Nuclear ChemistryNuclear Chemistry

Chapter 25Chapter 25

Characteristics of Chemical & Characteristics of Chemical & Nuclear ReactionsNuclear Reactions

Chemical ReactionsChemical Reactions1.1. Occur when bonds are Occur when bonds are

broken and formedbroken and formed2.2. Atoms remain Atoms remain

unchanged, though unchanged, though they may be they may be rearrangedrearranged

3.3. Involve only valence Involve only valence electronselectrons

4.4. Associated with small Associated with small energy changesenergy changes

5.5. Reaction rate is Reaction rate is influenced by influenced by temperature, pressure, temperature, pressure, concentration, and concentration, and catalystscatalysts

Nuclear ReactionsNuclear Reactions1.1. Occur when nuclei emit Occur when nuclei emit

particles and/or raysparticles and/or rays2.2. Atoms are often Atoms are often

converted into atoms converted into atoms of another elementof another element

3.3. May involve protons, May involve protons, neutrons, and low-orbit neutrons, and low-orbit electronselectrons

4.4. Associated with large Associated with large energy changesenergy changes

5.5. Reaction rate is not Reaction rate is not normally affected by normally affected by temperature, pressure, temperature, pressure, or catalystsor catalysts

Balancing Nuclear EquationsBalancing Nuclear Equations

Rubidium undergoes electron Rubidium undergoes electron capture to form krypton. Show the capture to form krypton. Show the balanced equation.balanced equation.

Reactant: Reactant: 8181Rb + Rb + 00

ee

3737

-1-1

Product: Product: 8181Kr + Kr + 00x-rayx-ray

3636 0 0

Balancing Nuclear EquationsBalancing Nuclear Equations

Oxygen-15 undergoes positron Oxygen-15 undergoes positron emission. Show the balanced emission. Show the balanced equation.equation.

Reactant: Reactant: 1515O O

88

Product: Product: 1515N + N + 00

77

11

Balancing Nuclear EquationsBalancing Nuclear Equations

Thorium-231 becomes Protactinium-Thorium-231 becomes Protactinium-231. Show the balanced equation and 231. Show the balanced equation and identify the type of radioactive decay.identify the type of radioactive decay.

Reactant: Reactant: 231231ThTh

9090

Product: Product: 231231Pa + Pa + 00

9191 -1 -1

UraniumUranium Uranium is a naturally radioactive element that can be Uranium is a naturally radioactive element that can be

found in the crust of the Earth.found in the crust of the Earth. This element, quite abundant in many areas of the world, is This element, quite abundant in many areas of the world, is

naturally radioactive. naturally radioactive. Certain isotopes of uranium can be used as fuel in a nuclear Certain isotopes of uranium can be used as fuel in a nuclear

power plant.power plant. The uranium is formed into ceramic pellets about the size of The uranium is formed into ceramic pellets about the size of

the end of your finger. the end of your finger. By bombarding uranium with neutrons, neptunium can be By bombarding uranium with neutrons, neptunium can be

synthesized, which decays into plutonium:synthesized, which decays into plutonium:238238U + U + 11n n 239239U U 239239Np + Np + 00 9292 0 0

9292 93 93 -1 -1

239239Np Np 239239Pu + Pu + 00

93 93 94 94 -1 -1

Conservation of MassConservation of Mass Matter is neither created nor destroyed.Matter is neither created nor destroyed. This is true, with the caveat that matter can be This is true, with the caveat that matter can be

converted into energy (and vice versa) according converted into energy (and vice versa) according to the equation:to the equation:– E= E= mcmc22

– E= change in energy,E= change in energy,– m=change in mass,m=change in mass,– c=speed of light (3.00x10c=speed of light (3.00x1088 m/s) m/s)

Thus, ANY reaction that has a consumes or Thus, ANY reaction that has a consumes or produces energy will also consume or produce an produces energy will also consume or produce an accompanying quantity of mass.accompanying quantity of mass.

