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Chapter 16/17 RAD GuideApril 19, 2023
NUCLEAR ENERGY
Atomic Model s
Atomic Model (cont) Atomic consists of:
Protons ( + charge) Nuetrons (neutral charge) Electrons (- charge)
Protons and neutrons makes the nucleus Majority of atomic mass is in the nucleus Electrons orbit the nucleus
Atomic Number & Mass Number Atomic number: the number of protons in an
atom. Example: if oxygen has 8 protons, what is
oxygen’s atomic number? Mass number: the number of protons plus
the number of neutrons in an atom. We neglect electrons for mass number because
mass of electrons is negligible.
Isotopes s
Isotopes (cont)
Atoms of the same element that have different numbers of neutrons are called isotopes.
This means that isotopes of the same element will have different mass numbers.
Note: the number of protons in isotopes are always the same.
Radioactivity Unstable atoms decay, emitting particles and
energy from the nucleus. After a series of decay changes, a radioactive
element becomes stable.
Types of Particles Emitted from Unstable Nuclei (Radiation)
Alpha particles (α): decay that gives off 2 protons and 2 neutrons
Beta particles (β): decay that gives off an electron, converting a neutron into a proton
Gamma (γ) radiation: form of electromagnetic radiation. A large burst of energy.
Question Do these emissions alter an element’s …
Atomic number? Mass number?
Half-Life The amount of time it takes for half of the
atoms in a sample of radioactive material to decay.
Reactions and Reactors d
Nuclear Fission
Energy holds the protons and neutrons in an atom’s nucleus together.
Question: what would happen if we were to split the nucleus of an atom apart?
Nuclear Fission: Reaction in which the nucleus of a large atom is split into smaller nuclei.
Uranium -235 Chain Reaction most commonly used in nuclear reactors.
Structure & function of nuclear power plant. Fission of U-235 in reactor vessel heats
H2O steam turns turbines energy stored in generator used as electricity
Water circulates between fuel rods, acting as a coolant and slowing neutrons.
control rods control how fast or slow reaction occurs
Nuclear Power Plant
Breeder Reactors
Radioactive Waste Harmful to living organisms
Immediate effect: skin burns, anemia, death
Long term effect: changes in DNA, leading to cancer & genetic mutations
Radioactive Waste High-level wastes
Emit large amounts of radiation. Uranium fuel rods, control rods, coolant water.
Medium/Low-level wastes large volume of this type of waste is generated. Most common Effects may not be immediately noticeable.
Nuclear Waste Disposal High level wastes
Stored in tanks outside power plants Tanks often leak, leading to contaminated site.
Low/medium level wastes Often buried Enclosed and dropped into oceans.
Nuclear Waste Disposal Issues in finding permanent disposal method:
Long half-lives hazardous/poisonous. Wastes must be sealed in containers that will
never corrode Containers often leak into environment Waste sites must be geologically stable. Deep underground storage is highly expensive.
Nuclear Meltdown If the cooling and control systems in a reactor
core fail, the chain reaction becomes uncontrollable and melts reactor core.
Nuclear Meltdown
Chernobyl Disaster d
Solar Energy d
The Sun Source of almost all the energy on Earth’s
surface Ecosystems Water Cycle Causes the winds to blow
Ecosystems s
Water Cycle dd
Wind d
Thermonuclear Fusion d
Solar Energy Harnessing the sun’s energy to generate heat
and electricity. Advantages
renewable, nonpolluting. Disadvantages
Energy source is not constant Equipment is not size and cost efficient.
Passive Solar Energy Passive: sun’s energy is
collected, stored, & distributed naturally in enclosed dwelling Not used to produce electricity,
but reduces the need for it. Achieved through building
design and positioning. Ex: Greenhouse
Passive Solar Energy (cont) d
Passive Solar Energy (summary) South facing windows Building materials that absorb solar energy Glass-enclosed areas Dark colored walls and floors Good insulation Thick, heavy curtains or shutters.
Active Solar Energy Active: devices are used to
collect, store, and circulate heat produced from solar energy.
Types Flat-plate solar collectors Photovoltaic cells
Flat-Plate Solar collectors d
Flat-Plate Solar Collectors d
Solar One in Mojave Desert, CA. d
Photovoltaic (PV) Cells Only solar energy device that produces
electricity directly. Uses thin wafers of semiconductor material.
Silicon or selenium Structure:
Two thin slices of semiconductor material joined. Sunlight striking the cell causes electrons to move
from one slice to the other, resulting in an electric current.
PV Cells (cont) s
PV Cell (cont) Uses
Solar powered Calculators Solar powered watch Electricity for homes, industry, automobiles
Advantages Light weight No wastes or pollutants No moving parts Do not consume any materials
Hydroelectric Energy d
Dams Flowing Water
Water behind dam is directed at the turbine blades Water pushes against the turbine blades, causing them
to turn. (kinetic energy to mechanical energy) Mechanical energy of the turbine is transferred to coils
within a generator The coils spin through a magnetic field, producing
sent electricity
Function of Dams d
Advantages of Dams Renewable Controls flow of water
Flood control Navigation of Boats
Reservoirs Recreation areas (fish, boat, swim) Store water (irrigation and home use)
Disadvantages of Dams Changed water depth and flow alters natural plant
& animal life Shoreline can flood, leading to erosion & change
ecosystems Fish caught in turbine blades Prevent salmon from completing reproductive
cycle Stored water released into downstream water
causes changes a rapid change in temp
Tidal Energy (still hydroelectricity) High and low tides cause turbines to turn in
both directions generating electricity.
Tidal Energy Disadvantages In most regions, the difference between high
and low tide is insufficient to power a generator
Equipment damages surrounding wetlands Affects local ecosystems.
Wind Energy d
Aerogenerator
Windmills that are used to generate electricity (wind turbine generators)
Aerogenerators Winds causes blades to turn energy is stored in generator sent out as electricity Types
1. Blades on horizontal (like airplane)
2. Blades on vertical (like eggbeater) Used for calmer conditions
Wind Farms d
Advantages of Wind Power Renewable Free Unlimited nonpolluting
Disadvantages of Wind Power DISADVANTAGES
Not always windy enough Wins farms Require a lot of land Interferes with radio & TV signals Impact wildlife Ugly (?)
Geothermal Energy
Heat Source Radioactive decay of elements deep beneath
the ground. This decay gives off heat
lava, geysers steam vents, hot springs, & bubbling mud.
Hot Rock Zones 1.Hot water is pumped from deep underground through a
well under high pressure. 2.When the water reaches the surface, the pressure is
dropped, which causes the water to turn into steam. 3.The steam spins a turbine, which is connected to a
generator that produces electricity. 4.The steam cools off in a cooling tower and condenses
back to water. 5.The cooled water is pumped back into the Earth to
begin the process again.
Hot Rock Zones d
What are some advantages & disadvantages to using geothermal?
ADVANTAGES DISADVANTAGES1. Not easy to find
2. Most areas have very little geothermal heat at surface, and it’s not worth extracting.
3. Hydrogen Sulfide gas pollutes the air.
4. Minerals and salts corrode pipes.
5. Lack local H2O supply for steam production.
Recall: Thermonuclear Fusion d
Nuclear Fusion using Deuterium
Nuclear Fusion Recall: Occurs when 2 atomic nuclei fuse to
become one larger nucleus The fuel for nuclear fusion reactions is deuterium
(H-2 isotope of hydrogen). Fuel is readily available in seawater Fusion produces much less waste than fission, and
produces enormous amounts of energy However, scientists are still learning how to
harness this energy source efficiently.
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