370 likes | 704 Views
5% of total cost of nuclear generation is fuel. Compared to ~75%-80% of cost of natural gas generation. ... The only waste produced by FRs with this fuel cycle is nuclear ash. ...
E N D
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% http://www.imf.org/external/pubs/ft/fandd/2003/03/okog.htmhttp://www.imf.org/external/pubs/ft/fandd/2003/03/okog.htm
5. Fossil Fuels are Kings of Electricity Fossil Fuel: ~66%
Nuclear: ~17%
Hydro: ~17%
Other: ~2% http://www.centreforenergy.com/images/tn-fuelshares.gif (2001)http://www.centreforenergy.com/images/tn-fuelshares.gif (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… http://www-fusion-magnetique.cea.fr/gb/energies/ere_petrol_gb.gif
http://www.niauk.org/nuclear_alternative.shtmlhttp://www-fusion-magnetique.cea.fr/gb/energies/ere_petrol_gb.gif
http://www.niauk.org/nuclear_alternative.shtml
7. More Efficient Nuclear Fuel Cycle Extend Present Reserves
Lower Carbon Emissions http://www.mcps.k12.md.us/schools/stonegatees/EdLinks/images/atom.gifhttp://www.mcps.k12.md.us/schools/stonegatees/EdLinks/images/atom.gif
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... http://hem.passagen.se/crow1980/atom.jpghttp://hem.passagen.se/crow1980/atom.jpg
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 ore’s 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 http://en.wikipedia.org/wiki/Fast_reactor
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.http://en.wikipedia.org/wiki/Fast_reactor
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 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 http://en.wikipedia.org/wiki/Coal_mining#Dangers_to_minershttp://en.wikipedia.org/wiki/Coal_mining#Dangers_to_miners
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 http://www.magma.ca/~jalrober/Decide.htm
The New Economics of Nuclear Power, World Nuclear Association, 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.energy.gov/engine/content.do?BT_CODE=NUCLEAR
Smarter Use of Nuclear Waste by William Hannum
36. Questions??