nuclear physics Flashcards
alpha particles
-charge:+2
-mass number decreases by 4
-atomic number decreases by 2
range in air:few cm
penetration: stopped by paper
-ioniation power:high
beta particle
-charge:-1
-atomic number increases by 1
-range in air: fews 10s of cm
penetration: stopped by a few mm of aluminium
ionisation power: medium
gamma radiation
electromagnetic radiation
-charge:0
-range in air:infinite
-penetration:stopped by a few mm of lead
-ionisation power:low
background radiation
the radiation that exists around us all the time
half-life
-the average time it takes for the number of nuclei of a sample of radioactive iostops decrease by half
-count rate to fall to half of original level
contamination
the unwanted presence of materials containing radioactive atoms on other materials
-often due to radiation leak
-material becomes radioactive
irradiation
the process of exposing a material to alpha, beta or gamma radiation
-doesnt make material radioactive
-can kill living cells
least unstable nuclei…
have the longest half-lives, emit little radiation during a long period of time
most unstable nuclei…
shortest half lives. decay is rapid with a lot of radiation in a short period of time
medical uses of isotopes
-detect tumours
nuclear fission
-the splitting of a large, unstable nuclei into smaller nuclei
nuclear fusion
joining of two light nuclei to form a heavier nucleus
nuclear reactors
Within the core of a nuclear reactor, fuel rods are surrounded by water
The fuel rods release energy which is transferred to the water molecules, heating the water
The hot water is pumped into a heat exchanger
Tubes carrying a separate supply of water run through the heat exchanger
The energy is transferred by heating from the hot water in the heat exchanger to the cooler water in the tubes
This cools the hot water from the control rods enough to be returned to the reactor
The water in the tubes is heated and turns to steam
The steam turns a turbine which generates electricity
control rods
rods that can be raised or lowered to absorb nuetrons and control the speed of the chain reaction
concreate shield
a thick layer of concrete around the reactor to bloc harmful radiation from the radioactive by-producys
nuclear fuel
uranium or plutonoium isotopes that split when hit by a nuetron, releasing energy. Fuel is in the rods to allow the realeased nuetrons to continue the chain reaction
coolant
a fluid that absorbs heat from the fission reaction and transfers it to water to produce steam for turning turbines
