Transcript Radiation Overview - American Nuclear Society

Atomic Energy Overview
Boy Scout Merit Badge
2006
American Nuclear Society
Schedule
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9:00-9:55
10:00-10:40
10:45-11:25
11:30-12:10
12:15-12:55
1:00-1:40
1:45-2:25
2:30-3:00
Introduction
Station 1
Station 2
Lunch
Station 3
Station 4
Station 5
Wrap-Up/Sign Blue Cards
Blue Cards
Put my name in appropriate spot
Workshop Leader
Address Line 1
Address Line 2
Phone Number
Requirements
1a. Radiation Effects
1b. Drawing of radiation symbol
2. Definitions
3. Scientists
4a. Model of atoms
4b. Fission pictures
4c. Critical Mass
5c. Time, distance and shielding
5f. X-ray facility
5g. Cloud Chambers
6b. US nuclear reactors
7. Nuclear Careers
Brief History of the Atom
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500 BC
Long time
1808 AD
1911
1913
1920’s
Democritus
(Romans  Dark
Dalton
Rutherford
Bohr
Many People
Atom
Ages)
Plum Pudding
Nucleus
Orbits
Quantum Mechanics
So What is an Atom?
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Atoms are made up of protons,
neutrons & electrons
• Protons: + charge
• Neutrons: no charge
• Electrons: - charge
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Atoms want to have no net charge
• #protons = #electrons
Mass of an Atom
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Masses
• Proton: 1 amu
• Neutron: 1 amu
• Electron: .000549 amu
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So mass of atom ~
• #neutrons + #protons
What is the mass of:
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Helium?
• 2 protons, 2 neutrons, 2 electrons
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Oxygen
• 8 protons, 8 neutrons, 8 electrons
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Fissile Uranium
• 92 protons, 143 neutrons, 92 electrons
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Alpha particle
• 2 protons, 2 neutrons
Isotopes
Isotopes are similar elements with
different amounts of neutrons
 There are similar properties
 Some have very different properties
 Stable and unstable versions of
atoms
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Example
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Sodium – 23
• 11 protons, 12 neutrons
• Very plentiful, in salt that you eat (NaCl)
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Sodium – 24
• 11 protons, 13 neutrons
• Not natural
• Highly radioactive, beta decay
• Used to find leaks in industrial pipes
Put together models of:
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Hydrogen
• 1 Proton, 1 electron
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Deuterium
• 1 Proton, 1 neutron, 1 electron
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Tritium
• 1 Proton, 2 neutrons, 1 electron
What are the atomic and mass
numbers of each isotope?
 What are the net charges?
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(Requirement 4a)
Fission vs. Fusion
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Fission
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Makes 20% of our electricity
Breaking apart of Heavy Nuclei
Nuclear Reactor tour later Today!
Example:
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N + U-235  Ba-139 + Kr-94 + 3N
Fusion
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Powers the Sun
Hard to get on Earth
Combination of Light Nuclei
IEC Fusion Tour later Today!
Example:
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H-3 + H-2  N + He-4
Tritium + Deuterium  neutron + Helium
Where does radiation come from?
The sun
 Soil, water and vegetation
 Internal sources
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• Potassium-40 (bananas)
• Carbon-14 (air)
• Lead-210 (radon)
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Man-made sources
• Medical sources (x-rays, radiation…)
• Nuclear Power
Types of Radiation
Ionizing radiation
• Produces ions in the material it strikes
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Non-ionizing radiation
• Can cause damage by physically striking material
Ionizing radiation
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Alpha particles
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Beta particles
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Photons
• Gamma rays
• X-rays
Non-Ionizing Radiation
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Low energy photons
• Such as light, infrared light, etc
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Neutrons
• Neutral particle in nucleus
• Like a proton but with no charge
Radiation Penetration
Radioactive Material
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What is it?
• Material that releases radiation.
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How do we get rid of it?
• When an atom decays, it may or may
not be radioactive still. Eventually, it
will decay to a stable atom
Decay
Radioactive material has a
probability of decaying
 Overtime, this probability averages
into a half life
 Half-life: Amount of time it takes for
half of the radioactive substance to
decay
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Biological Effects of Radiation
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Deterministic
• responses which increase in severity
with increased dose (sunburn)
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Stochastic
• effects which have an increased
probability of occurrence with increased
dose, but whose severity is unchanged
(skin cancer)
Radiation Exposure
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To avoid accidental
exposure, we use the
radiation hazard symbol
Colors
• Magenta or Black
• Yellow Background
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Color one of your own
• Why must people use
radioactive materials
carefully?
(Requirement 1a and 1b)
2006 Atomic Energy Boy
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