P3

RADIOACTIVE MATERIALS

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  • Created by: jac
  • Created on: 23-06-10 11:49

Nuvlear radiation

Nucleus - contains prtons and neutons (majority of atoms mass)

Electrons - tiny and go around the outside of nucleus. Paths Make up space. but is mainly empty space.

Number of protons in an elements atom is the same eg. Carbon 6 , Hydrogen 7

Neutrons is not fixed. many elements have different isotypes- same proton dif neutron

Common carbon isotopes- carbon 12, (averge carbon) 6 protons and 6 neutrons

Carbon 14, 6 protons and 8 neutrons

Eche element hs 1 or 2 stable isotopes. unstable isotopes(c14) cause decay-emit radiation

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- Unstable atoms can decay at any time

- You never know when it will happen as no enviromental factors cause it

its completly in their own random time

- When it does decay it 'spits out' one of three types of radiation

- ALPHA

- BETA

- GAMMA

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Akpha Beta Gammma

Alpha

  • Slow and heavy
  • Dont penetrate very far - stopped by substance easily
  • two protons two neutrons
  • stopped by thin paper - skin .... anything equivelent

Beta

  • quiet fast and quiet small
  • Penetrate moderately
  • released by particles with too many neutrons
  • during decy neutrons turn to protons changing element and emitting a beta particle
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Gamma

  • happens when an alpha or beta particle need to get rid of extra energy
  • it is EM RADIATION
  • They penetrate a very long way
  • think lead any thick concrete can stop it.
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Half Life

  • As unstable nuclei decay, radioactivity of the entire source decreases
  • Activity never dissapears its why we measure it as a HALF life

HALF LIFE is the TIME TAKEN for HALF of the Radioactive atoms now present to DECAY

SHORT HALF LIFE - ACTIVITY FALLS QUICKLY

lONG HALF LIFE - ACTIVY FALLS SLOWLY

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How to work out half life

.

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Nuclear radiation dangers

HIGH DOSE - Radiation sickness completely killing cells

LOWER DOSE - damage cells, cause cancer

Alpha - more dangerous inside the body

Beta and gamma - more dangerous outside the body

Irradation - being exposed to radiation withought contact with source. damagin when i radioactive area not opnce left

Contamination - infected with it by breathing it in or drinkin, still exposed to radiation after being exposed

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Unit for radiation exposure

SIEVERTS - (Sv) millisieverts (mSv)

takes into considertaion:

-type of radiaton

- which body part

- how much radiation

2 msv/year - everyone

9msv/year - airline crew

20 msv/year - industry workers

100 - lowest increse to cause cancer

100 msv/year - lowest to cause radiation sicknes

5000 msv/year kill half who revievie with a month

10 000 msv/year fatal within weeks

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People with higher risk to exposure

uranium minors

people working in nuclear power plants

airline staff

miners

medical staff - radiographers

nuclear researchers

These people in britain have to monitar their radiation and have regular check ups

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using nuclear radiaiton

natural substances- soil , air , living things

Space (cosmic rays) - mainly the sun

Human activity - nuclear waste , nuclear exxploxions (only 1 %)

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iT CAN ALSO BE USEFUL

Treating Cancer

  • High dosesw of gamma rays kill cells
  • exact dosage is directed to exact place to kill cancer cells, without damaging normal ones
  • some normal cells are damaged making the very ill after however if cancer cell is killed it is okay. And they eventually recover.

Sterilising Equipment

  • gamma rays sterelise equipment by killing microbes
  • Needs a good long half life so dont have to replace onject often

Sterelising Food

  • also by killing microbes
  • keeps it fresher longer without freezing or preserving otherways
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ELECTRICITY

  • eLECTRICITY IS A SECONDARY ENERGY ASOURCE - MADE BY OTHER FUELS BURNING FIRST
  • convenient cos can be transmitted over national grid long distances

Energy released from fuel and used to generate steam > >>>

steam turns a turbine > >>>>>>>

a generator converts the movement in electricity (kenetic energy)

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IS NOT 100 % EFFICIENT

  • BECAUSE IT WASTES ALOT OF ENERGY
  • Sankey diagrams show exactly how much energy is used on what and whats wasted
  • Width of arrow poportional representation of how much enrgy used on that thing

EFFICIENCY = USEFUL ENERGY OUT PUT

ENERGY INPUT

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  • Fossil fuel is not ideal... blah blah blah all the chemistry ****
  • greenhouse...etc
  • RENEWABLE SOPURCES
  • wind,solar,wave,tidal,hydroelectric,geothermal
  • These will never run out
  • but are unreliable as some depend on weather
  • WIND
  • own generator triggerd when wind makes movement of blades
  • need windy area on hill near shore or off shore
  • needs wind power of 3-4 m/s, must shut if too stormy.
  • no co2 emmisions no fuel costs, 1% of uks overall elctricity production
  • SOLAR POWER
  • silicon cells convert light directly into elctricity
  • only generated during day but energy can be used to charge batteries during day for night.
  • need allot of sun : (
  • no co2 emmisions or fuel costs
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Nuclear Fuels

  • Nuclear fuel (like uranium) lety out alot of energy during nuclei changes
  • Nuclear fision when something hits uranium causing to split into two smaller nuclei then those nucleui split again into 2 or 3 more each. MAKES ALOT OF ENERGY
  • Because so much is made it must be controlled
  • control rods absorb enrgy as well as slow down the making process
  • water or c02 is used to to cool things down.
  • Excess heat is turnt into steam to drive turbine
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waste level

LOW LEVEL WASTE

  • paper, clothes, gloves
  • burried in land fills

INTERMEDIATE LEVEL WASTE

  • eg. metal cases of fuel rods
  • radioactive for long, up to thousands of years
  • sealed in concrete then steel containers to store waste

High Level Waste

  • Generates ALOT of heat
  • cooled storage for fifty years
  • then moved to perminant place.
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Comments

alex colton

really good and imformative :-D few spelling mistakes and theres nothing on the how to work out half life card(or it just isn't showing up) BUT great cards overall

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