Thus, the total conversion of 1kg of matter yields Thus, the total conversion of 1kg of matter yields an equivalent of 1 x (3x108)2 = 9x 10an equivalent of 1 x (3x108)2 = 9x 101616 joules - joules - this is approximately the energy output of a 200 this is approximately the energy output of a 200 MW power station running for 14 years! MW power station running for 14 years!

Binding Energy & The Mass Binding Energy & The Mass DefectDefect

Recall: for nuclei to be Recall: for nuclei to be stablestable there must exist a there must exist a strong nuclear strong nuclear forceforce between the nucleons that is short range, attractive, and between the nucleons that is short range, attractive, and can overcome the coulomb repulsion of the protons. can overcome the coulomb repulsion of the protons. – Now suppose we assemble a nucleus of Now suppose we assemble a nucleus of NN neutrons and neutrons and ZZ protons. protons. – There will be an There will be an increaseincrease in the electric potential energy due to the in the electric potential energy due to the

electrostatic forces between the protons trying to push the nucleus electrostatic forces between the protons trying to push the nucleus apart apart

– but there is a but there is a greatergreater decrease of potential energy due to the decrease of potential energy due to the strong nuclear force acting between the nucleons and attracting strong nuclear force acting between the nucleons and attracting them to one another.      them to one another.     

As a consequence, the nucleus has an overall net As a consequence, the nucleus has an overall net decreasedecrease in in its potential energy.its potential energy.

This decrease in potential energy is called the This decrease in potential energy is called the nuclear binding nuclear binding energyenergy

The decrease per nucleon is called the The decrease per nucleon is called the binding energy per binding energy per nucleonnucleon. .

The loss of this energy is, by the mass-energy relation, The loss of this energy is, by the mass-energy relation, equivalent to a loss of mass called the mass defect. equivalent to a loss of mass called the mass defect.

The variation of binding energy The variation of binding energy per nucleon with atomic mass per nucleon with atomic mass

number number

So how is energy released in stars? This can be explained by a So how is energy released in stars? This can be explained by a graph graph of the binding energy per nucleon against atomic mass of the binding energy per nucleon against atomic mass number Anumber A

Releasing Nuclear EnergyReleasing Nuclear Energy

The curve reaches a maximum at iron, The curve reaches a maximum at iron, which, because of its high binding energy which, because of its high binding energy per nucleon, indicates that the protons per nucleon, indicates that the protons and neutrons are very tightly bound and and neutrons are very tightly bound and iron is a very stable nucleus. iron is a very stable nucleus.

Beyond iron, the binding energy per Beyond iron, the binding energy per nucleon falls slightly as nucleon falls slightly as AA increases increases towards the more massive nuclei. towards the more massive nuclei.

Two processes can release energy from Two processes can release energy from the nucleus of an atom. They are the nucleus of an atom. They are nuclear nuclear fissionfission and and nuclear fusionnuclear fusion..

Nuclear FissionNuclear Fission

In In nuclear fissionnuclear fission a massive nucleus such a massive nucleus such as uranium splits in two to form two lighter as uranium splits in two to form two lighter nuclei of approximately equal mass. nuclei of approximately equal mass.

This happens on the This happens on the fallingfalling part of the part of the curve so that mass is lost and binding curve so that mass is lost and binding energy released when very heavy energy released when very heavy elements fission to nuclei of elements fission to nuclei of smallersmaller mass mass number. Nuclear fission is responsible for number. Nuclear fission is responsible for the release of energy in nuclear reactors the release of energy in nuclear reactors and atomic bombs.and atomic bombs.

