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Harnessing energy of the atomic nucleus (Nuclear Fusion (Better than…
Harnessing energy of the atomic nucleus
Radioactive Decay
Nuclei
Contain nucleons
Protons and neutrons
Held by strong nuclear force
stronger than elctrostatic force
Push protons apart in the nucleus
Short range
Drops to zero at 2.5*10^-15m
More protons increase force of attraction on nucleons
Adds to electrostatic repulsive force
On the other side of the nucleus
Protons too far to experience stronge nuclear force
Causes individual nucleons to combine
Form nucleus
Nucleus mass<constituent nucleons
Mass defect
Lost energyy becomes energy released
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Binding energy per nucleon
Energy to remove nucleon from a nucleus
Measure of stability of nucleus
Atomic mass (A)
Nucleon number
Atomic Number (Z)
Proton number
Neutron number (N)
N=A-z
Unstable Nucleus
Releases particles and energy until stable
Particles emitted
More energetic than photons emitted from electrons
Ionising radiation
Radiation energetic enough to ionise material it passes through
Daughter nucleus
Product of unstable nucleus
Lower mass than parent nucleus
Mass defect
Mass lost is converted into energy
Einstein's Mass-energy equivalence equation
E=mc^2
Law of conversation of energy
Radioactive
Spontaenous emission of particles form the nucleus
Parent nucleus
Proton to neutron ratio is not stable
Nucleus is too large
All elements heavier than lead
Radioactive isotope
Isotope
Two or more forms of element
Same nubmer of protons
Different number of neutrons
Occur in three ways
Emit alpha particle
Helium Nuclei
Positively charged
+2 Charge
Contain two proton + two neutrons
Properties
Ionising Power
High ionising power
Penetrating Power
Low penetrating power
A few sheets of paper
Range in air
Only a few centimetres in air
Alpha Decay
Result in unstable element transmuted to a different element
Insert sample reaction here
Spontaneous transmutation
Emit Beta particle
Beta minus sign
Neutrons in parent nucleus decay into a proton
High-speed electron is ejected
2/3 speed of light
Reduce neutron to proton ratio
Atomic number of daughter nuclide icnreases by 1
Antineutrino emitted
small neutral particle
Insert sample equation
Properties
Ionising Power
Medium
Less than Alpha
Penetrating Power
up to 3mm of aluminium
Higher than Alpha
Rage in Air
Around a metre
Difficult to determine
Beta plus sign
Positron emission
Proton converted into a neutron
Increses neutron to proton ratio
Accompanied by emission of nuetrino
Not naturally occuring
Change radioactive isotope into different element
Spontaneous transmutation
Emit Gamma ray
Energetic photons
High frequency
Emitted after alpha or beta decay
Remove excess energy from nucleus
Properties
Ionising Power
Poor ionisers
Penetrating Power
Highest penetrative power of radioactive particles
Penetrate up to 30cm of steel
Range in air
Penetrate hundres of metres
Does not change number of protons
Does not change parent atom to a different element
Insert equation here
Interaction with electric and magnetic fields
Electric
Alpha
direction of field
Beta+
direction of field
Beta-
accelerated in the opposite direction
Half Life +Decay
Time it takes for half a nuclei to undergo radioactive decay
Random event
Hard to predict
Similar to calculating probability
Active sample
Short half life
Less active sample
long half-life
Insert equation and what shit means
Nuclear Fission
heavy nucleus splits into two smaller nuclei
Products mass<parent nuclei
Mass lost is converted into energy
Einstein's mass-energy equivalence equation
E=mc^2
Law of conservation
Binding energy emitted
Energy required to break down a nucleus
Mass defect
Heavy
Z>56
Neutrons released
Energy stored as binding energy released
Energy holding a nucleus together
2-3
Trigger further fissions in surrounding nuclei
Chain fission reaction
Triggered by nucleus absorbing a neutron
Nucleus becomes unstable
Nucleus splits apart
Neutron collides with nucleus
artificial transmutation
changing chemical element into another
Using artificial means
Controlled chain fission reaction
Energy Released
Neutrons released
Kinetic energy
Daughter nuclei
Kinetic nuclei
Mass defect
binding energy
Run at a constant rate
Each fission initiates one more fission
Performed in a nuclear power station
Fuel
Enriched Uranium
3.5-4.5%
In the form of Uranium oxide rods
Increased proportion of Uranium-235
Separate uranium-235 out of naturally occuring urnamium ore
Separated amount put back into naturally occuring uranium
Isotope enrichment
Increasing percentage of specific isotope in sample
Neutron Moderation
Slow down neutrons
Higher probability of being absorbed than fast neutrons
Increase probability of fission reaction
Material with nuclides
Slightly larger mass than neutron
Hydrogen
Deuterium
Tritium
Neutrons share energy with nuclides
Through collisions
Decrease in energy
Move slower
Increased probability of neutron colliding with Uranium-235
Reactor Vessel
Critical mass
Minimum mass required to sustan a fission chain reaction
In solid sphere of fissionable material
Optimal surface area: volume ratio
made of hig nucleon number material
Neutrons are reflected back into smaple
Control Rods
Boron or Cadmium
Absorb Neutrons
Control the reaction rate
Coolant
Absorb heat generated by chain reactor
Water cooling
Waste
Uranium
Heavy atom
High neutron to proton ratio
Daughter products high in neutrons
Radioactive
1/3 of spent fuel rods
Removed from reactor core
Every year
Uncontrolled chain fission reaction
runs at an increasing rate
Each fission initiates more than one fission
Nuclear Fusion
Two nuclei come together to form a large nucleus
High energy input required
Overcome elctrostatic replusion between nuclei
Bring nuclei close enough together
Strong nuclear force bind nucleons together
Use high temperatures
High temperature
Artifical transmutation
Mass of large nucleus<constituent nuclei
Mass defect
Lost mass transformed into energy
Law of conservation of energy
Einstein mass-energy equivalence equation
Binding energy emitted
Energy required to split nucleus into constituent nucleons
Uncontrolled fusion
Used in thermonuclear weapon
Hydrogen bombs
Uncontrolled fission reaction produces high temperatures
Start fusion reaction
More energy produced than fission reaction
Naturally occuring in stars
Sun
Hydrogen fusion
Proton-Proton chain
Harness energy from Fusion reaction
Solar power
Spontaenous transmutation
Better than Fission
More energy released
Produce less radioactive material
Nearly unlimited fuel supply
Hydrogen