Nuclear fission
This presentation is the property of its rightful owner.
Sponsored Links
1 / 36

Nuclear Fission PowerPoint PPT Presentation


  • 40 Views
  • Uploaded on
  • Presentation posted in: General

Revolves around the battle between good nuclear attractive forces and evil electrical repulsion forces . Usually, nuclear forces overpower everything in the nuclei, but in Uranium , repulsive forces nearly rival the nuclear ones.

Download Presentation

Nuclear Fission

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Nuclear fission

Revolves around the battle between good nuclear attractive forces and evil electrical repulsion forces.

Usually, nuclear forces overpower everything in the nuclei, but in Uranium, repulsive forces nearly rival the nuclear ones.

If Uranium’s nucleus is stretched, electrical forces may stretch it further.

If the nucleus stretches past a critical point, nuclear forces give way and the nucleus separates. This is nuclear fission.

Nuclear Fission


Nuclear fission

  • The absorption of a neutron by a Uranium nucleus is enough to cause stretching.

Written as follows:


Nuclear fission

  • The combined mass of the fission fragments is less than the mass of the original Uranium atom.

    • The tiny amount of missing mass is converted into A LOT of energy.

    • One Uranium reaction releases about 200000000 e- volts. In comparison, the explosion of a TNT molecule releases 30 e- volts.


Nuclear fission

  • The scientific community was taken aback by the jaw-dropping intensity of nuclear fission reactions, as the amount of energy released and the number of neutrons liberated was extraordinary.

  • A typical fission reaction releases 2-3 neutrons, which will divide into 2-3 more nuclei, which will release 4-9 more neutrons, which will continue to divide further and further.

  • This is known as a chain reaction.

  • Naturally occurring U-238 does not chain react, as it isn’t refined enough. Only U-235 (only 0.7% of natural U) will go through fission.

-The minimum amount of mass required to sustain a chain reaction is called the critical mass.


Nuclear physics

Nuclear Physics

The Atomic Bomb

&

U-235 Separation


The manhattan engineer district

The Manhattan Engineer District

The Manhattan Project

A project designed to research and create a usable atomic bomb.

Now commonly called


Nuclear fission

1939- Albert Einstein along with several other physicists sent a letter to President Franklin D. Roosevelt.

It encouraged the research and development of an atomic bomb.

They feared the Germans had already embarked on such a course.

The result is what we now call the Manhattan Project.


Totals for the project

Totals for the Project

  • 40 laboratories and factories

  • Employed 200,000 people

  • Total cost: $ 1,889,604,000

  • Constant 1996 dollars: $ 21,570,821,000


Physicists struggle to determine how to spark a fission chain reaction

Physicists struggle to determine how to spark a fission chain reaction.


Their solution

Their Solution…

  • Drive 2 pieces of U-235 (each w/ less than the critical mass) together

  • If done correctly and at the right time, the combined mass will exceed the critical mass

  • Then a violent, chain reaction explosion will occur


U 235 separation

U-235 Separation…

The construction of a Uranium fission bomb is not a formidable task.

The difficulty is separating enough U-235 from the more abundant U-238.


Nuclear fission

Slightly lighter U-235 moves at a faster speed than U-238 at the same temperature.

As a gas, the faster isotope has a higher rate of diffusion through a thin membrane at the same temperature.

Results in slightly enriched U-235 gas on the other side of the membrane.


Nuclear fission

  • U-235 moves faster than U-238 because both have the same KE (1/2mv^2).

  • So, U-235 has a lower mass and thus a higher velocity.


Nuclear fission

It took Manhattan Project scientists and engineers more than two years to extract enough U-235 from uranium ore to make the bomb that was detonated over Hiroshima in 1945.

Uranium isotope separation is still a difficult, expensive process today.


Sources

Sources

  • Chapter Notes on Nuclear Physics Mr. Bobby

  • Conceptual Physics Third Edition Paul G. Hewitt

  • The Atomic Bomb Paper Natalie Bate (2000)

  • “Albert Einstein” Microsoft Encarta 96 Encyclopedia


Thanks

Thanks…

Concept, design, and creation by Natalie Bate and

Chris Geddes for 1st period Physics.

To everyone who paid attention.

Questions… comments… *smart remarks…

…see Natalie Bate or *Chris Geddes

5/15/02


Plutonium

Plutonium

  • When U-238 absorbs a neutron, no fission occurs.

  • Nucleus then emits a Beta particle and becomes Neptunium.

  • At Neptunium’s ½ life (2.3 days), another Beta particle is emitted and it becomes Plutonium.

  • The new isotope Pu-239 will undergo fission when it captures a neutron


Nuclear fission

  • The primary use of fermis atomic pile was to make Pu.