Fission Inside Nuclear Fission Inside Nuclear ReactorsReactors

235235U + U + 11n n 236236

U U 9292Kr + Kr + 11nn141141Ba + Ba + 11nn

9292 0 0 9292 3636 0 0 56 56 0 0

Each fission of Uranium-235 releases Each fission of Uranium-235 releases additional nuetrons. If 1 fission reaction additional nuetrons. If 1 fission reaction produces 2 neutrons, these 2 neutrons can produces 2 neutrons, these 2 neutrons can create 2 additional fission reactions each.create 2 additional fission reactions each.– This is a self-sustaining process called a chain This is a self-sustaining process called a chain

reaction!reaction!– Both the # of fissions and amt of energy Both the # of fissions and amt of energy

release increase extremely rapidly.release increase extremely rapidly.– The explosion from an atomic bomb represents The explosion from an atomic bomb represents

the results of an uncontrolled chain reaction.the results of an uncontrolled chain reaction.

Critical MassCritical Mass It isn’t enough just to have a sample of It isn’t enough just to have a sample of

fissionable material, like uranium-235.fissionable material, like uranium-235. You must also have a critical mass of your You must also have a critical mass of your

material.material.– If there is not a sufficient amount of mass, the released If there is not a sufficient amount of mass, the released

neutrons will dissipate before finding another unstable neutrons will dissipate before finding another unstable nucleus with which to react.nucleus with which to react.

– No chain reaction will form and the reaction will be No chain reaction will form and the reaction will be unsustainable.unsustainable.

The amount of mass necessary to sustain a chain The amount of mass necessary to sustain a chain reaction is called the critical mass.reaction is called the critical mass.– Below this amount is called the subcritical mass.Below this amount is called the subcritical mass.– Above this amount is called the supercritical mass.Above this amount is called the supercritical mass.

Supercritical masses cause rapid acceleration of the Supercritical masses cause rapid acceleration of the reaction and can lead to a violent explosion.reaction and can lead to a violent explosion.

Pressurized Water ReactorPressurized Water Reactor

Components of a Nuclear Components of a Nuclear ReactorReactor

Fuel Elements: Usually pellets of uranium oxide (UOFuel Elements: Usually pellets of uranium oxide (UO22) ) arranged in corrosion-resistant tubes to form fuel arranged in corrosion-resistant tubes to form fuel rods. The rods, enriched with 3% uranium-235, are rods. The rods, enriched with 3% uranium-235, are arranged into fuel assemblies in the reactor core. arranged into fuel assemblies in the reactor core.

Control Rod: cadmium, hafnium, or boron rods Control Rod: cadmium, hafnium, or boron rods absorb excess neutrons, controlling the reaction absorb excess neutrons, controlling the reaction within the reactor. (Secondary shutdown systems within the reactor. (Secondary shutdown systems involve adding other neutron absorbers, usually as a involve adding other neutron absorbers, usually as a fluid, to the system.)fluid, to the system.)– If the reaction isn’t properly controlled, disaster resultsIf the reaction isn’t properly controlled, disaster results– Cf. Three Mile Island (U.S. 1979), Chernobyl (Ukraine, 1986)Cf. Three Mile Island (U.S. 1979), Chernobyl (Ukraine, 1986)

Moderator: This is material which slows down the Moderator: This is material which slows down the neutrons released from fission so that they cause neutrons released from fission so that they cause more fission. It may be water, heavy water more fission. It may be water, heavy water (deuterated), or graphite (carbon). (deuterated), or graphite (carbon).

Coolant: fluid circulating in the reactor core, serving Coolant: fluid circulating in the reactor core, serving to lower the reaction temperature; usually waterto lower the reaction temperature; usually water

Producing Electricity from Producing Electricity from Nuclear ReactorsNuclear Reactors

In America today, nuclear energy plants are the In America today, nuclear energy plants are the second largest source of electricity after coal -- second largest source of electricity after coal -- producing approximately 21% of our electricity.producing approximately 21% of our electricity.

