APES 6.6 & 6

Nuclear fission

A process where a neutron hits the nucleus of a radioactive element causing it to break apart and release energy.

Radioactivity

The energy emitted from the nucleus of a radioactive isotope during its decay process.

Radioactive half-life

The time required for half of a radioactive substance to decay.

Components of a Nuclear energy machine

Control rods, water pump, cooling tower.

Role of control rods

They absorb neutrons to slow down the nuclear reaction and prevent meltdown.

Role of water pump

Brings in cool water to be heated into steam and cools the reactor.

Role of cooling tower

Helps condense steam back into water and cool before reuse.

Greenhouse gases from Nuclear energy

Primarily released during the mining of uranium and construction of power plants.

Gas released from Nuclear electricity generation

Water vapor, which can be considered a greenhouse gas.

Drawbacks of Nuclear energy

Spent fuel rods, mine tailings, water use, thermal pollution.

Spent fuel rods

Used fuel rods that remain radioactive for millions of years.

Mine tailings

Waste materials from mining that may contaminate nearby water and soil.

Water use in Nuclear energy

Nuclear plants need significant amounts of water, risking depletion of local sources.

Thermal pollution in Nuclear energy

Release of hot water into surface waters causing thermal shock.

Three significant Nuclear meltdowns

Three Mile Island, Fukushima, Chernobyl.

Three Mile Island

Partial meltdown in 1979 with no deaths or residual cancer cases.

Fukushima

Meltdown triggered by an earthquake and tsunami in 2011 resulting in widespread radiation.

Chernobyl

Complete meltdown in 1986 due to a stuck cooling valve, causing several deaths.

Environmental consequences of meltdowns

Genetic mutations and cancer in people, animals, and plants due to radiation.

Biomass

Organic materials burned for heat in heating homes or cooking.

Biofuels

Liquid fuels made from biomass used as alternatives to gasoline.

Carbon difference in biomass vs. fossil fuels

Biomass burning does not increase atmospheric CO2 levels; fossil fuels do.

Human health consequences of biomass burning

Releases irritants leading to respiratory issues like asthma and COPD.

Environmental consequences of biomass burning

Deforestation and air pollutants leading to smog.

How biofuel ethanol is formed

Corn or sugar cane is fermented by yeast to create ethanol.

E85/Flex-fuel

A mix of 51-83% ethanol with gasoline used in flex fuel vehicles.

Environmental consequences of ethanol production

Negative impacts from monocropping including soil erosion and habitat loss.

Sustainable ethanol production

Using algae or waste oils for fermentation rather than crops.

Biodiesel

Liquid fuels made from specific plant oils and found to emit GHGs.

Sustainable biodiesel production

Using cleared lands or practices to replant crops to reduce environmental impact.