressure vessel power plant, heat energy is converted to energy in a nuclear power plant is the mechanical energy that is then converted same as in a coal power plant. Turbine Generator to electrical energy. Condenser

Transmission Tower

Pressurizer Steam Generator Reactor Generator


Cooling Tower Condenser

Lesson 6 Atoms to Electricity 43 Lesson 6 ATOMS TO ELECTRICITY

A is What are control rods? Control basically a machine Rods The control rods help regulate, or that heats water. Like control, the rate of fission. Control other large power rods are made of cadmium or plants, nuclear plants boron metal. They slide in and have specialized pipes, Fuel out of the reactor core and act like electrical equipment, Assemblies sponges for neutrons. and buildings. They are built to extremely When control rods are inserted high standards so that in the fuel, they absorb neutrons. they will work reliably Keeping control rods in the fuel and produce electricity Water prevents a fission chain reaction. (Coolant that customers need. Moderator) Pulling the control rods out of the fuel allows the reaction to begin. Pressure Utilities use two Vessel different types of Who controls the control rods? nuclear reactors in the The fuel assemblies, control rods, United States. One is and coolant make up the reactor’s Highly trained operators work in the pressurized water core. The core is surrounded by a the control room. They monitor the reactor, and the other massive steel pressure vessel. reactor with the help of computers is the boiling water and sensors. The operators in the reactor. Both use ordinary water and work control room are the “brain” of the power in a similar way. In this lesson, we use a plant. To start the reactor, they slowly pull pressurized water reactor to explain the the control rods out of the core. Without science of how nuclear power plants work. the control rods to absorb neutrons, fission begins and produces heat. Where does fission take place? Fission takes place in the fuel sealed inside the core of a nuclear reactor.

Uranium fuel assemblies form the core of the reactor. A reactor core has 200 to 800 fuel assemblies, depending on its design. Because uranium has so much energy, the fuel in the core lasts about three to five years. To maintain the plant, utility workers turn off the reactor about every 2 years and replace one-third of the fuel, rather than changing it all at once. This helps to schedule regular maintenance on the plant and keeps the power supply steady. Nuclear power plant operators use computers and sensors in the control room to monitor the reactor.

44 The Harnessed Atom: Nuclear Energy & Electricity Operators monitor the temperature in neutrons when they are moving more the reactor closely. As the temperature slowly. Using water to slow the neutrons in the core rises, they adjust the reactor down allows enough neutrons to be to keep the rate of fission constant so captured by the uranium fuel for a chain the temperature stays at about 315o C reaction to occur. (600o F). If there is any sudden change in temperature or pressure, the reactor What is a pressure vessel? automatically shuts down by all The reactor is surrounded by a huge steel the control rods into the fuel. It takes only pressure vessel. Its walls are over 20 cm seconds to stop the nuclear chain reaction. (7.87 inches) thick, and it weighs more than 300,000 What is the coolant and kg (331 moderator? tons). It is Water is the reactor’s coolant. Water filled with circulates around the fuel to transfer heat the coolant from the core. Water also keeps the core from water that getting too hot. protects the reactor core Water serves by removing another heat. purpose in Pressure a reactor. vessels are It is also a machined to The is cast moderator. the highest from solid steel 20 cm (9 inches) Passing standards. thick. through Every square water slows centimeter the neutrons is x-rayed to make sure there are no hidden down, or defects inside the metal. The steel vessel “moderates” can withstand very high temperatures and their speed. pressure. This helps make fission The entire reactor system is surrounded possible. by a containment building made of thick concrete that is reinforced with steel. This It is easier for building protects the reactor from problems Just as it is easier to catch uranium-235 outside, and it protects the environment in a ball that is thrown softly, case of a problem in the reactor. neutrons are more likely atoms to to be captured and cause capture fission when they are not moving too fast.

Lesson 6 Atoms to Electricity 45 Lesson 6 ATOMS TO ELECTRICITY

The reactor is surrounded by a massive concrete and steel reinforced containment building 2 to 3 meters (6 to 10 feet) thick. This picture shows the two containment buildings for reactors at St. Lucie plant in Florida.

What is heat cannot expand. Power plant transfer? operators use this pressure to The science of how heat water to 315° C (600° F) heat moves is called and keep it a liquid. Higher Heat thermodynamics. The temperatures make the system more energy efficient. show that when heat is added to a system, some The power plant has three of the heat moves, or separate loops of piping. transfers, to the systems When you pour hot cocoa Water in one loop does not around it. Heat moves into a mug, the mug quickly mix with water in the other from hotter systems becomes warm. This is because heat always flows from hotter loops. However, the heat to cooler ones. This materials to colder ones. transfers from one loop to scientific law helps us another. How? Transmission understand how we move Tower the heat energy produced inside the reactor. First Loop

How does the heat make steam? Pressurizer Steam Heat moves from the hot fuel to the cooler Generator Control Rods water that surrounds it. The water gets hot. Generator Normally, water boils when it reaches 100° C (212° F). When water boils, it turns into steam. Steam is water in the form of a gas rather than a liquid. Gases take up more than liquids. Turbine Engineers design a pressurized water reactor so that there is not space for the hot water to turn into steam. The heated water builds up pressure because it Pressure Vessel Condenser Cooling Tower 46 The Harnessed Atom: Nuclear Energy & Electricity Containment Building The huge blades of the turbine are generator changes the mechanical energy of spun by steam. the spinning turbine into electrical energy. The turbines are attached to the generators. The generator works by rotating a coil of Generators convert wire inside a magnetic field. This causes the mechanical energy of the electrons to move in the wire. spinning turbines into electricity by What happens after steam spins rapidly spinning a the turbine? coil of wire inside a magnetic field. As steam turns the blades of the turbine, it loses much of its mechanical energy. The temperature and pressure drop. Before it In a pressurized water reactor, superheated can be used again, the steam must be cooled water in the first loop flows through tubes back into water. Then it can be pumped in the steam generator, making them very back through the second loop to be re- hot. Heat energy is transferred as water in heated and turned back to steam to build up the second loop touches these hot tubes. pressure, starting the cycle again. This causes the water in the second loop Transmission to boil, building pressure as the water Second Loop Tower expands from liquid to vapor. The steam pressure provides mechanical energy thatPressurizer Steam Generator can be used to do work. Control Rods Generator How does the steam drive turbines to make electricity? Steam pressure blows across the blades of the turbine and spins it. A turbine works like Turbine a pinwheel with many blades. The spinning turbine is attached to a generator. ThePressure Vessel Cooling Tower Containment Building Condenser