With the exception of solar, wind, and With the exception of solar, wind, and hydroelectric plants, all others including hydroelectric plants, all others including nuclear plants:nuclear plants:– Convert water to steam Convert water to steam – The steam spins the propeller-like blades of a The steam spins the propeller-like blades of a

turbineturbine– The turbine blades spin the shaft of a generator.The turbine blades spin the shaft of a generator.– Inside the generator, coils of wire and magnetic Inside the generator, coils of wire and magnetic

fields interact to create electricityfields interact to create electricity

Turbine & GeneratorTurbine & Generator

Converting Water to SteamConverting Water to Steam

The energy needed to boil water into The energy needed to boil water into steam is produced in one of two ways: steam is produced in one of two ways: – by burning coal, oil, or gas (fossil fuels) in a by burning coal, oil, or gas (fossil fuels) in a

furnacefurnace– by splitting certain atoms of uranium in a by splitting certain atoms of uranium in a

nuclear energy plant. nuclear energy plant. Nothing is burned or exploded in a nuclear Nothing is burned or exploded in a nuclear

energy plant. energy plant. Rather, the uranium fuel generates heat Rather, the uranium fuel generates heat

through fission. through fission.

Fast Breeder ReactorsFast Breeder Reactors Under appropriate operating conditions, the Under appropriate operating conditions, the

neutrons given off by fission reactions can "breed" neutrons given off by fission reactions can "breed" more fuel from otherwise non-fissionable isotopes. more fuel from otherwise non-fissionable isotopes.

The most common breeding reaction is that of The most common breeding reaction is that of plutonium-239 from non-fissionable uranium-238. plutonium-239 from non-fissionable uranium-238.

The term "fast breeder" refers to the types of The term "fast breeder" refers to the types of configurations which can actually produce more configurations which can actually produce more fissionable fuel than they use, such as the LMFBR. fissionable fuel than they use, such as the LMFBR.

This scenario is possible because the non-This scenario is possible because the non-fissionable uranium-238 is 140 times more fissionable uranium-238 is 140 times more abundant than the fissionable U-235 and can be abundant than the fissionable U-235 and can be efficiently converted into Pu-239 by the neutrons efficiently converted into Pu-239 by the neutrons from a fission chain reaction. from a fission chain reaction.

France has made the largest implementation of France has made the largest implementation of breeder reactors with its large Super-Phenix reactor breeder reactors with its large Super-Phenix reactor and an intermediate scale reactor (BN-600) on the and an intermediate scale reactor (BN-600) on the Caspian Sea for electric power and desalinization. Caspian Sea for electric power and desalinization.

Breeding Plutonium-239Breeding Plutonium-239

Fissionable plutonium-239 can Fissionable plutonium-239 can be produced from non-be produced from non-fissionable uranium-238 by fissionable uranium-238 by the reaction illustrated. the reaction illustrated.

The bombardment of uranium-The bombardment of uranium-238 with neutrons triggers two 238 with neutrons triggers two successive beta decays with successive beta decays with the production of plutonium. the production of plutonium. The amount of plutonium The amount of plutonium produced depends on the produced depends on the breeding ratio. breeding ratio.

Plutonium Breeding Plutonium Breeding RatioRatio

In the breeding of plutonium fuel in breeder reactors, an In the breeding of plutonium fuel in breeder reactors, an important concept is the breeding ratio, the amount of important concept is the breeding ratio, the amount of fissile plutonium-239 produced compared to the amount of fissile plutonium-239 produced compared to the amount of fissionable fuel (like U-235) used to produced it. fissionable fuel (like U-235) used to produced it.

In the liquid-metal, fast-breeder reactor (LMFBR), the target In the liquid-metal, fast-breeder reactor (LMFBR), the target breeding ratio is 1.4 but the results achieved have been breeding ratio is 1.4 but the results achieved have been about 1.2 . This is based on 2.4 neutrons produced per U-about 1.2 . This is based on 2.4 neutrons produced per U-235 fission, with one neutron used to sustain the reaction.235 fission, with one neutron used to sustain the reaction.

