Nuclear Chemistry

Nuclear•What do you think about when you hear

the word nuclear?

Nuclear•What are some problems with nuclear

power? Can you think of any problems that may arise with using nuclear power? Do you have any solutions to these problems?

Radiation• Types of Radiation• Radioactivity - Atoms can change spontaneously because they

have unstable nuclei• Electromagnetic radiation - energy emitted during radioactive

decay▫ ex. Visible light, microwaves, radio waves, and x-rays

• Properties of EM radiation▫ has no mass▫ travels at the speed of light▫ movement does not depend on a medium, (can travel through a

vacuum)▫ emitted by atoms as they decay or become energized (light bulb)▫ moves in bundles called photons (characteristic frequency)▫ the higher the frequency, the higher the energy

Radiation• Ionization radiation - highest energy and greatest

potential for harm (x-rays, gamma rays, nuclear decay), energy is transferred to the electrons, so electrons get ejected from molecules causing the molecule to become an ion

• Nonionizing radiation - lower energy (uv, visible, and radio waves) causes excitation, molecules vibrate or electrons move to higher energy levels, excessive exposure can be harmful

Radiation•"all radiation is harmful and should be

avoided" discuss this statement with your partner

Nuclear Power•The Benefits and Risks of Nuclear Power

•Every new form of technology has a certain risk associated with it

•People continue to use the technology to reap the benefits as long as they outweigh the risks▫ex. Fire, Dams, Boats, driving, health care, and

honestly almost everything was once believed to be too dangerous to use, however, over time people started to realize the benefits

MN Nuclear Power

Benefits•Healthcare - tracers are used to trace

abnormalities in body functions, to located damaged areas, and in therapy

•Irradiators - used to kill harmful cells in the body, as well as in sterilizing food, and medical equipment

Risks• Radiation Exposure - people are exposed to radiation on a daily

bases from background radiation as well as:• Cosmic Rays - from outer space• Radioisotopes - from rocks and minerals in the earth's crust, as

well as in the atmosphere (radon decays naturally in the ground and produces radon)

• Nuclear Weapon Testing - depending on where you live• Traveling in Airplanes - closer to cosmic rays• Medical equipment - mostly X rays but other sources as well• Radioisotopes - from generating nuclear power and other

nuclear technologies• The average person receives more than 170 mrem of radiation

per year, some receive up to 5 rem per year but have an increased chance of getting cancer by 1-3%

Storage•Imagine that you are living the way that

you do now, but you can't through away any of your garbage. What would you do? What would happen to your lifestyle?

Nuclear Power Plants in the U.S.

• A group of tourists walking into the Storage Facility

Opposition to Yucca Mountain Disposal Site

Nuclear vs Coal

Prairie Island Nuclear Power Plant

High level Nuclear Waste (Wet) Storage (fuel rods)

Dry Cast Storage of Nuclear Wastes

DryCast Storage Pad

High level Nuclear Waste (Dry Cask) Storage

Conceptual diagram of the Yucca Mountain facility

Opposition to Yucca Mountain Disposal Site

NUCLEAR POWER TIMELINE1946 Atomic Energy Act passed creating

AEC1957 Price Anderson Act passed1960-80 Many US nuclear plants

constructed1970s: increasing anti-nuclear activism1978:

• Three Mile Island accident• China syndrome

1986: Chernobyl

Allen S KingLocation: MNOperator: Xcel EnergyConfiguration: 1 X 598 MWOperation: 1968Fuel: coalQuick facts: The Xcel Energy power plant nesting project began in 1989, when the Allen S King plant became the first power plant in the United States to provide a home for nesting peregrine falcons.

Coal power chute

Recent IPCC data on emissions

GLOBAL WARMING

CO2 EMISSIONS

FUTURE EFFECTS

Is the climate changing?

If so, are CO2 the principal cause?

Will the costs of global warming exceed the benefits?

Will the benefits of stopping or slowing global warming exceed the costs?

Global Warming: Hypothesized Relationship

What does the future hold for coal-fired and nuclear power?

Will we continue to rely on either or both for base load electricity? Should we?

Are the environmental costs of these technologies acceptable?

Should we promote these technologies? Phase them out? Let the market decide?

