Fission and Fusion

Atomic FissionAtomic Fission Nuclear fission occurs when a heavy Nuclear fission occurs when a heavy

nucleus such as U-235 splits into two nucleus such as U-235 splits into two smaller nuclei.smaller nuclei.

The total rest mass of the products is The total rest mass of the products is less than the original rest mass.less than the original rest mass.

The mass difference is converted to The mass difference is converted to the energy released using e=mcthe energy released using e=mc22

This process occurs naturally at a This process occurs naturally at a slow rate, but can be accelerated by slow rate, but can be accelerated by neutron bombardment in the neutron bombardment in the laboratory.laboratory.

Neutron Bombardment of U-Neutron Bombardment of U-235235

U-235 absorbs a U-235 absorbs a slow moving slow moving neutron.neutron.

U-236 is unstable U-236 is unstable and lasts for only and lasts for only 1010-12-12 s. s.

The U-236 The U-236 nucleus splits into nucleus splits into two fragments two fragments and emits several and emits several neutrons.neutrons.

UnU 23692

10

23592

neutronsYXU 23692

nKrBaU 10

9236

14156

23692 3

Nuclear FusionNuclear Fusion Lighter nuclei undergo a process Lighter nuclei undergo a process

called nuclear fusioncalled nuclear fusion Fusion takes a great amount of energy Fusion takes a great amount of energy

to be initiated in order to overcome to be initiated in order to overcome the proton-proton barrier between the proton-proton barrier between nuclei.nuclei.

However, a greater amount of energy However, a greater amount of energy is released in the process.is released in the process.

Stars produce their energy through Stars produce their energy through the fusion process.the fusion process.

Fusion ProcessFusion Process Hydrogen is fused Hydrogen is fused

together forming together forming deuterium.deuterium.

He-3 is formed He-3 is formed from hydrogen from hydrogen isotopes.isotopes.

He-4 is formed He-4 is formed through 2 through 2 different different processes.processes.

The energy is The energy is produced though produced though the gamma, the gamma, neutrino, and neutrino, and positron positron emission.emission.

eHHH 01

21

11

11

HeHH 32

21

11

eHeHeH 01

42

32

11

HHHeHeHe 11

11

42

32

32

Nuclear Power Plants USANuclear Power Plants USA

Nuclear FactsNuclear Facts Nuclear energy is energy that is released Nuclear energy is energy that is released

either by splitting atomic nuclei or by either by splitting atomic nuclei or by forcing the nuclei of atoms together.forcing the nuclei of atoms together.

Nuclear energy comes from mass-to-Nuclear energy comes from mass-to-energy conversions that occur in the energy conversions that occur in the splitting of atoms. splitting of atoms.

Nuclear energy is produced by a Nuclear energy is produced by a controlled nuclear chain reaction and controlled nuclear chain reaction and creates heat—which is used to boil water, creates heat—which is used to boil water, produce steam, and drive a steam produce steam, and drive a steam turbine. turbine.

Nuclear FactsNuclear Facts

Nuclear power can come from the Nuclear power can come from the fission of uranium, plutonium or fission of uranium, plutonium or thorium or the fusion of hydrogen into thorium or the fusion of hydrogen into helium. Today it is almost all uranium. helium. Today it is almost all uranium.

Nuclear power plants need less fuel Nuclear power plants need less fuel than ones which burn fossil fuels. One than ones which burn fossil fuels. One ton of uranium produces more energy ton of uranium produces more energy than is produced by several million than is produced by several million tons of coal or several million barrels tons of coal or several million barrels of oil. of oil.

Nuclear FactsNuclear Facts

In France, nuclear power is the most In France, nuclear power is the most widespread, supplying 80 percent of the widespread, supplying 80 percent of the country's electricity. country's electricity.

As of 2004, nuclear power provided 6.5% As of 2004, nuclear power provided 6.5% of the world's energy and 15.7% of the of the world's energy and 15.7% of the world's electricity, with the U.S., France, world's electricity, with the U.S., France, and Japan together accounting for 57% of and Japan together accounting for 57% of nuclear generated electricity. nuclear generated electricity.

Nuclear energy (nuclear power) accounts Nuclear energy (nuclear power) accounts for about 19 percent of the total electricity for about 19 percent of the total electricity generated in the United States.generated in the United States.

Why Not?Why Not?

Basic Components Nuclear Basic Components Nuclear PlantPlant

Are You Exposed?Are You Exposed?

Yearly Dosage of RadiationYearly Dosage of Radiation

Limiting ExposureLimiting Exposure

HomeworkHomework

Pg 695-696 [34-42]Pg 695-696 [34-42]