The time required for a breeder reactor to produce enough The time required for a breeder reactor to produce enough material to fuel a second reactor is called its doubling time, material to fuel a second reactor is called its doubling time, and present design plans target about ten years as a and present design plans target about ten years as a doubling time. doubling time.

A reactor could use the heat of the reaction to produce A reactor could use the heat of the reaction to produce energy for 10 years, and at the end of that time have energy for 10 years, and at the end of that time have enough fuel to fuel another reactor for 10 years. enough fuel to fuel another reactor for 10 years.

Liquid-Metal, Fast-Breeder Liquid-Metal, Fast-Breeder ReactorReactor

The plutonium-239 breeder reactor is commonly called a fast The plutonium-239 breeder reactor is commonly called a fast breeder reactor, and the cooling and heat transfer is done by a breeder reactor, and the cooling and heat transfer is done by a liquid metal. liquid metal. – The metals which can accomplish this are sodium and lithium, with The metals which can accomplish this are sodium and lithium, with

sodium being the most abundant and most commonly used.sodium being the most abundant and most commonly used. The construction of the fast breeder requires a higher enrichment The construction of the fast breeder requires a higher enrichment

of U-235 than a light-water reactor, typically 15 to 30%. of U-235 than a light-water reactor, typically 15 to 30%. The reactor fuel is surrounded by a "blanket" of non-fissionable U-The reactor fuel is surrounded by a "blanket" of non-fissionable U-

238. 238. No moderator is used in the breeder reactor since fast neutrons No moderator is used in the breeder reactor since fast neutrons

are more efficient in transmuting U-238 to Pu-239. are more efficient in transmuting U-238 to Pu-239. At this concentration of U-235, the cross-section for fission with At this concentration of U-235, the cross-section for fission with

fast neutrons is sufficient to sustain the chain-reaction. fast neutrons is sufficient to sustain the chain-reaction. Using water as coolant would slow down the neutrons, but the use Using water as coolant would slow down the neutrons, but the use

of liquid sodium avoids that moderation and provides a very of liquid sodium avoids that moderation and provides a very efficient heat transfer medium. efficient heat transfer medium.

LMFB Reactor DiagramLMFB Reactor Diagram

Liquid Sodium CoolantLiquid Sodium Coolant

Liquid sodium is used as the coolant and heat-transfer medium Liquid sodium is used as the coolant and heat-transfer medium in the LMFBR reactor. in the LMFBR reactor. – That immediately raised the question of safety since sodium metal That immediately raised the question of safety since sodium metal

is an extremely reactive chemical and burns on contact with air or is an extremely reactive chemical and burns on contact with air or water (sometimes explosively on contact with water). water (sometimes explosively on contact with water).

– It is true that the liquid sodium must be protected from contact with It is true that the liquid sodium must be protected from contact with air or water at all times, kept in a sealed system. air or water at all times, kept in a sealed system.

– However, it has been found that the safety issues are not However, it has been found that the safety issues are not significantly greater than those with high-pressure water and steam significantly greater than those with high-pressure water and steam in the light-water reactors.in the light-water reactors.

Sodium is a solid at room temperature but liquifies at 98°C. Sodium is a solid at room temperature but liquifies at 98°C. It has a wide working temperature since it does not boil until It has a wide working temperature since it does not boil until

892°C.892°C.– That brackets the range of operating temperatures for the reactor That brackets the range of operating temperatures for the reactor

so that it does not need to be pressurized as does a water-steam so that it does not need to be pressurized as does a water-steam coolant system. coolant system.

– It has a large specific heat so that it is an efficient heat-transfer It has a large specific heat so that it is an efficient heat-transfer fluid. fluid.

The Super-PhenixThe Super-Phenix

The Super-Phenix was the first large-scale breeder reactor. It The Super-Phenix was the first large-scale breeder reactor. It was put into service in France in 1984. was put into service in France in 1984.