How does the condenser work? Cooling the steam back into water is the purpose of the third loop. It starts with the condenser, which is located below the turbine. In the condenser, steam from the second loop flows over tubes filled with cool A generator at a large power plant is about twice the water from a lake, river or ocean. The steam size of a school bus. It can produce enough electricity transfers its heat to the third loop. The water to supply a city of half a million people. does not mix. Only the heat is transferred.

Lesson 6 Atoms to Electricity 47 Lesson 6 ATOMS TO ELECTRICITY

Transmission Third Loop Tower

Pressurizer Steam Generator Control Rods Generator


Pressure Vessel Cooling Tower Condenser A glass of ice waterContainment in the summer Building is a model of how a condenser works. If you pour ice water into a glass, beads of water form on the Heat transfers from the water into the air. outside. The glass seems to be sweating. What Some of the water evaporates. The warm, is going on? We know water does not leak through the glass. The drops have come from moist air rises inside the tower. This pulls water vapor in the air. Heat energy from the in cool air from the bottom. A natural draft warm air has moved to the glass. Water begins to flow up and out of the top of the vapor in the air condenses into liquid when it loses heat energy. tower. The water is collected at the bottom of the cooling tower and used again in the third loop. Water that evaporates is replaced with more water from the river. Why do we remove the heat from the water in the third loop? Heat and moisture leave the top of the tower Warmer water might harm fish or plant life at about 16 km per hour if it were put back into the lake. So power (10 miles per hour) plant operators cool the water to protect into the atmosphere. Cooling Tower the environment. Laws require water to be What looks like smoke o o within 2.8 C (5 F) of the lake’s normal Moist air rises and coming from the top flows out the top. temperature before it is released. Therefore, of the cooling tower some nuclear and coal power plants use is really vapor from cooling towers to get rid of waste heat. Heat rises lake water. This by water has never convection. How does the cooling been near the tower work? Water falls by reactor. It is not gravity and loses heat. At 200 meters (656 feet) high, a cooling radioactive. tower is usually the power plant’s tallest structure. It is a giant, hollow concrete Cool air flows into cylinder. It sits on legs that allow air to the bottom. flow up under it. Inside the tower, warm lake water from the third loop is sprayed in the air and trickles down through the stair-stepped layers of the interior. Cooled water is recirculated or released to a river or lake.

48 The Harnessed Atom: Nuclear Energy & Electricity Summary

The way nuclear power plants produce to a very high temperature in the reactor heat energy through fission is unique. to the steam-generator. In the steam However, the way heat energy is changed generator, heat energy from the first loop into electrical energy is basically the same transfers to the second loop. as in a coal power plant. The second loop carries the heat energy At a nuclear power plant, fission takes as steam to the turbines and spins the place in the reactor. A reactor has four turbine’s blades. The turbines are attached main parts: to the generators, which change the • uranium fuel assemblies mechanical energy of the spinning turbine • control rods into electricity. From the turbines, water • water (the coolant and moderator) in the second loop goes to the condenser. • pressure vessel In the condenser, steam in the second loop The fuel assemblies, control rods, and is cooled when some of its remaining heat coolant/moderator make up the reactor’s transfers to the water in the third loop. core. The core is surrounded by the When it is cooled, the steam changes from pressure vessel. The entire reactor system a gas back into liquid water. is within the huge containment building. The third loop contains cooling water The reactor has separate loops of piping drawn from the river or lake. Because that use water to move heat energy. Water heated water could harm the environment, in these loops never mixes together. water in the third loop is pumped to the However, heat energy moves from one cooling tower where heat is removed. loop to another. Some of the water evaporates and leaves the cooling tower as water vapor. Most is In a pressurized water reactor, the first used again in the third loop. loop carries water that has been heated

Lesson 6 Atoms to Electricity 49


Spent Fuel

Low-level Introduction Waste This lesson takes a look at the waste from electricity production at nuclear power plants. It considers the different types of waste generated, as well as how we deal with each type of waste.

TOPICS: If all the electricity Waste What is waste? waste from other industries. you used in your Types of radioactive In our day-to-day living, we make a lot of The problem is that some lifetime was waste generated by Low-level waste trash. Think of how much garbage your nuclear power plant wastes nuclear power High-level waste family collects in one week. Think of how are radioactive. This means plants, your share of the highly Disposal much trash you have from just one visit to that disposing of the waste Transporting waste would fit in a Reprocessing a fast-food restaurant. It probably includes requires special care to soda can. Waste isolation wrappers, bags, straws, drink containers, and protect workers, the public, Decommissioning leftover food. Industries also have trash each and the environment. time they do or make something. These leftovers are called by-products or wastes. How do we decide the way to dispose What is nuclear waste? of waste? Like all industries, nuclear power plants When you finish your produce wastes. One of the main concerns lunch in the school about nuclear power plants is getting rid of cafeteria, do you just throw the wastes safely. your tray and everything on it in a pile for someone else to deal with later? Probably The problem with wastes at nuclear plants not. There is a place for your tray, another is not the amount they make, which is quite place to sort dishes, and a bin for the small in comparison with the amount of silverware. Your trash goes in the garbage

