Transcript Chapter 16

Chapter 16
Fusion and Fission
– and a new energy
Nuclear Fusion: A nuclear reaction in
which two nuclei combine to form a single,
larger nucleus. Nuclear energy is released
whenever two light nuclei are fused to
create a nucleus that is lighter than iron
 Nuclear Fission: A nuclear reaction in
which a large, single nucleus splits into
two roughly equal smaller nuclei. Nuclear
energy is released whenever a heavy
nucleus is fissioned into two nuclei that
are both heavier than iron
 Nuclear Energy: The energy resulting
from the structure of a material’s nuclei

16.1 Fusion: Fire of the Sun
The Release of Nuclear Energy is the
transformation of nuclear energy into
thermal or radiation
 A self-sustaining fusion reaction has
thermal energy, so it is called a
Thermonuclear Reaction

16.1 Fusion: Fire of the Sun
Nuclear Energy Curve
A graph showing the energies of the
different nuclei versus their mass number.
The graph shows a lowest point at mass
number 56 (iron), indicating that nuclear
energy can be released by the fusion of
nuclei lighter than iron and by the fission
of nuclei heavier than iron
16.2 The Nuclear Energy Curve
Big Bang
 14 billion years ago
 Created space and time
 Created 3 Elements
◦ Hydrogen
◦ Helium
◦ Lithium (small amount of)
16.3 Origin of the Elements
Fusion processes can create elements
from Helium all the way up to Iron
 Supernova

◦ The explosion of a giant star
◦ Spreads chemical elements into space
◦ Source of elements heavier than Helium
16.3 Origin of the Elements

Chain Reaction: A series of neutroninduced fission reactions that proceed
from one nucleus to the next by means of
the neutrons released during each fission
reaction
16.5 The Chain Reaction
Manhattan Project: The US project
during WWII to build fission bombs
 Fission bombs: A bomb that gets its
energy from a fission chain reaction

◦ Fuel can be either plutonium or a uranium
isotope

Nuclear Reactor: A device to transform
nuclear energy into other energy forms
16.6 The Manhattan Project
Isotope Separation: Any process that
increases the percentage U relative to U
 Centrifuge Separation: An liquid or gas
can be separated into heavier and lighter
portions in a high-speed centrifuge
 Highly enriched Uranium: Uranium that
has been enriched to about 90% U which
is suitable for nuclear weapons use
 Kiliton: A unit of energy, the energy that
would be released by 1000 tons of TNT

235
238
235
16.6 The Manhattan Project
Hiroshima (August 6, 1945)
 Japanese industrial city
 12 kilotons of nuclear energy
 200,000 dead
Nagasaki (August 9, 1945)
 Smaller than Hiroshima
 22 kilotons of nuclear energy
 140,000 dead
16.6 The Manhattan Project
Fusion bombs: A bomb that gets its
energy from the fusion of hydrogen,
triggered by a fission bomb
 Megatons: Unit of energy, equal to 1
million tons of TNT

16.7 Fusion Weapons
Weapons of Mass Destruction: Nuclear,
chemical or biological weapons
 Dirty Bomb: A bomb powered with
conventional explosions that does its
damage primarily by the dispersal of
radioactive materials

16.8 Nuclear Terrorism
4 Routes of Terrorist acquisition of
Nuclear Devices (in order of
plausibility)
◦ Seizing and detonating an intact nuclear weapon
◦ Seizing or purchasing weapons-grade uranium or
plutonium
◦ Sabotaging nuclear power plants and other
nuclear facilities
◦ Acquiring radioactive material leading to building
and detonating a dirty bomb
16.8 Nuclear Terrorism