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

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Presentation on theme: "Spent Fuel Revisited Tad Cleaves Energy Law April 26, 2006."— Presentation transcript:

1 Spent Fuel Revisited Tad Cleaves thollandc@hotmail.com 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%

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% U 238 “Fissionable” and “Fertile” .7% U 235 “Fissile” Enriched Uranium:  ~5% U 235 Pu 239 by-product of neutron absorption. “Fissile”

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

11 11 Mass Difference =  E 236.053u  235.84u is a mass difference of 0.2123u E = mc 2  E = 0.2123 x c 2 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... Controlled Chain Reaction: Electricity Uncontrolled Chain Reaction: Bad News…

14 Spent Fuel: Radioactive “Waste” 3 Classes of “Waste” Material 1. Fission Products (5%) – Mostly Cesium 137 and Strontium 90 – Dangerous ~300 years 2. Uranium 238 (~94%) 3. 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 ore’s total energy is used to generate energy in once-through regime!

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 Pu 239 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 Pu 239 from spent fuel  Pu 239 is the isotope of Pu used for atomic weapons

19 PUREX for Electricity Pu 239 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 Pu 239 is never isolated Based on electroplating

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: Pu 239, U 235  Sometimes split other atoms: U 238  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

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 U 238  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

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 Timing… Chernobyl 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 Before & After: Grand Coulee Dam Everything has a price...

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 http://www.magma.ca/~jalrober/Decide.htm http://www.magma.ca/~jalrober/Decide.htm The New Economics of Nuclear Power, World Nuclear Association, http://www.uic.com.au/neweconomics.pdf http://www.uic.com.au/neweconomics.pdf The Path to Sustainable Nuclear Energy Basic and Applied Research Opportunities for Advanced Fuel Cycles, 2005, http://www.sc.doe.gov/bes/reports/files/PSNE_rpt.pdf http://www.sc.doe.gov/bes/reports/files/PSNE_rpt.pdf http://www.energy.gov/engine/content.do?BT_CODE=NUCLEAR Smarter Use of Nuclear Waste by William Hannum

36 Questions??


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