Lesson 7 Waste from Nuclear Power Plants 51 Lesson 7 WASTE FROM NUCLEAR POWER PLANTS can, and there might even be separate places Many companies also use radioactive to put recyclables and compost. Why are materials and have low-level waste to dispose there so many ways to get rid of what is of. These companies left after lunch? Because it is best to handle • Make smoke detectors different wastes in different ways. • Make instruments used to inspect for defects in highways, pipelines, and It is the same with wastes from a nuclear aircraft • Test and develop 80 percent of our power plant. There is a special way for new drugs disposing of each type of waste. The way it • Make supplies for medical procedures is disposed of depends on that use radiation or radioactive • How radioactive the waste is materials • The half-life of the waste • Make electricity at nuclear power • The physical and chemical form of the plants waste How do we dispose of What is low-level waste? low-level waste? In the United States, most low-level Low-level radioactive waste is sealed radioactive wastes comes from hospitals, in containers and shipped to a licensed research labs, industry, and nuclear power disposal site. The containers are put in the plants. Low-level waste includes items that ground and covered with soil. Then a “cap” have become contaminated with radioactive of soil and clay is put over the site. The cap material. This waste includes shoe covers, keeps the site dry. The site is monitored mops, water and air filters, cleaning rags, with sensors that can detect radiation. lab supplies, broken tools, gloves, and used Workers and protective clothing. regulatory Doctors perform agencies also 100 million medical regularly check procedures each year radiation levels that use radiation or at open and filled radioactive materials, trenches and and many of these around the site produce low-level boundary. waste.

Low-level radioactive waste is stored in containers and covered with soil.

52 The Harnessed Atom: Nuclear Energy & Electricity WA MT OR ND ME Richland MN


LA Barnwell Andrews FL AK


Northwest Compact Appalachian Compact Operating Southwestern Compact Atlantic Compact Low-level waste disposal sites Rocky Mountain Compact Central Compact Midwest Compact Southeast Compact Central Midwest Compact Texas Compact Not in a Compact

What is a low-level Where are low-level waste waste compact? disposal sites? By law, each State is responsible for Four States have licensed disposal sites. disposal of low-level waste from industries, They have agreements with compacts hospitals, utilities and research institutions or States not in a compact to accept within its borders. and dispose of low-level wastes. Private companies operate the sites and charge Instead of every State building its a fee for waste disposal. The sites are own site, most States have joined low- located at level waste compacts. They have legal • Barnwell, South Carolina agreements to share the cost of disposing • Richland, Washington of their low-level waste at one site in the • Clive, Utah • Andrews, Texas compact.

Lesson 7 Waste from Nuclear Power Plants 53 Lesson 7 WASTE FROM NUCLEAR POWER PLANTS

If spent fuel is recycled, then the waste that is left over is also considered high-level waste.

How is spent fuel stored? Spent fuel produces a lot of heat during the first year as radioactivity decays. The utility stores it near the reactor in a pool of water called the . The pool is typically 12 meters (40 feet) deep. Here, the A spent fuel pool allows spent fuel to cool and also water cools the spent fuel and also shields shields workers from radiation. the radiation. During storage, spent fuel becomes less radioactive through radioactive What is high-level waste? decay. After one year, 99 percent of the High-level waste is the highly radioactive radioactivity decays away. But it still remains by-product produced inside a nuclear radioactive for thousands of years. reactor. It can be either • Spent fuel (used fuel), or Some utilities use for • Waste materials remaining after spent spent fuel that has already been cooled in fuel is recycled the spent fuel pool. The casks are typically Every two years, about one third of the fuel steel cylinders that are either welded or assemblies in the reactor are replaced with bolted closed. The steel cylinder provides a new ones. Fuel that is removed from the leak-tight containment for spent fuel. More reactor is called spent fuel. Spent fuel can be steel, concrete, or other material surrounds considered high-level radioactive waste. each cylinder to provide radiation shielding.

How will we transport the waste? Eventually, utilities will ship spent fuel assemblies to a central storage site or a permanent repository. The utility will ship spent fuel in special spent fuel shipping casks. These dry storage casks hold assemblies that have cooled for at least one year.

54 The Harnessed Atom: Nuclear Energy & Electricity If you play a musical kilometers (70 miles) an hour, instrument in band, burning casks in jet fuel, sinking you probably take it them underwater, dropping them to school in a case from a crane onto a steel spike, and to keep it safe. The crashing a high speed train into a purpose of spent fuel cask on a trailer. In all of the tests, shipping cask is similar to the purpose the casks protected their contents, even of an instrument case. Both are specially though the trucks and trains were destroyed. made to protect their contents. A spent fuel shipping cask must also protect people and the What is reprocessing? environment from the radiation given off by Some parts of the spent fuel can be recycled the fuel it holds. Engineers design spent fuel and used again as reactor fuel. This is shipping casks with heavy shielding and thick called reprocessing. Spent fuel is taken walls that prevent radiation in the spent fuel out of a reactor when there is not enough assemblies from getting into the environment. uranium-235 to power a chain reaction. However, it is still 95.6 percent unused uranium, including 1 percent uranium-235. It also contains plutonium produced by the reaction. Both uranium-235 and plutonium can be recycled to make new reactor fuel.

At present, the United States has decided not to do nuclear fuel Transportation specialists carefully plan and manage fuel recycling. One reason is that a by- shipments for safety and security. product of reprocessing is plutonium, A spent fuel shipping cask must be strong and safeguards must be taken because the enough to withstand even the worst plutonium could be used to make weapons. transportation accidents. To be sure they work Another reason is that reprocessing is expensive. as they are supposed to, scientists and engineers have performed crash tests with these casks. If we do not reprocess spent fuel, then it They used high-speed cameras to study what will be treated as high-level waste. If we do would happen to the casks in a very serious reprocess spent fuel, there will still be some accident. The tests included slamming a truck high-level waste that requires disposal. and cask into a concrete barrier at over 113

Lesson 7 Waste from Nuclear Power Plants 55 Lesson 7 WASTE FROM NUCLEAR POWER PLANTS

