Nuclear Energy ESCI 420 Spring 07 Nuclear Energy ESCI 420 Galen University Spring 2007

Nuclear Fission: breaking apart atom’s nucleus to produce huge amounts of energy Strong Force responsible for holding together protons and neutrons in a nucleus Fission breaks apart this binding energy Energy released is HUGE– 10 million times more than the energy released from the combustion of a carbon atom in coal Nuclear Fission

How it Works Fissile atomic nucleus (U-235 or Pu-239) is bombarded by neutrons to break it apart and produce smaller nuclei as fission products These neutrons then trigger further fusion, causing a controlled chain reaction Energy released from broken bonds can be used to heat water, producing steam, and then drive a turbine that generates electricity Water is usually used to moderate/cool reactors

Uranium Usage In naturally-occurring Uranium, about 0.7% is U-235 and around 99.3% is U-238 U-235 can be enriched to around 3%/97% U-235 is fissile, U-238 is not Current Light Water Reactors use up the U-235 and throw the rest away Huge amount of nuclear waste being produced from leftover U-238 material

Nuclear Reprocessing Nuclear Reprocessing Plants can recycle this nuclear waste to generate more energy U-238 is irradiated with neutrons, undergoes the reaction U n  Pu- 239 Pu-239 is a fissile material, so it can be re- used to create energy

Nuclear Reprocessing cont’d Nuclear Reprocessing can recycle up to 95% of the nuclear waste from the original fuel rods Reprocessing on a large scale is done in Britain, France, Russia, and Japan Dramatically reduces the amount of nuclear solid waste in nuclear plants

Concerns about Nuclear Reprocessing Reprocessing turns U-238 into useful Pu-239, which can be used to make nuclear weapons U.S. currently forbids reprocessing on the grounds of anti-proliferation

Nuclear Accidents Three Mile Island 1979 –Partial core meltdown –Worst accident in US commercial nuclear power generating history –Reactor was brought under control and radiation contained –Led to no deaths or injuries Chernobyl 1986 –Steam explosions caused nuclear meltdown, core of reactor is destroyed –Huge cloud of radioactive fallout drifted over parts of Western Soviet Union, Eastern and Western Europe, the UK, Ireland, and Eastern North America –Estimates range from 30-6,000 deaths and illnesses as a result of the accident –Many attribute accident to bad design of power plant

Other Nuclear Concerns Storage: Nuclear waste is currently contained and stored in plants, but running out of room –Yucca Mountain in Nevada – huge proposed nuclear waste storing repository about 90 miles from Las Vegas –Scheduled to be built in the next decade Costs: Significantly more expensive to build and maintain –Requires huge amount of initial capital –Expensive waste management issue Uranium mining: takes large amounts of energy to get usable uranium for reactors –Fossil-fuel intensive –Environmental justice issues

Proponents of Nuclear Power Emits fewer greenhouse gases –Only by-product from plants is steam Produces large amounts of electricity with less pollution than coal-powered plants –Reprocessing would potentially lower this pollution amount significantly Abundant Supply –Uranium is relatively common –Supplies are estimated to last for hundreds to thousands of years

Is Nuclear Feasible? Political ramifications Public opinion Research & Development Initial investment