6.6 Nuclear Energy

Nuclear fission & radioactivity

A neutron is fired into nucleus of a radioactive element (like uranium)

Radioactive: energy given off by the nucleus of a radioactive isotope (uranium-235)

Radioactive half-life: amount of time it takes for 50% radioactive substance to decay

Generating electricity

Same electricity generation process as with fossil fuels

Heat → water into steam → steam to a turbine → turbine powers generator → generator produces electricity

Uranium-235

Stored in fuel rods, submerged in water in reaction core; heat from fission turn H20 to steam

3 parts to generating electricity

Control rods: lowered into reactor core to absorb neutrons & slow reaction, preventing meltdown (explosion)

Water pump: brings water to turn to team & cools reactor down from overheating

Cooling tower: allows steam from turbine to condense to liquid & cool down before being reused (gives off H20 vapor)

Nonrenewable, but cleaner than fossil fuels

Nuclear energy Nonrenewable: because elements like uranium are limited

Other drawback or nuclear energy include possible meltdown & radioactive contamination

Spent fuel rods: used fuel rods, radioactive for millions of years & stored in lead containers on site at nuclear power plants

Mine tailings: leftover rock & soil from mining, may have radioactive elements → contaminate water

Water use: nuclear power plants require water & can deplete local surface/ groundwater sources

Thermal pollution: hot water from power plants released back to surface waters → thermal shock

Nuclear meltdowns

3 most famous nuclear meltdowns…

Three Mike Island (US): partial meltdown → testing error (radiation released, no deaths)

Fukushima (Japan): earthquake & tsunami triggered cooling pump failure → meltdown & radiation

Chernobyl (Ukraine): stuck cooling valve during test → complete meltdown, deaths, radiation

Environmental consequences of meltdowns

Genetic mutations & cancer with people, animals, & plants due to radiation from reactor core

-contaminated soil (radiation in soil → harm plants/ animals → genetic mutation)

-radiation spread (carried by wind)