How can we isolate high-level utilities store spent fuel at power plants as waste for thousands of years? other solutions are being evaluated. Nuclear technicians can seal high-level waste in heavy metal canisters and then store them What happens to a nuclear power deep underground in a geologic repository plant when it closes? drilled into a dry, stable rock formation. In A license to operate a nuclear power plant 1982, U.S. Congress passed the Nuclear lasts for 40 years. After that, the utility Waste Policy Act. This law called for a deep company can ask to renew its license for geologic repository to safely store or dispose 20 years longer, or it can shut down the of high-level radioactive waste. This geologic plant and decommission it. repository would be as much as 1 kilometer (.6 mile) underground with tunnels for During the years nuclear power plants storing waste. The Act required nuclear produce electricity, many parts become power plants to pay a fee for the cost of the radioactive. When the plant closes, the waste repository. radioactivity begins to decrease through the process of radioactive decay. With each In the years since it passed, there have passing year, materials at the reactor become been a number of changes to the Act. less radioactive. This means it becomes Yucca Mountain, in Nevada, was chosen easier to dismantle after 10 or more years by Congress as a site for a repository. In because the level of radioactivity is lower. 2010, work at that site was stopped. Today, What is the ? All of the steps involved in using uranium to make electricity are known as the nuclear fuel cycle. The fuel cycle begins with mining uranium ore and ends with nuclear waste This disposal. The fuel cycle includes all the steps to drawing shows how refine the uranium, enrich the concentration spent fuel of uranium-235, manufacture fuel, use it in and high- level waste a reactor, store the spent fuel, and recycle or could be dispose of the waste. People who have jobs isolated 1,000 to in nuclear energy carefully manage each step 3,000 feet in the fuel cycle to protect the public and the beneath the surface environment. of the Earth in a geologic repository.

56 The Harnessed Atom: Nuclear Energy & Electricity Summary

Like all industries, nuclear power plants The United States has not made a final produce wastes. Some of the wastes are decision about how to permanently dispose radioactive and require special methods of of high-level waste. The usable parts disposal. The way we dispose of radioactive of spent fuel can be recycled through a waste depends on process called reprocessing, but the United • How radioactive the waste is States is not currently reprocessing spent • The half-life of the waste fuel. High-level waste requires permanent • The physical and chemical form isolation because it remains radioactive for of the waste thousands of years. Spent fuel and high- level waste left after reprocessing need to be Waste that has been contaminated with isolated deep beneath the Earth’s surface in radioactive material at hospitals, research a geologic repository. labs, industry, and power plants is called low-level waste. Most of the radioactive waste from a nuclear power plant is low- level. Usually it is sealed in steel drums and buried at licensed low-level waste disposal sites.

Nuclear fuel is removed from the reactor when it can no longer support fission efficiently. This spent fuel from power plants can be considered high-level waste. Spent fuel is stored in water in spent fuel pools near the reactor where it cools and undergoes radioactive decay. After a year or two in the spent fuel pool, spent fuel can be removed from the pool and stored in dry casks.

Lesson 7 Waste from Nuclear Power Plants 57

Lesson 8 CONCERNS Introduction Nuclear energy is one of our three largest sources of electricity. It is important for us to make sure nuclear power plants are safe and reliable. In decisions to build and operate a nuclear power plant, safety and security are essential concerns. Learning from past accidents, understanding this energy source, and protecting against risk are important in our energy mix.

TOPICS: Safety at nuclear What concerns do people have jobs in industry. Each year, the injury rate power plants about nuclear power plant safety? is lower in the nuclear power industry than Design features Engineering safety Safety must be the primary concern when other jobs, even office work like finance Barriers and backups we plan, build, and operate a nuclear Regulations and real estate. Security power plant. The main questions people Accidents have about nuclear power plant safety Preventing accidents is the focus when Three Mile Island Chernobyl center around radiation because the fuel people design, build, and operate nuclear Fukushima in a reactor becomes very radioactive. power plants. As a result, nuclear power Learning from accidents Nuclear power plants release very little Informed decisions radiation as they make electricity. However, Risk and benefits Utility costs if an accident released a large amount of Tradeoffs radiation, it would be serious.

Safety includes protecting people who work at the nuclear power plant as well as the people living nearby. It also includes protecting the environment and the power plant itself from damage. Safety is every employee’s responsibility. Working at a

nuclear power plant is one of the safest Nuclear power plants have safety systems that are inspected by workers and regulators.

Lesson 8 Concerns 59 Lesson 8 CONCERNS

plants in the United States have been very reliable and have a record for operating safely. However, the record is not perfect. There have been accidents at nuclear power plants in the past.

Each way that we have of producing

electricity has its own Regulators inspect the way nuclear power plants are operated safety concerns. For and maintained. this reason, each type The Nuclear Regulatory Commission of power plant—coal, nuclear, hydro, – the NRC – must grant a license to gas, solar, wind—has special design the power plant before it can operate. features to protect people and the Then NRC experts conduct regular environment. The safety requirements inspections to make sure the plant runs for nuclear power plants are the safely and that the utility performs strictest. proper maintenance. Each nuclear power plant has an NRC inspector What keeps U.S. nuclear plants assigned to work at the power plant as safe? his or her full time job. Nuclear engineers focus on safety when they design reactor systems. Scientists, Design safety. The physics of a nuclear engineers, architects, and regulators power plant design help keep it safe. all work together as they plan plants. The characteristics of the fuel, the They use the natural properties of the coolant, and the chain reaction itself fuel and fission for a safe design. Then safeguard against accidents. Fuel in a they add engineered safety systems that reactor is concentrated just enough to protect against failure. Around this, they keep the reaction going. It is too diluted build strong barriers to keep radioactive to explode like a bomb. material inside the plant. To make sure

that the plant is run properly, operators As fuel gets hotter, the chain reaction take years of special training and tests. slows down. This property naturally helps limit the rate of fission.

