Nuclear fusion

1. Nuclear fusion • Source of Sun’s energy • Hydrogen nuclei (deuterium (extra neutron) and tritium (2 extra neutrons)) fuse together to produce energy along with helium and a neutron • Einstein’s equation • E=mc2 • Occurs at extremely high temperatures and pressures • Inexhaustible source of hydrogen found in the world’s oceans (water H2O)

2. Nuclear fusion • First studies by Earnest Rutherford in 1934 • Very well understood • Produces high speed neutrons and helium • Detection of neutrons is test of whether fusion takes place • Technology of hydrogen bomb

3. How to cause fusion • Create a high temperature plasma • Plasma: atoms without electrons • Problem: In the Sun gas expansion is prevented by gravity. There is no container on earth to prevent the expansion without it melting • Possible solution: Using a magnetic field to contain gas but it needs too much energy to produce it. • Magnetic field: possible solution in the future-Princeton Plasma Physics Laboratory is working on it • Developed tokamak: used for magnetic confinement. • June 6, 2006 • AT A ceremony in Brussels last week, governments representing more than half the world's population - from China, the European Union, India, Japan and the US, among others - signed up to spend about $5 billion to build ITER, the world's largest nuclear fusion machine. It should be the first fusion machine to deliver more energy than it consumes, and the optimists heading the programme say it will turn fusion power into a major energy source by mid-century.

4. MIT Fusion Research

5. Nuclear Fission • Current technology for generating nuclear energy • Nuclear fission: splitting of the nucleus http://science.howstuffworks.com/nuclear-power2.htm • Technology of atom bomb • Must have a critical mass of enriched uranium to obtain a chain reaction

6. Nuclear Fission www.atomicarchive.com/Fission/www.atomicarchive.com/Fission/Images/fission.jpgs/fission.jpg

7. Nuclear Reactor http://www.daviddarling.info/images/nuclear_reactor.jpg • Fuel rods: enriched uranium- uranium-235) • Control rods: Boron absorbs neutrons • Moderator: slows down neutrons (water)

8. Nuclear Reactor http://oncor.com/images/knowledgecollege/h20.jpg

9. Cold Fusion and the Utah Chemists • New scientific findings • Scientific conference • Scientific journal • Anonymous experts are chosen to review the work • If no errors are found, work is published • Cold fusion: did not go through the scientific review process • March 23, 1989: Martin Fleischmann and Stanley Pons hold a PRESS CONFERENCE stating that they have found a limitless source of clean energy: cold fusion

10. Cold fusion • Story appeared in • Financial Times • Wall Street Journal • Almost every other major news organization • White House believed it • Exxon’s supertanker Valdez spilled all its oil on Bligh’s Reef in Alaska’s Prince William Sound • Gave the news of cold fusion more urgency • Other scientists were skeptical • “Extraordinary claims are expected to be backed up by extraordinary evidence” Carl Sagan, astronomer • No important details were given in press conference to allow other scientists to test cold fusion

11. Problems with cold fusion perceived by other scientists • Fleischmann and Pons didn’t seem aware that other scientist knew about high concentration of hydrogen in metals • The tests of Fleischmann and Pons should have produced lethal doses of nuclear radiation • Joke among their colleagues “Have you heard the bad news about the research assistant in Pons’ lab? He’s in perfect health.” • Number of neutrons claimed to be seen was 1 million times too small • When experiment was finally published on all its details, all physicists replicated with the same results: No fusion occurred • Scientists were interested though. Why? • They smelled blood.