Please enable JavaScript.
Coggle requires JavaScript to display documents.
7.3 nonrenewable energy- nuclear sources (nuclear meltdown (a coolant,…
7.3 nonrenewable energy- nuclear sources
nuclear sources
nuclear power plant= a highly complex + costly system designed to perfomr a relativiley simple task: boil water to produce steam that spins a turbine and generates electricity
creates heat controlled by nuclear fission reaction
nuclei of certain isotopes with large mass numbers are struck by a neutron. it splits the heavy nuclei apart into lighter nuclei and releases energy.
this fission releases neutrons which cause more nuclei to fission. this results in a chain reaction that releases a big amount of heat energy in a short time
reaction takes place in the core of a reactor
nuclear fuel
the fuel for a nuclear reactor is made from uranium ore which is mined from the earths crust.
uranium is common in rocks and sea water
enrichment: only 1% of uranium-235 is fissionable
the enriched uranium-235 is processed into small pellets of uranium dioxide. each pellet is the size of a pencil eraser and contains the amount of energy = to a ton of coal
the nuclear fuel cycle
building a nuclear power plant,
mining the uranium
processing and enriching the uranium to make fuel
using it in a reactor
safely storing the resulting highly radioactive wastes for thousands of years until their radioactivity falls to safe levels
retiring the worn our plant by taking it apart and storing its high and moderate level radioactive parts safely for thousands of years
nuclear meltdown
a coolant, usually water, circulates through the reactor's core to remove heat and keep the fuel rods and other reactor components from melting and releasing massive amounts of radioactivity to the environment
the danger in nuclear reactors comes from smaller explosions that can release radioactive materials into the environment or cause a core meltdown because of a loss of coolant water
a containment shell made of thick steel reinforced concrete surround the reactor core to: help keep readioacitve materials from escpaing into the environment, in case there is an internal explosion or a core meltdown. protect the core from outside threats like hurricanes and attacks
the typical nuclear plants takes 10 yrs and $10 billion to build
in 2014 the world's three leading producers of nuclear power were USA, France, and Russia. France generates 75% of its electricty and USA generate 19% of its electrity using nuclear power
advantages of nuclear power
low co2 emissions, no toxic emissions
as long as a reactor is operating safely, the power plant itself has a low environmental impact and a low risk of an accident
disadvantages of nuclear power
theres a high cost of building the plant and operating the nuclear fuel cycle
low net energy
threat of nuclear weapons
nuclear waste
the enriched uranium fuel in a typical nuclear reactor lasts for 3-4 years, after which it becomes a spent, or useless, and must be replaced.
spent fuel rods are so thermally hot and highly radioactive that they cannot be simply thrown away