We are all exposed to a certain level of radiation that we cannot avoid. This is called background radiation.
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Sometimes we are exposed to higher levels of radiation, through things we do, or places we visit. There is also the concern that we might at some time be exposed to very high levels of radiation due to nuclear weapons or an accident at a nuclear power station.
Are you at
risk from nuclear radiation?
To calculate your level of radiation exposure in a year. Click
Dose.
What harm can radiation do?
Exposure to radiation can cause
loss of hair
skin burns
sterility
cancer
genetic defects (mutations)
What safety precautions are recommended?
The two most important issues for safety are
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the
wearing of protective clothing
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and
minimising the amount of exposure to the radiation
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People who work
with radioactive materials wear radiation badges. These badges contain
film that is sensitive to radiation. the film is developed to show how
much radiation the person has been exposed to.
Natural radioactivity
This, in general, does not present a danger. Background radiation due to
cosmic radiation in space and due to radioactive substances like Uranium
in the soil give rise to low levels of radiation that do not cause
damage to health. Radon gas is one example of natural radioactivity that
could present a health risk. For more information on the danger of Radon
click here.
Artificial Radioactivity
This takes a number of different forms many of which could involve
danger.
Many artificially produced radioactive isotopes are used in Industry and
in Medicine. These could present a risk to those who use them.
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What is radioactive fallout? This is where radioactive particles are deposited on the surface of the Earth after they had been released into the atmosphere either by nuclear weapons or by discharge from a nuclear power station. |
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When a nuclear
weapon is exploded close to the Earth's surface, a fireball develops.
Inside the fireball and stem of the bomb cloud the radioactive particles
become attached to heavier particles. These heavier particles then act
as ballast.The heavier bits of matter fall back to earth within minutes,
forming an extremely localized fallout, which is called fallback. Less
massive but easily visible particles, carried downwind by the bomb
cloud, fall within several hours, and are referred to as local fallout.
The extent of local fallout depends on the size of the explosion, where
it happened and the strength and direction of the winds. Microscopic
particles stay aloft for longer periods of time. This is called global
fallout. These particles may remain there for considerable periods of
time.
Within the first hour after the explosion, most of the extremely
short-lived substances (half-lives, measured in seconds or minutes)
decay, and the total radioactivity from the bomb decreases more than a
hundredfold. Most of the remaining radioactivity is due to fission
products with long half lives like strontium-90 which has a half-life of
28 years. These long-lived species constitute the long-term radiation
hazard. Long-lived radionuclides, such as strontium-90 may exist for
many years as a potential hazard, primarily through contamination of the
foods that are consumed by humans.
Although radioactive iodine-131 is extremely short-lived (half-life, eight days), it can cause serious damage to the thyroid gland. Soon after a nuclear accident, grass, which has been contaminated with iodine-131 is consumed by cows. The radioactive iodine then appears in their milk, which is usually consumed within a few days of production. When large amounts of radioiodine accumulate in the thyroid, it may result in thyroid cancer.
More Information
Radiation Protection
Ireland
Radiation
safety
FAQ on
safe dose of radiation