60 The Harnessed Atom: Nuclear Energy & Electricity The water used as a coolant is also necessary for a chain reaction. If cooling water is lost from around the fuel, the chain reaction will stop and the heat from the fuel will drop to 1.5 percent within an hour. Although the remaining heat would damage the reactor, the fission Nuclear power plants are built to withstand hazards like tornadoes. reaction would not keep going. Safety barriers. Utilities build nuclear power plants to withstand all environmental Engineered safety. Every safety-related hazards, including tornadoes, hurricanes, system in a nuclear plant has backup fires, , and . Engineers systems. For example, designers include design for safety in the event of an backup to circulate water in the , even for plants located in areas of reactor if the main pumps should ever moderate or low earthquake activity. quit working. There are also more backup pumps just in case the first backups should The containment building that houses fail. There are also backup cooling systems, the reactor works as a barrier that instruments, and electric power systems. keeps radiation inside, away from the environment. Other barriers also hold in radiation. Uranium fuel is in solid ceramic form that does not rust or dissolve. It can The containment withstand very high temperatures. The building ceramic fuel is sealed inside metal fuel rods around a reactor is that make up the core. A massive steel built from pressure vessel surrounds this reactor core. concrete reinforced All of these barriers keep radiation in the with steel like reactor and out of the environment. the exhibit shown here.

Lesson 8 Concerns 61 Lesson 8 CONCERNS

In late March 2011, scientists at Cook Nuclear Power Plant in Michigan took measurements of the radiation around their site. They recorded a level of 0.05 millirem (mrem). The graphic below shows how this level compares to other naturally occurring and human-made radiation that Americans are exposed to each year.

0.08 MREM 1–2 MREM 10 MREM 30 MREM watching TV chest X-ray cosmic rays (average for most of U.S.)

What regulations apply to U.S. in Lesson 4, everyone receives natural and nuclear power plants? human-made radiation all the time. Regulations require utilities to develop detailed plans to prepare for emergencies. U.S. nuclear power plants add about The utility must immediately notify the 0.0001 millisievert (0.01 millirem) a public, the NRC, and State and local year to the radiation received by people governments if a problem occurs. The living within 50 miles of a nuclear power utility must also have plans for evacuating plant. Most scientists agree that this people who live nearby. Emergency is insignificant when compared to the officials, plant employees, firefighters, 6.2 millisievert (620 millirem) of total rescue teams, and police teams regularly radiation the average American receives practice putting the plans into to be each year. ready to respond to accidents. What about the radioactivity Isn’t even a small amount of from spent fuel? radiation harmful? When reactor operators take fuel out of Some people are concerned about low levels the reactor, it is very radioactive. It must be of radioactivity released by nuclear power handled carefully and shielded to protect plants generating electricity. As you learned workers. Today, spent fuel (used fuel) is stored securely at power plants under water

62 The Harnessed Atom: Nuclear Energy & Electricity in spent fuel pools or in dry casks. This keeps What happened at Three radiation away from workers and people Mile Island? living near the plant. In the future, we will A 1979 accident at the Three Mile Island use permanent disposal to isolate high-level plant in Pennsylvania was the most serious radioactive waste for thousands of years. nuclear power plant accident in the United States. Plant operators mistook readings Can terrorists use nuclear power from the reactor systems and turned off plant fuel to make nuclear automatic safety systems. This caused the bombs? reactor to lose cooling water. The reactor No. The uranium fuel used in nuclear fuel overheated and seriously damaged the power plants will not work for a nuclear core. High levels of radiation were released bomb. It is not enriched enough to explode into the containment building, and the heat as a weapon. Some people worry that ruined the reactor unit. terrorists might try to steal or hijack a fuel shipment to try to make a “dirty bomb” by The protective barriers at the plant using explosives to spread contamination kept most radiation inside, but traces of in the environment. Although this would radioactive iodine and xenon gas were scare people, it would not be very effective. released off the plant site. The average However, nuclear fuel is kept under strict radiation exposure to people living in that security to prevent anyone from getting area was about 0.01 millisievert (1 millirem) access to it. from the accident. This is less than the radiation from a chest x-ray, which is about How do nuclear power plants 0.06 millisievert (6 millirem). It’s also far affect other kinds of security? less than the natural background radiation So far, we have talked about physical safety. in that part of Pennsylvania, which is about Another kind of security involves protecting 1 to 1.25 millisievert (100 to 125 millirem) our economy. The United States depends on per year. There were no serious injuries. energy for every part of our economy. When However, it took weeks before authorities energy is not available, or the price goes up fully understood what had happened and quickly, it affects every person. We import people living near the plant were concerned much of our energy from other countries. that it could be dangerous. It was costly for Using nuclear energy to make electricity the utility to clean up the damaged reactor is one way our nation maintains a reliable and to replace the electricity it produced. electricity supply at a reasonable price.

Lesson 8 Concerns 63 Lesson 8 CONCERNS

What about accidents in other tsunami, or tidal wave that flooded the countries? What happened at coast and killed about 19,000 people and Chernobyl? injured 28,000 more. The Fukushima In April 1986, there was a very serious Dai-Ichi nuclear is on the accident at a reactor in Chernobyl, coast. The plant has six reactors, but three , in the former . were shut down for regular maintenance. Operators were performing unauthorized When the earthquake occurred, the three tests that caused a steam explosion and operating reactors automatically shut down fire that destroyed the reactor. Two and emergency cooling systems came on. workers died in the accident. Another 28 However, the earthquake cut off the supply workers died several months later. of electricity to the plant, so emergency backup generators started to supply The Chernobyl reactors were an entirely electricity. Then the tsunami flooded over different design than power plants in the emergency backup generators. Without the United States. Chernobyl reactors electricity, plant operators were not able to did not have containment buildings like keep the reactor and spent fuel cooled. the ones required for U.S. power plants. Damage to the nuclear fuel caused The Chernobyl accident released a large explosions of hydrogen gas. There amount of radioactive contamination were releases of radiation. People were to areas of Belarus, Ukraine, and other evacuated from areas around the plant. countries in Europe. Some food and water supplies were contaminated, and workers were exposed Studies by a United Nations scientific to radiation. No one died because of committee indicate that there were more the damage to the power plant, but one than the normal number of cases of worker died in the tsunami. cancer in children near the site. No other increase in cancer or other diseases has What do these accidents mean been found in 25 years since the accident. for reactor safety? However, it is possible that we could see Whenever there is an accident or problem some increase in diseases linked to radiation at a nuclear power plant, experts in the from Chernobyl in the future. United States and around the world study it to see what we can learn to make our What happened at Fukushima in nuclear plants safer. For example, after Japan? Three Mile Island, all reactors in the United In March 2011, there was a massive States had to meet new safety regulations, earthquake off the coast of Japan. The and the operators had more training. After earthquake caused a 14 meter (49 foot)

64 The Harnessed Atom: Nuclear Energy & Electricity In deciding how to make our electricity, calculations and analysis. we will have to For example, to study risk in weigh the risks and benefits the nuclear power industry, of using scientists examine every various energy sources. step, beginning with mining fuel, building and operating power plants, and ending with decommissioning the power plants and disposing of nuclear wastes.

