fission and fusion

Fission and fusionU-235 binding energyNuclear power plantsAdvantages and disadvantagesNuclear disasters

30 May 2012

11 Physics

U-235 binding energy per nucleonCalculate the binding energy per nucleon where the mass of a U-235 nucleus is 235.0439299 u.

Image: http://en.wikipedia.org/wiki/Uranium-235

Binding energy per nucleon

Nuclear fusion

Nuclear fission

The sun

Nuclear power plantThermal power plantUses a nuclear chain reaction

Image: http://en.wikipedia.org/wiki/Nuclear_power_plant

Uranium fuelNatural uranium ore (pitchblende,

uranium oxide) is a mix of isotopes:

99.3% U-2380.7% U-235

(Plutonium-239 canalso be used as fuel)

not enough U-235 for a chain reaction

Image:http://en.wikipedia.org/wiki/Uranium_ore

Critical mass: minimum size for a nuclear chain reaction to occur11kg Pu-

23952kg U-

235

image: http://en.wikipedia.org/wiki/Critical_mass

Mk-54 SADM (Special Atomic Demolition Munition). The bare warhead package was an 28 cm by 41 cm cylinder that weighed 23 kg. Image: http://en.wikipedia.org/wiki/Suitcase_nuke

PhET simArtificial transmutation:

10n + 235

92U 23692U

Nuclear chain reaction with U-235, eg:

23692U 137

55Cs + 9637Br + 3 1

0nIsotopic enrichment to 5% U-235Containment vesselControl rods

Nuclear power plant

ModeratorControl rodsReactor vesselHeat exchangerTurbineGenerator

Image: http://en.wikipedia.org/wiki/Nuclear_power_plant

Advantages and disadvantages high energy density large uranium reserves

in Australia, Canada, Kazahkstan

does not depend on weather, time of day, etc.

Radioactive waste Accident (thermal

meltdown) Terrorist target Non-renewable Mining and transport of

fuel difficult and expensive

Expensive to builld plant

Nuclear technology proliferation

Pu-239 created as waste product- could be used for weapons

Nuclear accidents: Chernobyl 1986

31 workers died from acute radiation sickness

thousands (?) of extra cancer deaths, particularly from thyroid cancer

power surge containment vessel rupture graphite moderator exposed to air fire

Image: en.wikipedia.org/wiki/Chernobyl_disaster

Nuclear accident: Fukushima 2011

Image: http://en.wikipedia.org/wiki/Fukushima_I_nuclear_accidents

tsunami flooding of control rooms coolant systems not working meltdown build up of hydrogen gas explosion

0 workers died from acute radiation sickness (though some were drowned in tsunami)

dozens (?) of extra cancer deaths (not from thyroid cancer)

Nuclear power plantShort (3 slide max, 4 min) presentation including information about: cooling system, fuel, moderator, control rods, waste, safety systems

diagrams and nuclear equationsreferencesAGR, PWRBWR, fast breeder

LinksPhET nuclear fissionhttp://

phet.colorado.edu/en/simulation/nuclear-fission