The reactor core consists of thousands of stainless steel tubes The reactor core consists of thousands of stainless steel tubes containing a mixture of uranium and plutonium oxides, about containing a mixture of uranium and plutonium oxides, about 15-20% fissionable plutonium-239. Surrounding the core is a 15-20% fissionable plutonium-239. Surrounding the core is a region called the breeder blanket consisting of tubes filled only region called the breeder blanket consisting of tubes filled only with uranium oxide. The entire assembly is about 3x5 meters with uranium oxide. The entire assembly is about 3x5 meters and is supported in a reactor vessel in molten sodium. The and is supported in a reactor vessel in molten sodium. The energy from the nuclear fission heats the sodium to about energy from the nuclear fission heats the sodium to about 500°C and it transfers that energy to a second sodium loop 500°C and it transfers that energy to a second sodium loop which in turn heats water to produce steam for electricity which in turn heats water to produce steam for electricity production. production.

Such a reactor can produce about 20% more fuel than it Such a reactor can produce about 20% more fuel than it consumes by the breeding reaction. Enough excess fuel is consumes by the breeding reaction. Enough excess fuel is produced over about 20 years to fuel another such reactor. produced over about 20 years to fuel another such reactor. Optimum breeding allows about 75% of the energy of the Optimum breeding allows about 75% of the energy of the natural uranium to be used compared to 1% in the standard natural uranium to be used compared to 1% in the standard light water reactor.light water reactor.

Nuclear FusionNuclear Fusion In In nuclear fusionnuclear fusion, energy is released when two light nuclei are , energy is released when two light nuclei are fusedfused

together to form a heavier nucleus. together to form a heavier nucleus. This happens on the This happens on the risingrising part of the graph. part of the graph. Nuclear fusion is the principal source of energy in stars and fusion can Nuclear fusion is the principal source of energy in stars and fusion can

happen if each nucleus has sufficient kinetic energy to enable them to happen if each nucleus has sufficient kinetic energy to enable them to overcome their mutual repulsion, be captured by the strong nuclear force overcome their mutual repulsion, be captured by the strong nuclear force and stick together. and stick together.

The minimum temperature required to initiate a fusion reaction is 4.0 x10The minimum temperature required to initiate a fusion reaction is 4.0 x1088 K.K.

In star formation, the kinetic energy to do this comes from the conversion In star formation, the kinetic energy to do this comes from the conversion of gravitational energy into thermal energy by the Kelvin Helmholtz of gravitational energy into thermal energy by the Kelvin Helmholtz contraction. contraction. – In the case of stars like the sun, fusion can occur when the temperature of the In the case of stars like the sun, fusion can occur when the temperature of the

contracting cloud reaches about 8 x 10contracting cloud reaches about 8 x 1066 K. K. – It is because of the high temperatures which are needed to give the protons It is because of the high temperatures which are needed to give the protons

sufficient kinetic energy, that these nuclear reactions are also known as sufficient kinetic energy, that these nuclear reactions are also known as thermonuclearthermonuclear fusion reactions. fusion reactions.

It is fusion of hydrogen nuclei by thermonuclear fusion reactions It is fusion of hydrogen nuclei by thermonuclear fusion reactions with a release of binding energy that is the primary source of with a release of binding energy that is the primary source of energy generation in stars.energy generation in stars.

The Tokamak ReactorThe Tokamak Reactor To satisfy the conditions of thermonuclear fusion, using To satisfy the conditions of thermonuclear fusion, using

deuterium-tritium fuel, deuterium-tritium fuel, – the the plasma temperatureplasma temperature TT must be in the range 1~3×108 K, must be in the range 1~3×108 K, – the the energy confinement timeenergy confinement time tEtE must be about 1~3 s and must be about 1~3 s and – the the densitydensity nn must be around 1~3×1020 particles/m3. must be around 1~3×1020 particles/m3.