Risk assessment helps us understand the risks the earthquake in Japan, the U.S. Nuclear involved by comparing them to other Regulatory Commission analyzed reactors situations. It also helps pinpoint ways to to make sure they could withstand similar make things safer. natural . The lessons learned led to How do people make decisions changes in the safety systems to protect the about risks? reactor fuel in case power is cut off at a plant. Scientists who study human behavior tell us that people are more likely to distrust How do these concerns affect new or unfamiliar things. When electricity, U.S. energy decision making? trains, and automobiles were first developed, There are good aspects and problems with some people were too frightened to use every energy source. The good aspects are them. In more recent times, the same was called benefits. The problems are called true with ovens and cell phones. risks. Most people feel that the benefits of a reliable energy supply outweigh certain When given choices, we are most likely to risks. The question is really about how we pick things that are familiar. For example, can better understand and protect against some people refuse to fly in airplanes but risks when using energy resources like will travel in cars, even though statistics nuclear power. show that airplanes are less likely to have accidents. Medical vaccinations, prescription There is an area of science called risk drugs, food preservatives, and cell phones assessment that has been used to study the are other examples of new technologies that risks in various industries. Risk assessment have changed the way we live, but that also can involve detailed mathematical concern some people.

Lesson 8 Concerns 65 Lesson 8 CONCERNS

We have grown accustomed to certain hazards even though they are comparatively dangerous. You accept certain risks when you bicycle or skateboard, go sledding or swimming, or participate in sports like football, basketball, soccer, or softball. All of our activities involve risk.

What are the risks and benefits of nuclear energy? As with all energy sources, nuclear energy has both risks and benefits. Major questions we must consider about the risks and benefits of our energy options are Many of our favorite activities involve risk. 1. What are the risks of using an energy source to generate electricity? 2. Do the benefits outweigh the risks? 3. What are the risks of not having affordable electricity and the quality of life that goes with it?

These are very difficult questions and there are no simple answers. But these are questions you and other Americans are going to be answering in the future.

66 The Harnessed Atom: Nuclear Energy & Electricity Summary

In decisions to design, build, license, and is not perfect. There have been accidents operate nuclear power plants, safety is at nuclear power plants. The most serious the primary concern. Engineers design ones did not happen in the United States. a series of barriers to provide layers of When there is a problem at a power plant containment to keep radiation from being anywhere in the world, experts study what released during regular operations of a happened to find ways to make plants safer. nuclear plant or during an emergency. They design nuclear power plants to One issue in the United States today withstand natural disasters, including fire, is how to meet our future electricity floods, tornadoes, earthquakes, tsunamis, demands. All choices involve some risk. and hurricanes. In order to make decisions about this issue, it is important to understand risks The security of nuclear power plants is and benefits. Risk assessment is an area of also part of safety. To ensure safety and science that studies and measures risk to security, workers at nuclear power plants help us make decisions. spend many hours planning, training, and practicing for emergencies. Being informed about nuclear energy involves defining the concerns people have, Nuclear power plants in the United States gathering the facts, and evaluating the have been very reliable and have a record information. for operating safely. However, the record

Lesson 8 Concerns 67

Lesson 9 ENERGY AND YOU Introduction The United States depends on a plentiful supply of energy that is available at affordable prices. Why does that matter to you? Energy costs affect your family, your community, and the businesses around you all the time. When you enter the job market, your fresh ideas on clean energy sources, fuel efficiency, and new technologies can keep America the leader in energy innovation and production.

TOPICS: _Supply and Do energy decisions affect you? If demand is greater than supply, demand Yes. Rising energy prices affect everyone – something will change Energy • Sellers may charge more for their decisions workers, farmers, truck drivers, and Energy and the restaurant owners. If businesses have to product economy • Buyers may be willing to pay more Utilities spend more for energy, they may earn less Energy and you • Buyers may choose to go without profit. Families feel the pinch when they Your future career • Buyers may choose to buy something else options pay their energy bills. That’s why the United States is working to secure our energy supply and meet our demand for energy.

What is supply and demand? Supply is how much of something is available. Demand is how much of it people want. Supply and demand determine the value of things. For example, the supply of oil on the world market determines the price of gasoline. When supply and demand are in Imagine you and your friends have a bag balance, we say they are stable. Prices don’t of gummy bears. The bears are the supply. What if everyone likes the ones best? change much. Red bears are in demand. When you divide the bears, what do you think will happen?

Lesson 9 Energy and You 69 Lesson 9 ENERGY AND YOU

What do supply and demand have sources we have available. This is called to do with energy? our energy mix. Then we must make Energy costs are determined by supply and choices that will provide clean energy at a demand. When energy demand is greater reasonable cost. than supply, prices go up. We also know that energy markets are global. This Current energy research focuses on means that what happens in any part of expanding cleaner sources of electricity, the world affects everyone. including wind and solar, biomass, nuclear energy, clean coal, and natural Energy is not like most other things we gas. The United States is working toward buy. With energy, it is hard for buyers to making 80 percent of our electricity from simply go without or to choose to buy clean energy sources by 2035. Keeping something else. America on the cutting edge of clean sparks new jobs, new How do utilities balance supply industry, and innovations that keep us and demand? safe, healthy, and protect our economy. Utilities build power plants to meet our demand for electricity. However, the For the future, engineers are working on a demand for electricity changes from year new generation of smaller, safer, and more to year. Before deciding to build a power plant, utilities consider supply and demand. Because it takes years to build a new power plant, utilities hire people to plan for what their customers will need in future. In planning, they figure the cost of building power plants, including the cost of borrowing money. They estimate the cost of operating the power plant Energy over its entire lifetime. They also base Demand Energy their choice on the cost of the fuel and Supply whether they can get a steady supply.

