Nuclear Fusion: The Future of Nuclear Power

Sarah Hobart, Jenny Hoekstra, and Greg Stewart

Definitions

Nuclear Fission-the process of using a neutron to split a heavy nucleus into two nuclei with smaller masses Nuclear Fusion-the process of combining two light nuclei to form a heavier, more stable nucleus

Possible Nuclear Fusion Reactants

Magnet used in Nuclear Fusion Experiments http://web.mit.edu/newsoffice/tt/2002/sep25/magnet.jpg

Fusion Energy Release

1 H + 1 n  2 H +   Mass Difference is 0.002388 amu  Energy Release is equal to: (0.002388)(931.5 MeV/amu) = 2.22 MeV/atom H  This is equivalent to 2.14 X10 11 Hydrogen J/mol of  There is no harmful byproduct to this reaction

Visualization

http://science.howstuffworks.com/nucle ar-bomb1.htm

Fusion Energy Release

1 kg of hydrogen could run a 60 W light bulb for about 112,000 years.

 (1kg) x (1000g/kg) x (mol/1.008g) x (2.14x10

11 J/mol) =

2.12x10

14 Joules

x (s/60J) = 112,000 years

Requirements for Nuclear Fusion

Nuclei must be at a very small distance to combine (~10 -13 cm)  This is achieved by shooting the atoms at each other at very high velocities.

Fusion is possible as long as the final product has more binding energy (less mass) than the reactants

Electrostatic Force

Must overcome very high electrostatic forces to get nuclei close enough.

F=Kq 1 q 2 /r 2 =(9X10 9 )(1.6X10

-19 C)(1.6X10

-19 C)/(10 -15 m) 2 F=230.4 N

Methods of Nuclear Fusion

Thermonuclear devices  Heat particles to 4 X10 7 K in order to accelerate particles to high speeds Fusion Bomb  Energy from a fission bomb can be used to ignite a fusion bomb (T=2-4X10 8 )

Advantages and Disadvantages of Fusion

Hydrogen and tritium could be used as a fuel source Higher energy output per unit mass than fission Low radiation levels associated with process than fission-based reactors Breakeven point has not been reached after ~40 years of expensive research and commercially available plants not expected for at least 35 years

The Sun Using Nuclear Fusion

Energy output of millions of eV per reaction is needed if the Sun has been producing energy at the observed rate over billions of years 26 MeV is released each time the reaction occurs – 685 million tons of mass converted to energy each second It takes a photon 100,000 to 200,000 years to reach the surface

Sources

Giancoli, Douglas C. Physics: Principle with Applications. 5 th Edition. New Jersey: Prentice Hall, 1998. p. 953-55.

Zumdahl, Steven Z. Chemical Principles. 3 rd Edition. Boston: Houghton Mifflin Company. 1998. p. 960-62.

http://web.mit.edu/newsoffice/tt/2002/sep25/magnet.j

pg http://www.nucleartourist.com/basics/why.htm

http://www.ucolick.org/~bolte/AY4/notes7/node4.html

http://zebu.uoregon.edu/~soper/Sun/fusion.html

http://science.howstuffworks.com/sun2.htm

http://www.cottonexpressions.com/images/sunsml.jpg

Questions??

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