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Spent Fuel Revisited

Spent Fuel Revisited

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Spent Fuel Revisited

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    1. Spent Fuel Revisited Tad Cleaves Energy Law April 26, 2006

    2. Overview World Demand for Electricity is Growing Nuclear Energy & Fuel Cycle Safety Environment Conclusions

    3. Demand for Electricity is Growing Rapidly Electricity Consumption will almost double in next two decades. Industrialization Population Expansion

    4. Demand For Energy Growing Oil Up 50% Coal Up 57% Natural Gas Up 140%

    5. Fossil Fuels are Kings of Electricity Fossil Fuel: ~66% Nuclear: ~17% Hydro: ~17% Other: ~2% (2001) (2001)

    6. Fuel Supplies are Dwindling Inexpensive Petroleum Supply measured in terms of decades Natural Gas measured in decades to maybe a century Coal measured in centuries Inexpensive Uranium deposits measured in decades to maybe a century

    7. More Efficient Nuclear Fuel Cycle Extend Present Reserves Lower Carbon Emissions

    8. General Information ~20 % of U.S. electrical generation 50 % of Illinois electrical generation Same principles as coal or natural gas plants 103 U.S. nuclear power plants 440 global power plants All but 2 are Thermal Light Water Reactors

    9. Nuclear Fuel Thermal Pressurized Water Reactors are most common type of reactor Start with enriched uranium In nature: 99.3% U238 Fissionable and Fertile .7% U235 Fissile Enriched Uranium: ~5% U235 Pu239 by-product of neutron absorption. Fissile

    10. Source of Heat: A Possible Reaction in a Reactor n + 235U ??141Ba + 92Kr + 3n Masses: U = 235.043 924u Ba = 140.909 241 Kr = 91.905 038 n = 1.008 665 236.053u ? 235.84u

    11. Mass Difference = ?E 236.053u ? 235.84u is a mass difference of 0.2123u E = mc2 ?E = 0.2123 x c2 Yields ~ 197.757 MeV energy Per atom, this is about 5,000,000 times!! the energy released in combustion of oxygen.

    12. The Goal: Controlled Chain Reaction

    13. Two Chain Reactions...

    14. Spent Fuel: Radioactive Waste 3 Classes of Waste Material Fission Products (5%) Mostly Cesium 137 and Strontium 90 Dangerous ~300 years Uranium 238 (~94%) Transuranics (1%) Everything heavier than Uranium Dangerous, long-lived isotopes. 10,000+ year half-lives

    15. Transuranics

    16. Once-Through Fuel Cycle All of this material is considered waste Inefficient: Only 5% of potentially fissionable atoms have been used!! Only 10% of mined uranium is converted into fuel in enrichment process. Bottom Line: Less that 1% of the ores total energy is used to generate energy in once-through regime! Spent fuel Still contains 95% of its original energy.Spent fuel Still contains 95% of its original energy.

    17. This Waste Can Still Power Reactors Needs to be Reprocessed First France, Japan, Russia, and UK reprocess Jimmy Carter banned civilian reprocessing in US in 1977 Fear of weapons-grade Pu239 proliferation Two types of reprocessing: PUREX and Pyro

    18. PUREX Plutonium URanium Extraction Devised for weapons manufacture Synonymous with reprocessing when reprocessing was banned in 1970s Extracts pure Pu239 from spent fuel Pu239 is the isotope of Pu used for atomic weapons

    19. PUREX for Electricity Pu239 is used to power reactors in the form of metal oxides (MOX). Can be burned in thermal reactors Total Energy Usage: 6% of original reactor fuel energy is used 94% still unharnessed Massive amounts of waste left over.

    20. The Pyrometallurgical Process Pyro collects virtually all of the transuranics and much of the uranium Few transuranics in the final waste stream Pure Pu239 is never isolated Based on electroplating Combination of transuranics with fission products makes this waste unsuited for weapons or thermal reactors. Combination of transuranics with fission products makes this waste unsuited for weapons or thermal reactors.