How can we plan for energy demand in the future?

To meet tomorrow’s energy demand, Utilities must plan ahead to meet the future demand we must look carefully at the energy for electricity by constructing power plants that help keep supply in balance. Clean energy sources will need to meet most of our demand by 2035.

70 The Harnessed Atom: Nuclear Energy & Electricity No matter what kind of job you want to do when you graduate, you need a strong foundation in computers and math. To take advantage of the career opportunities in your future, you will need to understand how science works and have the skills to use technology for learning more.

Skills that you learn in your science and math classes connect to your life outside school. They will also matter for jobs. What are some jobs in nuclear science? efficient nuclear reactors. Nuclear scientists Your nuclear science career and engineers from around the world are could focus on electricity production, also working together to design a way to nuclear fuel design, medical research, generate electricity using . environmental protection, or even archaeology. Throughout the world, A global race is underway to develop nuclear science is used in industry, cleaner energy technology. Other medicine, agriculture, and environmental countries are playing to win, too. To rise research to provide energy, help save to this challenge, we need to tap into the lives, boost productivity, increase food greatest resource output, and protect we have – your resources. After graduating from high ingenuity. school, you have options that You have many can lead to careers in nuclear science... options within those Why should I fields. Choosing your think about this • 2-year college degree (called an associate’s degree) career starts with now? your interests, skills, • Trade school certificate Tomorrow’s energy and talents. careers will require a • Apprenticeship deep understanding • 4-year college degree (called a bachelor’s degree) of science, and technology. • Graduate school (called a master’s or doctoral degrees)

Lesson 9 Energy and You 71 Lesson 9 ENERGY AND YOU

CareerSnapshot: What are some other nuclear science jobs? As the world’s population grows, the need for food is increasing rapidly. Scientists use radiation to develop crops that produce higher yields, eliminate pests without chemicals, and improve food safety. For example, most pasta consumed today is made from a wheat variety developed by Brent - using this research. In Africa, radiation I work with Advanced Reactor Systems and Safety on nuclear policy and safeguards to helped control the that transmits prevent spread of hazardous materials. My next deadly disease to cattle and people. assignment will be helping design systems for the next generation of smaller, safer, and more efficient reactors. Career choices in environmental research Education: I have a bachelor’s degree in mechanical engineering and a master’s degree and include in nuclear engineering, and am now finishing a • Gamma facility operators, who use doctorate. radiation to destroy like salmonella or E. coli. What are some energy jobs that • Biologists, who conduct experiments use nuclear science? to develop new varieties of crops Electricity demand is growing around the world. Nuclear energy is a clean energy resource that supplies electrical demand CareerSnapshot: without releasing carbon dioxide into the atmosphere. Nuclear energy also powers satellites, ships, and space laboratories. Career choices in nuclear energy include • Reactor operators, who run the systems at a power plant to produce electricity • Engineers, who design power plants and supervise operations • Mathematicians and statisticians, who calculate energy costs and future Jenna - Nuclear Scientist demand I am a food scientist with a specialization in • Nuclear scientists, who explore ways to nuclear science. I use radiation techniques to improve safety and efficiency produce higher yield crops and protect livestock from disease. I also look for ways to eliminate • Technologists, who locate natural pests without the use of traditional chemicals. resources underground Education: I have a bachelor’s degree in nuclear science and bachelor’s degree in .

72 The Harnessed Atom: Nuclear Energy & Electricity • Agricultural technicians, who use radiation to destroy disease-causing CareerSnapshot: germs in food and spices • Research assistants, who help scientists and food engineers collect and analyze data • Technologists, who study natural resources to help make the most of limited water supplies

What are some nuclear medical science jobs? Discoveries in nuclear science have Anthony - Nuclear Physicist dramatically improved people’s health. I do research at a national laboratory on energy and matter. My team is looking at the structure of benefits over 40,000 matter and ways to use energy within the atom’s patients daily. Doctors rely on x-rays to nucleus. Education: I have a master’s degree in physics, diagnose broken bones or find tumors which took another 2 years after my bachelor’s without surgery. They use radiation to treat degree. Most jobs in my field require at least a B.S. in physics or a related area, as well as strong and other types of cancer. More math and writing skills. than half of all medical equipment used

CareerSnapshot: in hospitals is sterilized with radiation. Scientists use radioisotopes to develop more than 80 percent of all new drugs. Career choices in nuclear medicine and biology include • Health physicists, who assure that people who work with radiation do it safely • Physicians, who use nuclear medicine to diagnose and treat diseases Madison - Radiological Technologist • Nuclear medicine technologists, who I assist doctors with x-rays and imaging scans that run tests in hospitals help diagnose tumors, certain types of cancer, and other diseases. • X-ray technicians, who work with Education: After high school, I took two years of patients in hospitals college courses that led to an associate’s degree. My coursework included anatomy, pathology, patient care, radiation physics and protection, and image evaluation.

Lesson 9 Energy and You 73 Lesson 9 ENERGY AND YOU


SCIENCE TECHNOLOGY ENGINEERING MATHEMATICS Science exercises Technology skills Engineering uses Math skills give the mind and increase your ability science and math, you the ability teaches logical to use, understand, and applies them to identify and thinking. It and change many to design, create, analyze patterns encourages of the tools you or modify nearly and use logic. It looking at things already use, like any structure, develops critical in different ways. computers or your machine, or thinking skills and cell phone, and to material. problem-solving help develop new skills. ones.

I like to I like to I am logical, I’m good work with help precise, and with my hands. people. creative. numbers.

maybe you would be interested in becoming a...

