Chapter 7 - The Fires of Nuclear Fission Flashcards Preview

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Flashcards in Chapter 7 - The Fires of Nuclear Fission Deck (11):
1

How much electricity is generated from nuclear power plants?

15%

2

Who invented nuclear power?

Hahn, Meitner, Strassman
-bombarded uranium with neutrons --> made barium (you can't usually change and element into a new element)
Ur + n --> Ba + Kr

3

What is fission?

taking a large atom and splitting it into 2 or more smaller atoms
-extra neutrons --> unstable isotope --> splits atom's nucleus --> makes more neutrons (chain reaction)

4

A
X
Z

A: mass #
Z: atomic #
X: element symbol

5

Chemical vs. Nuclear Reactions

Chemical:
-atoms don't change
-no neutrons
-mass conserved
-any isotopes

Nuclear:
-atoms change
-neutrons (don't cancel)
-mass (mostly) conserved
-specific isotopes (notation)
-many products (random, complicated)

6

Different types of uranium

Uranium-235 (.71%), Uranium-234 (.0054%), Uranium 238 (99.28%)
-all are radioactive
-Uranium-235 is only one good for energy, others stop the chain reaction

7

Nuclear power plant

similar to coal burning: steam
differences: nuclear uses heat from chain reaction (nuclear energy), water stays in cycle
problems: thermal pollution (increase in temp of lake where water is taken from --> affects ecosystems)

8

What controls the chain reactions?

Control rods
-boron/cadmium
-absorb excess neutrons
-move up/down to control heat produced

9

Chernobyl

reactor blew up, cheap graphite rods caught fire
results:
-50 different reactive isotopes were released with half-lives spanning from 2 hours to 24,000 years, shot 1.5 miles in sky
-1000 injuries and 31 deaths
-health threatening levels of radioactive material found in at least 20 nations afterwards, 25 million people exposed
-an estimated 7,500 to 1 mil future cancers
-distrust of government (the kept cheap material a secret)

10

Tsunami and Fukushima Power Plant

reactors 1, 2, 3 melted down (luckily 4/5 were shut down at time)
-ocean contamination --> constantly moving so most radioactive material was diluted

11

What is enrichment?

making nuclear fuels
-achieving critical mass (mass in order to create chain reaction)