CURRENT USE STATISTICS HISTORY OF NUCLEAR ENERGY NUCLEAR POWER CYCLE Basics of Nuclear Power

History Ernest Rutherford – split the atom in 1917 Enrico Fermi – nuclear fission in 1934 Scientists realized fission reactions could be self- sustaining First man-made reactor – Chicago Pile-1 in 1943 (later part of the Manhattan Project) Stricter government regulation after WWII Movement against nuclear power driven by fear and history of nuclear accidents

Current use statistics Worldwide - 2.1% of the energy and 15% of electricity United States, France, and Japan 56.5% of nuclear- generated electricity Economics – large initial investment ($6-10 billion), most economical to run plants for as long as possible or add reactors to existing plants From the 2003 MIT study, “The Future of Nuclear Power”:  “In deregulated markets, nuclear power is not now cost competitive with coal and natural gas. However, plausible reductions by industry in capital cost, operation and maintenance costs, and construction time could reduce the gap. Carbon emission credits, if enacted by government, can give nuclear power a cost advantage.”

Nuclear fuel cycle

Exploration Two uranium isotopes U-235 (0.71%) and U-238 (99.29%) U-235 is a fissile isotope – fissions when hit by a free neutron U-238 absorbs the free neutron to become U-239 U-238 become Pu-239, a fissile isotope, though natural radioactive decay

Uranium mining and processing Open-pit (surface), underground, and in situ leaching mining techniques Uranium ore in the United States ranges from 0.05% to 0.3% uranium oxide (U 3 O 8 ) Trace quantities of uranium in domestic phosphate- bearing deposits of marine origin Uranium ore is ground and the uranium is extracted though chemical leaching The resulting product, yellowcake, is sold as uranium oxide

Uranium ore Yellowcake Uranium mining and processing

Uranium conversion Uranium oxide converted to uranium hexaflouride, form required by most commercial uranium enrichment plants  Solid at room temperature, gas at 57°C  Conversion of only natural uranium (not enriched)  Most uranium converted to UF 6 Also convert to uranium dioxide (UO 2 ) for reactors that do not require enriched uranium

Enrichment Natural UF 6 enriched to fissionable isotope Light-water reactor fuel enriched to 3.5% U-235 Various methods of isotope separation – gaseous diffusion, gas centrifuge 96% of byproduct is depleted uranium 95% of DU is stored as uranium hexaflouride

Fabrication Enriched UF 6 converted into UO 2 powder, which is processed into pellets Pellets fired in sintering furnace, processed to be uniformly shaped Pellets stacked into tubes of metal alloy and sealed, creating fuel rods (specific to reactor core) For BWR and PWR, fuel rods bundled, given unique identification numbers (trace from manufacture to disposal)

Transportation Most transports of nuclear fuel material occur between different stages of the cycle Minimize radiation exposure Special handling for spent fuel and high-level waste Spent nuclear fuel shipping casks, shielding techniques

In-core fuel management and interim storage Array of cells, each cell is fuel rod surrounded by coolant (water) Water or boric acid provide cooling (decay heat from residual radioactive decay) and shielding After operating cycle, spent fuel discharged and usually stored in spent fuel pool When spent fuel pool is filled, store cool aged fuel in dry storage facility (ISFSI)

Reprocessing Fissile and fertile materials, such as U-235, Pu-239, and U-238, can be chemically separated and recovered from the spent fuel to be recycled for use as nuclear fuel Mixed oxide fuel (MOX) – blend of reprocessed uranium, plutonium, and depleted uranium; behaves similarly to the enriched uranium  Alternative to low-grade uranium used by light-water reactors

Waste disposal “the Achilles heel of the nuclear industry” Disposal of spent fuel and disposal of wastes from processing plants Nuclear Waste Policy Act (1982) – Department of Energy responsible for waste disposal system for spent nuclear fuel and high-level radioactive waste Deep geological repository for solid wastes, burning High-level radioactive waste – spent fuel (spent fuel pools  casks)  Proposed storage at Yucca Mountain, no longer harmful after 10,000 years (EPA) Low-level radioactive waste – contaminated items, hand tools, water purifier resins, and the reactor materials

Three Mile Island Accident March 28, 1979 Combination of equipment failure and confused plant operators. Partial melting of fuel rod cladding. Release of 43,000 curies of radiation released Very strong containment shell built over reactor thanks to activists No deaths or injuries-exposure to people in a 10 mile radius was about the same as receiving a chest x-ray Lots of unknowns and fear at the time of the accident

Chernobyl April 26, 1986 Ukranian republic of the USSR Monitoring turbine generators during at low power Reactor design made it unstable at low power and operators didn’t take proper safety precautions A power surge caused two explosions which destroyed the reactor core and blasted a hole in the roof of the reactor building million curies released into atmosphere radioactivity estimated to be about two hundred times that of the combined releases in the bombing of Hiroshima and Nagasaki Evacuation zone of ~1,100 square miles Over 75,000 people relocated Fallout devastated farmland, increased rates of thyroid cancer in children Possibility of birth defects in future generations Plant completely shut down in 2000

Nuclear Proliferation Plutonium is a waste product of nuclear fission- this can be used as further fuel or to make nuclear bombs International Atomic Energy Agency (IAEA)- responsible for monitoring the world’s nuclear facilities and preventing nuclear proliferation. The agency has acknowledges that there is a large amount of uncertainties and its impossible to detect all diversions of nuclear material.

Hanford Nuclear weapons production beginning in 1943 Built along the Columbia river Released large amount of waste into river/air Affected 75,000 square miles

Hanford continued Secrecy surrounded the operation Increased citizen pressure finally allowed for release of 19,000 page document regarding Hanford’s history Between approximately 2 million people exposed Doses of I-131 increases risk of thyroid cancer, children most susceptible Currently Hanford is the most contaminated nuclear waste site in the U.S. and focus of largest environmental cleanup 53 million gallons of high level radioactive waste = 2/3 of nations high-level radioactive waste by volume Hard to find data correlating cancer and exposure

High Level Radioactive Waste

Shearon Harris New Hill, NC in Wake County Single Reactor Until 2003 nuclear waste from two other plants were being shipped in for temporary storage on trains Currently houses nation’s largest spent fuel pools. These rods are packed in high density-run the risk of going critical

Long Term Storage at Yucca Mountain 90 Miles northwest of Las Vegas 33 known geological faults in the vicinity earthquake 8 mile from site center which damaged DOE project office Storage to be well above water table but DOE underestimated the time for water to seep from the surface The earliest Yucca Mountain could open would be 2017 and by this point the amount of commercial waste produced will have surpassed the legal limit allowed in Yucca Mountain…a second repository would be needed

Yucca Mountain

“Low-level” Radioactive Waste Very poor classification Example: Includes medical waste as well leakages from the reactor core Most medical waste is hazardous for less than 8 months but reactor waste in the same category could be hazardous for hundreds of thousands of years Trend has been to downgrade high grade waste. Saves money as regulations only require 100 years of passive institutional control. NRC has planned for allowed/acceptable leakages (life on container does not last radioactivity lifespan) which are deemed as acceptable risks