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Percent use in world energy use
EIA (energy information administration) predicts 28% increase in world energy use by 2040
how does percent use fit into the global energy mix?
coal down, NG nuclear petroleum renewables up
how does percent use fit into the US energy mix?
solar increase most, natural gas increase second, wind third
how much of the world’s electricity does nuclear power provide
17%
how much of the world’s total energy does nuclear power provide
4.8%
Are they rising in importance or falling? or neither? why might that be?
rising bc increase in capacity use
Which countries rely the most on nuclear power?
France, Belgium, Sweden in order
Fusion
fusing of atomic nuclei
Fission
splitting of atomic nuclei
nuclear reactor
devices that produce controlled nuclear fission
What uranium isotope is needed for reactors? %?
uranium-235 .07% of all natural uranium
Problems associated with enriching that .07% of uranium-235?
increase concentration to 3% BUT releases chain reaction and meltdown occurrence
meltdown
nuclear accident in which coolant system fails = nuclear fuel becomes so hot it forms a molten mass. breaches to containment of reactor. contaminates outside environment with radioactivity
How does a "chain reaction" work with nuclear fuels
fission reactors split uranium-235 by neutron bombardment = release more neutrons than it took to create first splitting = they strike other uranium-235 atoms = releasing more neutrons, other kinds of radiation, fission products, heat
Cooling systems? How many and what is their arrangement?
primary coolant loops and pumps circulate coolant through reactor. heat leaves reactor vessel, coolant goes in
moderator
primary coolant
control rods
contain materials that capture neutrons, move out of core = chain reaction increases, move into core = reaction slows. full insertion = stops fission reaction
What happens to the radioactive fuel waste? What if its military? Difference?
WIPP waste isolation pilot plant in carlsbad, NM for transuranic waste disposal
What is a breeder reactor?
type of nuclear reactor designed to produce more fissionable material (fuel) than it consumes = “breeding” new fuel from readily available fertile materials
Basic difference between its core and a conventional nuclear core? What is produced?
breeder reactors typically don’t have moderator = allows fast neutrons to travel through core. fissile material
alpha radiation
least penetrating (helium nuclei)
beta radiation
moderate penetration (high-energy electrons)
gamma radiation
most penetrating due to its wave-like nature (high-energy photons)
What are Alpha, Beta and Gamma radiation?
three types of ionizing radiation emitted from unstable atomic nuclei during radioactive decay
What changes to atomic structure result from the emission of the particles/waves?
alpha: atomic number decreases by 2, mass number decreases by 4
beta: increases atomic number by 1, decreases neutron count by 1
gamma: does not change as it only releases energy from excited nucleus
Can radioactive elements enter ecosystems? How/why?
nuclear fuel cycle
nuclear fuel cycle
mining/processing of uranium to controlled fission, reprocessing of spent fuel, decomissioning of power plants, disposal of radioactive waste
Transmission of electromagnetic energy into and out of the atmosphere (how different gases absorb energy)
CO2 and other absorb different wavelengths, where there isn’t overlap with CO2, absorbance is greater than there would otherwise be
Projections for future CO2 emissions from developed vs. undeveloped economies?
developed: decrease in CO2 emissions, undeveloped: increase
Uncertainty in modeling? Why?
limitations of climate models, incomplete?
How does the greenhouse effect work?
gases in atmosphere absorb (trap) infrared radiation (heat) similar to glass roof of greenhouse = warm planet’s surface
Carbon cycling: Tons of emissions? Plant storage? Soil storage? flux to oceans and atmosphere?
65,500 billion metric tons. largest storage reservoir = ocean. plants store carbon via photosynthesis. soil = major carbon sink via the organic matter within it. ocean absorbs carbon dioxide from air
biosphere (plants) gaining carbon?
photosynthesis: absorb C from atmosphere and use solar energy to convert it into sugars for growth. gaining 3.2 gigatons of carbon/year
