Are you prepared?... start 2:27

Renewable or Non-Renewable?

Uranium 92 U C Carbon How many protons? How many electrons? How many neutrons? 92 protons 92 electrons 146 neutrons What is Radiation?

Radiation = particles given off by unstable atoms. 3 Types: –Alpha ( α) Travels few inches Blocked by paper (skin) –Beta ( β) Travels few feet Blocked by aluminum, glass –Gamma ( γ) Travels far Blocked by lead (steel & concrete).

Background Radiation The amount of radiation we are exposed to daily from the environment Average = 360 millirem/year or 3 millisieverts

EVR3019/Nuclear_Waste.ppt

Genetic damages: from mutations that alter genes defects can become apparent in the next generation Somatic damages: to tissue, such as burns, miscarriages & cancers Effects of Radiation t

Nuclear waste Power plants produce radioactive wastes –mostly spent fuel rods (3-4 years) –each reactor produces about tons yearly Currently stored in pools on site and then above ground casks –some remain dangerous for tens of thousands of years How should we store this waste?

Yucca Mountain

Options for Waste –Keep onsight –Bury –Shoot into space –Bury in ocean floor –Bury in Antarctica –Change it into harmless or reprocess to make new fuel

Low-Level & High Level Radioactive Waste Emit small amounts of ionizing radiation Stored years 1940  1970: put in steel drums, dumped in ocean (still UK & Pakistan) 1970+: gov’t run landfills Stored for thousands of years Mostly spent fuel rods (240,000 yrs) Safety debate Options: –Keep onsight –Bury –Shoot into space –Bury in ocean floor –Bury in Antarctica –Change it into harmless

Nuclear Energy The energy that exists within the nucleus of an atom. Nuclear Fission = the release of energy from the splitting of atoms! Nuclear Fusion = the combining of two smaller atoms into one larger atom.

Nuclear Fission

Nuclear Fusion

Nulear Change Nuclear Fission Bombs & power plants Big, unstable isotopes are struck by neutrons, which splits the isotope’s nuclei More neutrons “shoot out” to strike nearby isotopes, causing a chain reaction. Nuclear Fusion Sun and stars, some weapons 2 small (light) isotopes are forced together –H + H = He Need temps > 100,000,000 º C Releases more E than fission

437 commercial reactors in 32 countries, producing 17% electricity

Nuclear Power Plant 1.a controlled nuclear fission chain reaction 2.heats water 3.produce high-pressure steam 4.that turns turbines 5.which turns generator and creates electricity.

Controlled Nuclear Fission Reaction

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Boiling Water Reactor

Pressurized Water Reactor Boiling Water Reactor

Nuclear Reactor Where nuclear fission occurs. Surrounded by thick concrete, steel & lead. Blocks all radiation!

Inside the Reactor Fuel Rods –35,000 – 70,000 fuel rods –3% Uranium-235 pellets –In water (moderator) Control Rods –absorb extra neutrons –Control the chain reaction html#project%3DFUELASSEMBLY0317%26articleTabs%3Dinteractive

Cooling Tower Water is the coolant in the system. Tower is used to condense hot steam to liquid water. Usually taken from river, lake, ocean. Water can be reused.

Decommissioning Life span of a power plant = years –Parts wear out, Fuel is spent –Plant is shut down Highly radioactive for 240,000 years Must store for 10 times the half-life –What can we do with them?

= time needed for one-half of the nuclei in a radioisotope to decay and emit their radiation to form a stable isotope Half-timeemitted Uranium million yrsalpha, gamma Plutonium 23924,000 yrsalpha, gamma Half-Life t

When people think about nuclear power they think about… 1.Effects of radiation 2.Nuclear waste disposal 3.Nuclear disasters

Three Mile Island sieverts over 7 days Remember 1,000 sieverts is radiation sickness 5,000 is death %20map&ndsp=20&safe=on&ie=UTF-8&sa=N&tab=il

Chernobyl sieverts per hour 240 acute radiation sickness; 31 died within 3 months 100,000 people evacuated Some claim up to 985,000 deaths due to Chernobyl

Chernobyl Fallout

Japan 0.4 sieverts per hour 70,000 people evacuated 140,000 told to stay inside

earch/assetDetail.cfm?guidAssetID=BE0F B49C-7C70-4C56-95F2-B3904BC9077Fhttp://streaming.discoveryeducation.com/s earch/assetDetail.cfm?guidAssetID=BE0F B49C-7C70-4C56-95F2-B3904BC9077F 10 min video on nuclear energy –Fission, fusion, overview