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Turning Rocks into Gold (Electric gold, that is)

Turning Rocks into Gold (Electric gold, that is). A miracle of modern alchemy Presented at Seminar on Canada’s Nuclear Technology University of Ontario institute of Technology October 15, 2009. Society. Potential Energy in the Universe. Hydrogen fusion (as well as other nuclei)

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Turning Rocks into Gold (Electric gold, that is)

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  1. Turning Rocks into Gold(Electric gold, that is) A miracle of modern alchemy Presented at Seminar on Canada’s Nuclear Technology University of Ontario institute of Technology October 15, 2009 Society

  2. Potential Energy in the Universe • Hydrogen fusion (as well as other nuclei) • in our sun and all visible stars • Uranium fission • both natural and man-made • Radioactive decay • energy from our primordial “big bang” via supernovae • Gravitation • drop a pencil, release some energy. Pick it up, store some energy (that energy came from the sun via your food) Environment

  3. Uranium? • It is radioactive • Uranium-238 decays by alpha particle emission to thorium-234; it eventually transforms into lead-206 • Uranium-238 also splits by spontaneous fission • 2 or 3 neutrons are released by the fission fragments • The fission and decay of natural uranium, thorium and potassium releases (in the whole earth) about 38 million megawatts • This radioactivity heats the core of the earth • geothermal energy leaving the earth’s surface comes almost entirely from this radioactive decay Science

  4. The First Fission Reactors(1.7 Billion years ago in Gabon, West Africa – 15 discovered) Uranium-Bearing Zone Water Steam Steam Steam Steam Water Cross section of Geological Strata Science

  5. Nuclear Fission E = mc2 • When two light nuclei fuse (join), mass is converted to energy • This happens in the sun • When a heavy nucleus fissions (splits), mass is converted to energy • This happens in a nuclear reactor • When gasoline burns, mass is converted to energy • This happens in your car’s engine Science

  6. What are some uses for Uranium? • We use heat from fission to make steam for a steam turbine • more than half Ontario’s electricity comes from uranium • We have used it to make nuclear bombs • and nations have formed a strong international organization (IAEA) to guard against use for weapons • We have used it to make attractive glass • until recently some glass-makers added uranium to glass. Such uses are now banned, to protect our health • We use it as ballast in B747 aircraft Technology, society and environment

  7. Energy of Fission • It could be called “Femtopower” a nucleus is very small • uranium nucleus diameter is 16 femtometers (10-15 meters) • It takes 31 billion fission reactions to release one watt-second (one joule) of energy. • Fission is sustained at a constant rate by neutrons emitted during earlier fissions, in a chain reaction • The fragments (fission products) are at first highly radioactive, then rapidly decay to stable elements • Most of the energy appears as heat in the fuel pellets. It is this energy that we use to boil water at high temperature and pressure Science

  8. Energy Flows Losses to environment Conduction Boiling Fission Potential Energy in the atomic nucleus Thermal energy (fuel) Thermal energy (water) Mechanical Energy (turbine) Induction Losses to environment Your lights, toaster, stove Electrical energy (generator) Technology, society and environment Transmission Engineering

  9. Nuclear Fuel(pellet) Thermal energy (fuel) • Uranium dioxide – ceramic, melting point 2800 C • It is slightly radioactive • One fuel pellet releases enough energy to make 2 slices of toast every minute for a year (about 1 million slices) • Over 6 million fuel pellets are loaded in each Darlington reactor, in 5760 fuel bundles • Darlington produces 3524 megawatts of electricity from 4 reactors • The world’s supply of nuclear fuel is inexhaustible Energy in the atomic nucleus Engineering Technology

  10. The Magnitude of the Hazard Varies Science, environment • Used fuel decays rapidly at first, then more slowly • The “last nucleus” does not decay for a very long time • Radioactive hazard returns to the original level after about 300 years About 7-8 orders of magnitude HAZARD OF NUCLEAR FUEL About 300 years USED FUEL COOLDOWN BEFORE LOADING REACTOR OPERATION

  11. Making Electricity Losses to environment • Heat energy is pumped in high pressure water to the boilers • Water is then boiled to produce steam to drive a steam turbine • Induction transforms mechanical energy into electrical energy • Electricity is transmitted to you, the customer, all within less than 30 seconds after fission • About 70% of the total fission energy is lost to the environment Thermal energy (water) Mechanical energy (turbine) Electrical energy (generator) Engineering

  12. Nuclear Reactor Designs • Most of today’s Nuclear Plants (436) use Water Reactors • Pressurized water reactor (PWR) • Boiling water reactor (BWR) • Pressurized heavy water reactor (PHWR) • These designs are being modified as technology improves • Under construction: 50 • On order or planned: 137 • Proposed: 295 • Future designs are known as “Generation 3 or 4” • Some of these power plants will use fast reactors (FBR) Society Engineering

  13. FBR CANDU CANDU A Canadian Dream for the FutureAround the year 2100? Society U REPROC. + FAB.PLANT FBR U/Th Pu Oxide Fabrication Plant Fresh Fuel Waste Fresh Fuel CANDU CANDU PWR BWR PHWR U238 U + Pu + f.p. Disposal Fission products CANDU Storage Reprocessing Plant DUPIC Plant

  14. Storing Electricity? – Transform It! Frequency Control Peak Tops Intermediate - reservoir limited Daily Energy Storage Intermediate Load Nuclear energy supply range Base Load Engineering

  15. Fuel -- A Small Part of Electricity Cost* • Today, the uranium price is about $90 per kilogram • At this price we have enough to fuel 6000 thermal reactors for > 40 years • As market price increases the amount of “ore” (at a lower grade) increases • The uranium fuel contribution to electricity cost is negligible today • If the uranium price were half the price of gold, the price of electricity from thermal reactors would double • If the uranium price were half the price of gold, it would be very profitable to extract uranium from seawater • Seawater is known to contain enough uranium to supply 100% of the world’s energy for 4000 years using thermal reactors (PWR, BWR, PHWR) or at least 600,000 years using fast reactors (FBR) • Thorium (another potential fuel) is more abundant than uranium in the earth’s crust Science * D.Lightfoot et al, “Nuclear Fission Energy is Inexhaustible”, Proceedings of the first Climate Change Technology Conference, Engineering Institute of Canada, Ottawa, May 2006

  16. It’s Not all Sweetness and Light • Fission must be controlled at a constant rate • High pressure pipes must hold water • Heat losses must not damage the environment • Radiation must be contained • Fission products (the ashes of fission) must be safely stored in the long term • Electricity must be affordable Technology • Today, we only use 1% of the energy in the fuel

  17. Nuclear Energy is: Available Safe Inexhaustible

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