  • The development of Pu-239 solved the dilemma of separating U-235 out of U-238.

  • Pu will fission, and it’s much easier to obtain than U-235.

  • The bomb that exploded over Nagasaki was a Plutonium bomb.

  • Very dangerous due to radiation

  • Used on breeder reactors


Breeder reactors

Breeder Reactors

  • When U-238 is mixed with fissionable isotopes in a reactor, the neutrons released turn the abundant U238 into fissionable Pu-239

  • This in effect creates more fuel than it consumes

  • For every 2 fissionable isotopes put into the reactor => 3 fissionable isotopes are produced

  • Nuclear Reactors are simply nuclear furnaces, which boil H2O to produce electricity


Nuclear fission

plutonium

  • When U-238 absorbs a neutron, no fission occurs.

  • The nucleus then emits a beta particle & becomes neptunium.

  • At neptunium’s half life, (2.3 days) another beta particle is emitted & becomes plutonium.

  • The new isotope Pu-239 will undergo fission when it captures a neutron.

  • The primary use of Fermis atomic pile was to make Pu.

  • The development of Pu-239 solved the dilemma of separating U-235 out of U-238.

  • Pu will fission, & it’s much easier to obtain than U-235

  • Very dangerous due to radiation.

  • Used in breeder reactors.


Nuclear fission

Breeder Reactors

  • When U-238 is mixed with fissionable isotpes in a reactor, the neutrons released turn the abundant U-238into fissionable Pu-239.

  • This in effect creates more fuel than it consumes.

  • For every 2 fissionable isotopes put into the reactor, 3 new fissionable isotopes are produced.

  • Nuclear reactors are simply nuclear furnaces, which boil H2O produce electricity.


Fusion reaction can produce as much as 26 700 000 e volts

Nuclear Fusion

Fusion Reaction can produce as much as 26,700,000 e- Volts

Nuclear Fusion involves combining Hydrogen nuclei to form Helium

  • The mass lost in the fusion of Hydrogen

  • appears as energy


Nuclear fission

+

+

+

+

1

1

2

2

2

2

4

3

+

+

+

+

H H He n

H H He n

2

1

1

1

2

2

0

0

+

+

+

+

+

+

3.26 MeV

+

17.6 MeV

+

  • Nuclei must collide very quickly to overcome

  • electromagnetic repulsion of protons


Nuclear fission

Controlling Fusion

Tokamak

Fusion

Reactor


Nuclear fission

Tokamak Fusion Reactor

  • an experimental controlled fusion reactor

  • A donut-shaped fusion device that is

  • surrounded by electrical coils which produce

  • intense magnetic fields to confine hot, D-T

  • fuel plasma.


Nuclear fission

Frozen Deuterium Chamber

  • Deuterium is an isotope of Hydrogen that is

  • available in large quantities in seawater

  • Tritium is easily produced from deuterium


Nuclear fission

In inertial confinement fusion, deuterium and tritium

are liquefied under high pressure and confined in tiny

glass spheres. Multiple laser beams are directed at the

spheres. The energy deposited by the lasers results in

forces that make the pellets implode, squeezing their

contents. The tremendous compression of the hydrogen

that results raises the temperature to the levels needed

for fusion.


Nuclear fission

Cold Fusion

Meuon induced fusion

  • Meuon has the same charge as an e- but is

  • 200 times more massive

  • orbits very close to the nucleus

  • effectively cancels out electromagnetic

  • repulsion of protons

  • Only exists for 2 nanoseconds at a time

  • Would allow the nucleus to fuse at low

  • temperatures, for example a light bulb


Nuclear fission

Fusion Torch

of today

Raw Materials

Products

Consumers

Production Plants

Waste & Pollution

Non-fusion power


Nuclear fission

POLLUTION


Nuclear fission

  • White hot flame or plasma in which materials can be dumped

  • Plasma will break waste down to an atomic level

  • Atoms can then be separated using a mass spectrometer type device


Nuclear fission

the future...

Raw materials

Products

Fusion Power

Waste & Pollution

Fusion torch recycling plant


Boiling water reactors

Boiling Water Reactors

  • Water is boiled and turned to steam

  • Steam is used to rotate a turbine

  • The turbine powers a generator, which in turn creates electricity

  • Steam is recycled into water by a condenser


Nuclear fission

Boiling Water Reactor


Pressurized water reactors

Pressurized Water Reactors

  • Water is heated, but pressurized so that it doesn’t boil

  • Pressurized water flows through a different tank of water, boiling that water

  • Steam generated rotates a turbine, that powers a generator

  • Generator creates electricity

  • Steam sent through a condenser and recycled back into water to continue the process


Nuclear fission

Pressurized Water Reactor


  • Login