Radiation, Nuclear Power And Japan - Eayh Final

Front 1

ionizing radiation

Back 1

radiation with sufficient energy to eject electrons from atoms. this process is called ionization.

Front 2

non-ionizing radiation

Back 2

radiation without sufficient energy to produce ionization

Front 3

electro magnetic radiation

Back 3

UV, visible night, x-ray, EMF

electric field and magnetic field traveling together; no mass, no charge

Front 4

particulate radiation

Back 4

alpha particles, beta particles, neutrons

have mass and (alphas and betas) charge

Front 5

natural sources of radiation exposure

Back 5

those of natural origin by unperturbed by human activities

those of natural origin affected by human activities (enhanced natural sources)

e.g. the sun, the soil

Front 6

man-made sources of radiation

Back 6

those specifically produced by humans

e.g. medical devices, consumer products, and the fallout from atomic bomb testing

Front 7

sources of ionizing radiation

Back 7

radionuclides - atoms that spontaneously undergo radioactive decay, emit radiation upon decay, characterized by mode of decay and half-life, are always "on"

machines - electron and x-ray sources, can be switched on and off

Front 8

three types of ionizing radiation and their penetrating power

Back 8

alpha particle - hits paper

beta particle - goes through paper and hits body

gamma rays - go through paper, body, and metal

Front 9

external irradiation

Back 9

radiation sources is outside the body

most risk from x-rays or gamma rays (able to penetrate the body)

Front 10

internal irradiation

Back 10

radiation source is inside the body
most risk from alpha and beta particles (deposit a lot of energy over short distances)

Front 11

sources of ionizing radiation exposure

Back 11

natural background (82%)
man-made (18%)


man-made:
medical xrays (58%)
nuclear medicine (21%)
consumer products (16%)
occupational exposures (5%)

Front 12

ionizing radiation effects

Back 12

deterministic:
- severity is a function of dose
- threshold exists
- examples: skin reddening , mental growth and retardation, cataract formation

random:
-risk is a function of dose
- no threshold
- example: cancer

Front 13

nuclear fission

Back 13

"fission" = nuclear reaction in which an atom splits into 2 'fission fragments' and gives off energy

enriched uranium i a great fission fuel

Front 14

criticality

Back 14

when a U-235 atom undergoes fission, it gives off two or three neutrons. if there are no other U-235 atoms near by, those neutrons fly off. if the U-235 is part of a mass of uranium , so there are other U-235 atoms nearby, then one of three things happens:

critical: on average exactly one of the free neutrons from each fission hits another and causes it to undergo fission (stable temperature)

subcritical - if on average less than one of the free neurons hits another (induced fission will end)

supercritical - if on average more than one of the free neurons hits another (mass heats up)

Front 15

japan nuclear accident

Back 15

fukushima I nuclear power plant and fukushima II nuclear power plant (both operated by the tokyo electric power company)

March 11, 2011 - magnitude 9 earthquake

units 4,5,6 had been shut down prior for maintenance. the remaining reactors shut down automatically after the earthquake; the remaining heat of the fuel was cooled with power from emergency generators

the subsequent tsunami disabled the emergency generators

partial meltdowns, explosions, etc.

Front 16

magnitude of the event

Back 16

units 1,2, and 3 = level 7
unit 4 = level 3

Front 17

radionuclides potentially released in a nuclear power accident

Back 17

iodine-131 (8 day half-life) - thyroid

cesium-137 (30 year half-life) - tissues

strontium-90 (29-year half life) - bone
plutonium (multiple isotopes) - bone and liver

Front 18

where does our energy come from?

Back 18

coal 50%
nuclear 19.3%
natural gas 18.7%
hydro-power 6.7%
oil 3%
other 2.3%

Front 19

usa today editorial may 16, 2007

Back 19

rebirth of the nuclear power industry

electricity demand is going to jump 40%

nuclear energy is a green alternative to coal

Front 20

risk analysis

Back 20

risk assessment, risk management, risk communication

risk = probability x consequences

risk-benefit analysis

risk-risk analysis