To startup a reactor some means of auxiliary heating must To startup a reactor some means of auxiliary heating must be used to attain the minimum initial temperature of about be used to attain the minimum initial temperature of about 108 K. 108 K. – After the ignition of the fuel mixture the plasma will be heated After the ignition of the fuel mixture the plasma will be heated

by the alpha-particles released in the reaction and the source by the alpha-particles released in the reaction and the source of auxiliary heating may be turned off. of auxiliary heating may be turned off.

The rate of fusion reactions increases with the square of the The rate of fusion reactions increases with the square of the plasma density. plasma density. – However, the density cannot increase above certain limits However, the density cannot increase above certain limits

without spoiling the plasma stability. without spoiling the plasma stability. – On the other hand, the energy confinement time increases On the other hand, the energy confinement time increases

with the density, with the degree of plasma stability, and with with the density, with the degree of plasma stability, and with the plasma volume. the plasma volume.

– Balancing these requirements, it is possible to determine the Balancing these requirements, it is possible to determine the minimum sizeminimum size for a reactor, which depends on the magnetic for a reactor, which depends on the magnetic configuration adopted. configuration adopted.

http://w3.pppl.gov/~dstotler/SSFD/http://w3.pppl.gov/~dstotler/SSFD/

How much energy is released How much energy is released during thermonuclear during thermonuclear

reactions?reactions? 4H 4H He + energy released He + energy released

mass of 4 H atoms = 4 x 1.008 = 4.032 amumass of 4 H atoms = 4 x 1.008 = 4.032 amu

- mass of 1 He atom = 4.003 amu- mass of 1 He atom = 4.003 amu

therefore... mass defect = 4.032 - 4.003 = 0.029 therefore... mass defect = 4.032 - 4.003 = 0.029 amuamu

Using the mass-energy relation, the mass Using the mass-energy relation, the mass converted into energy isconverted into energy is

= (0.029 amu x 1.66 x 10= (0.029 amu x 1.66 x 10-27 -27 kg/amu) x (3 x 10kg/amu) x (3 x 108 8 m/s)m/s)22

= 4.33 x 10= 4.33 x 10-12-12 J or, equivalently, 27 MeV. J or, equivalently, 27 MeV.

Trinity 1945Trinity 1945

On July 16, 1945, at 5:29:45 a.m., the On July 16, 1945, at 5:29:45 a.m., the first atomic explosion in history took first atomic explosion in history took place at the Jornado del Muerto (Journey place at the Jornado del Muerto (Journey of Death) trail on the Alamagordo of Death) trail on the Alamagordo Bombing Range in New Mexico. An Bombing Range in New Mexico. An extremely tense group of scientists extremely tense group of scientists looked on as the bomb, named looked on as the bomb, named "Gadget," released its 18.6 kiloton yield, "Gadget," released its 18.6 kiloton yield, vaporizing the 100-foot steel tower it vaporizing the 100-foot steel tower it had been hoisted atop. had been hoisted atop.

A-Bomb: The Nevada Test A-Bomb: The Nevada Test

Test Able: Test Able: An Air Drop in the Bikini IslandAn Air Drop in the Bikini Island

Test Baker: Test Baker: An Underwater Detonation at An Underwater Detonation at

the Bikini Atollthe Bikini Atoll

Nuclear FalloutNuclear Fallout

The National Cancer Institute recently The National Cancer Institute recently estimated that 10,000-75,000 cases of estimated that 10,000-75,000 cases of thyroid cancer in the United States were thyroid cancer in the United States were caused by the radioactive isotope iodine-131 caused by the radioactive isotope iodine-131 from Nevada A-bomb fallout. from Nevada A-bomb fallout.

In addition to the military personnel exposed In addition to the military personnel exposed to high levels of radiation in the vicinity of to high levels of radiation in the vicinity of the tests, thousands of U.S. citizens the tests, thousands of U.S. citizens downwind may have paid a lethal price for downwind may have paid a lethal price for the atomic ambitions of their own the atomic ambitions of their own government. government.

Project Ivy: Project Ivy: Hydrogen Test BombHydrogen Test Bomb