Nuclear Discovery• W.K. Roentgen - used cathod ray tubes to study

fluorescence (glow in the dark), and discovered x-ray

• Henri Becquerel - studied fluorescence in minerals using x-rays. Randomly tested uranium and discovered its penetrating power, and radioactivity had been discovered

• Pierre and Marie Curie - suggested that radioactivity might be a property of heavy elements

Rays• Nuclear Radiation - • Alpha rays - deflect in the negative direction

because they consist of positively charged particles

• Beta rays - deflect in the positive direction because they consist of negatively charged particles

• Gamma rays - are not deflected, higher energy radiation

• Gold Foil Experiment

Architecture of Atoms• Nucleus is made up of _____________ and _____________

• __________ are positively charged

• __________ are negatively charged

• __________ are not charged

• These are classified as subatomic particles

• Isotopes are _____________________________________________________

• Radioisotopes - isotopes with unstable nuclei and is radioactive

• Atomic Mass is the weight of the ___________ and ______________

• Atomic number is the __________________________

Isotope Notation•top number is the mass number•bottom number is the atomic number•symbol is the element•naming it - you say the element with the

mass number • ex

Examples

Radioactive Decay

•There are 350 isotopes found in Nature and 70 are radioactive

•Geiger Counter - tool used to detect radioactivity

•Background radiation - A constant quantity of natural radioactivity is always present in our environment

Natural Decay• Alpha particle - made of two protons and two neutrons

(nucleus of a Helium atom)▫ 8,000 times more massive than a beta particle▫ Poor penetrating power (cannot penetrate skin)

• Radium 226 ---------> Alpha particle + Radon 222

• Atoms are not conserved, but the sum of the mass numbers and the sum of atomic numbers are

Natural Decay• Beta Particles - Neutron is transformed into a proton and an

electron, the proton remains in the nucleus and the electron is ejected at high speeds▫ Very fast moving▫ Very small▫ Extremely high penetrating power

• Neutron ---------> Proton + Beta Particle

• Lead 210 ---------> Bismuth 210 + Beta Particle

• Sum of mass numbers and the sum of atomic numbers remains the same

Decay• Gamma Rays - Very high energy electromagnetic

radiation▫the most penetrating▫have no mass and no charge so there is no equation

• Many times the isotopes produced in radioactive decay are still radioactive and continue to decay in a chain reaction

• ex. U-238 ---> U-235 -----> U-232 ------> 13 Steps------> Stable form of lead

Summary•Alpha particles - Cause lots of damage at

short distances but are easily blocked (helium nucleus)

•Beta and gamma particles - less damage over large distances but difficult to shield (electron)

Nuclear Terms•Artificial Radioactivity - this is how

synthetic elements are made▫have an artificial nucleus

•Transmutation - conversion of one element into another

•Particle Accelerator - produced bombardment reactions needed to make synthetic elements

Decay•Half Life - the measurement of the rate of

decay▫it is the amount of time that it takes for half

of the radioactive material to decay▫can range from milliseconds to billions of

years▫no way to speed up the process (this is why

nuclear waste is such a controversy)▫after 10 half lives the activity would be

1/1000th or .1% of the original material

Half Life• Starting material - 100%• First half life - 50%• Second half life - 25%• Third half life - 12.5%• Fourth half life - 6.25%• Fifth half life - 3.125%• Sixth half life - 1.5625%• Seventh half life - .78125%• Eigth half life - .39o625%• Ninth half life - .1953125%

Half Life•Half life of 14C = 5730 years•Every living thing has a constant amount of

14C in it, when it dies this amount goes down•Comparing actual amount to amount it

should have when living allows us to estimate the % of 14C left

•Convert the % into number of half lives and half lives into years to find the age of a fossil

•M = Original Mass X (1/2) ^t▫t = number of half lives

Bombardments• Bombardments - making synthetic elements

▫ Target Nucleus - the stable isotope that is bombarded in the experiment▫ The Projectile - is the particle that is fired at the target nucleus▫ The Product - the heavy nucleus produced in the reaction▫ The Ejected Particle - the light nucleus or particle emitted from the

reaction

• Helium-4 + Nitrogen-14 -------> Oxygen-17 + Hydrogen-1

• Ex. that is used with a particle accelerator• bombarding aluminum with alpha particles, producing radioactive

phosphorus-30 and a neutron

Test•36 MC questions•6 definitions•8 Matching•3 Short Answer/equations•1 Conversion•Nuclear Power Plants vs Coal Power Plants•Nuclear Power Plants, chernobyl, 3MI•Alpha, Beta, Gamma•Isotopic Notation