    21. Problems with Pyro Basic principles have been demonstrated, but the technology is not ready for immediate commercial use. The fuel extracted can be burned in Fast Reactors only. NOT usable in Thermal Light Water Reactors Only 2 Fast Reactors operating in the world

    22. Fast Refers to Neutron Speed Light Water Reactors take advantage of Slow, thermal neutrons These neutrons can easily split unstable, fissile atoms: Pu239, U235 Sometimes split other atoms: U238 High capture cross section Fast Neutrons Have higher fission cross section Can split all actinides

    23. Fission vs. Capture in PWR and Fast Reactor

    24. Fast Reactor Designs Loop design is the older design. Pool design can use heat convection if active cooling fails. Safer design.Loop design is the older design. Pool design can use heat convection if active cooling fails. Safer design.

    25. Energy Efficiency of Fast Reactors Can recover 99% of energy in spent thermal reactor fuel After thermal reactor fuel runs out, Fast reactors can burn depleted uranium. Depleted = Non-enriched U238 99% energy recovery MUCH GREATER YIELD

    26. Fast Reactors In Operation Not a new technology Los Alamos, NM, 1946 Naval Applications Especially Soviet US, France, Russia, and Japan have built FRs India is pursuing FRs Only 2 in civilian operation France & Russia Phenix in France for experimentation and transmutation of nuclear waste BN-350 built by Soviets on Caspian Sea. Also produces 80,000 gallons of fresh water per day. Phenix in France for experimentation and transmutation of nuclear waste BN-350 built by Soviets on Caspian Sea. Also produces 80,000 gallons of fresh water per day.

    27. Why are FRs not in use? Reprocessing is a bad word. Out-dated bias Pyro process also untested commercially No infrastructure at this point Uranium is inexpensive Fuel is not significant portion of cost ~5% of total cost of nuclear generation is fuel Compared to ~75%-80% of cost of natural gas generation. Easier keep loading the proven thermal reactors with cheap uranium

    28. Greater Safety Issues? No Safer than light water reactors Operate at atmospheric pressure Use liquid metal coolant instead of water Have more passive safety features Strong track record The problems encountered (e.g. Monju, Japan) have resulted in little more than big messes No radiation released.

    29. No Plutonium Proliferation Fast Reactors efficiently consume plutonium. Light Water reactors are plutonium breeders The only waste products are the fission products Nuclear Ash No Plutonium Mines

    30. Bad Presentation TimingChernobyl Disaster 20 Years Ago, TODAY! Cause Unauthorized testing that caused the reactor to lose control Reactor lost control Effect Steam explosion blew the top containment off the reactor core Large contamination release across a 20 square mile area LIFE: 48 deaths directly Shady records Thousand exposed to elevated radiation

    31. Other Energy Related Accidents China Coal Mining Industry (11/05) Qitahe, China: 171 workers were killed 5,491 coal workers deaths in 2005 Unofficial statistics closer to 20,000 deaths 2,900 reported accidents

    32. Environmentally Superior Emission free The only waste produced by FRs with this fuel cycle is nuclear ash. 1,000 MWe FR would produce 1 ton of fission products. (1% the waste of light water reactor) Only very small amounts of long-lived transuranics FRs can burn the 30+ years-worth of stored spent fuel. No need for long-term storage (Yucca Mountain)

    33. Environmental Cost of Hydro

    34. Conclusions Need more research Pyro and FRs in large-scale production Several Decades Required Huge upside Produce electricity indefinitely Transmutate nuclear waste Price Stability Environmentally sound

    35. For more information: Decide the Nuclear Issues for Yourself Nuclear need not be Unclear by J.A.L Robertson The New Economics of Nuclear Power, World Nuclear Association, The Path to Sustainable Nuclear Energy Basic and Applied Research Opportunities for Advanced Fuel Cycles, 2005, Smarter Use of Nuclear Waste by William Hannum

    36. Questions??