Power Plant , Nuclear Medicine Nuclear Engineer who Applied Mathematician Distributor, or Dispatcher Technologist who uses could help find industrial or who creates models to solve who controls the systems scanners to create images medical uses for nuclear practical problems in fields that generate and distribute of areas of a patient’s body. energy and radiation. You like business, government, electric power. Nuclear They prepare radioactive engineering, and the could also design nuclear sciences. You could work power reactor operators drugs and administer them power plants. Some nuclear regularly check power plant to patients undergoing with a team of engineers and engineers work for NASA, scientists and solve real- equipment to ensure it is scans. Radioactive drugs testing space shuttles to working properly. cause abnormal areas of the world energy ensure safety in and on problems. body to appear launch. Requires different from normal areas in the images. Requires High school diploma, Requires 6- or 4-year college degree technical skills, continuous Requires 4-year college degree on-the-job training. College or Navy career is desirable. 2-year college degree Demand Demand Demand Demand 3,100 jobs in 2010 with 19,100 jobs in 2010 with 16% expected increase in 10% expected increase in positions through 2020 55,900 jobs in 2010 21,900 jobs in 2010 with positions through 2020 expected to be steady 19% expected increase in through 2020 positions through 2020

74 The Harnessed Atom: Nuclear Energy & Electricity What are other careers in nuclear science? Lots of other careers use nuclear science. Archaeologists and paleontologists use nuclear techniques to determine the age of objects. Crime investigators test evidence using analysis. Art experts use nuclear tools like x rays to study paintings to see if they are valuable original art or fakes.

Why does energy science matter to you? You will be making choices about how we should supply Today’s students will be tomorrow’s energy decision makers, our future energy demands. designers, and workers. Learning about the world’s energy resources and the science behind how they can be used, will make you a better decision-maker in the future.

Meeting the world’s energy demands will take many solutions. A mix of energy supplies is what Americans use now. That mix will change as supply and demand change. Planning for the best future energy mix will require smart scientists, engineers, and inventors working to create new energy options and to conserve what we have. Perhaps you will be one of these people.

Lesson 9 Energy and You 75 Lesson 9 ENERGY AND YOU


Supply and demand determine the cost of You and your classmates will be making all things, including electricity. decisions about how we should meet our future energy demands. Planning the best The question we need to answer is how mix of energy for the future will require America will supply our demand for smart scientists, engineers, inventors, and electricity. In deciding what type of power citizens. What will you be? plant to build, utilities must consider construction, fuel, and operating costs. The sum of these costs will help them decide how to make electricity in the future.

76 The Harnessed Atom: Nuclear Energy & Electricity Credits

Cover Lesson 4 Lesson 7 Cover Leidos Pg 27 Photos.com Pg 51 NRC Pg 28-30 Leidos Pg 51 Site Restoration Content Standards, Grades 5-8, National Pg 31 Thinkstock Limited, , Science Education Standards, 1996; Reprinted Pg 32-34 Leidos Pg 51 Thinkstock with permission from the National Academy of Pg 35 Thinkstock Pg 52 NRC Sciences, Courtesy of the National Academies Pg 35 Photos.com Pg 53 Leidos Press, Washington, D.C. Pg 36 Thinkstock Pg 54 NRC Pg 55 Thinkstock Lesson 1 L4 11 Leidos Pg 55 NRC Pg 1 Photos.com L4 13 Leidos Pg 56 Leidos Pg 2 Thinkstock L4 17 Leidos Pg 57 Thinkstock Pg 2 Leidos L4 20, 22 Leidos L7 18-22 Leidos Pg 3 Leidos L4 23, 25 Thinkstock Pg 3 Thinkstock Lesson 5 Lesson 8 Pg 4 Leidos Pg 37 Photos.com Pg 59 Thinkstock Pg 6-8 Photos.com Pg 37 Leidos Pg 59 NRC Pg 9 Leidos Pg 38 USGS and the Mineral Pg 60 NRC Pg 9 Thinkstock Information Institute Pg 61 NOAA Pg 10 Thinkstock Pg 39 EIA Pg 61 Entergy Nuclear Pg 11 Leidos Pg 40 USEC, Inc. Pg 62 Thinkstock Pg 11 Thinkstock Pg 40 Leidos Pg 65-67 Thinkstock Pg 12 Thinkstock Pg 41 Leidos L8 8 Leidos L1 6 - 9 Thinkstock Pg 41 NRC L8 9 Thinkstock L1 10 Leidos Pg 41 NASA L8 11 Leidos L1 11 DOE and EPA Pg 42 Thinkstock Lesson 9 L5 9-10 Leidos Lesson 2 Pg 69 Thinkstock L5 11, 13 Thinkstock Pg 13 Photos.com Pg 69 Photos.com L5 11-14 Leidos Pg 13 Leidos Pg 70-73 Thinkstock L5 16-17 Leidos Pg 14-16 Leidos Pg 74 Leidos Pg 17-18 Thinkstock Lesson 6 Pg 75-76 Thinkstock L2 9 Thinkstock Pg 43 Photos.com L9 11 Thinkstock L2 12-16 Leidos Pg 43-44 Leidos L9 13 Leidos L2 17-19 Jonathan Hare Pg 44 NRC www.creative-science.org.uk Pg 45 Photos.com Lesson 10 L2 20, 22 Leidos Pg 45 SNPTC, Westinghouse Pg 77 Leidos L2 24-26 Leidos Pg. 46 NRC Pg 81 -87 Leidos Lesson 3 Pg 46 Photos.com Pg 46 Leidos Pg 19 Photos.com Pg 47 Leidos Pg 19 Jon Reis Photography Pg 47 Photos.com Pg 20 Photos.com Pg 47 NRC Pg 21 Leidos Pg 48 Thinkstock Pg 21 University of Tennessee Pg 48 Leidos Pg 22 Leidos Pg 23 Thinkstock Pg 49 Thinkstock Pg 23 Photos.com L6 6-23 Leidos Pg 24 NASA Pg 25 Thinkstock L3 5, 7 Leidos L3 12-15 Leidos November 2013