Radiation is the process by which energy in the form of waves or particles
is emitted from a source and spread through the surrounding medium or
Types of radiation
Some radiations such as light and sound are essential to some forms of
life while others are harmful. Some radiations cause an alteration in
the materials they pass through by disturbing the outer parts of atoms,
causing an electrical charge. Atoms in this state are called ions: hence
the name ionising radiation. The release of ionising radiation is called
Types of ionising radiation
Alpha radiation consists of helium atoms without their electrons.
Beta radiation consists of fast-moving electrons.
Gamma radiation is electromagnetic like light but of shorter wavelength.
Cosmic radiation consists of the nuclei of atoms and electrons, positrons
and other sub-atomic particles.
Sources of radiation
The average dose of ionising radiation which people receive depends a
lot on where they live and work. Typical figures for a member of the public
50 -70% from radon gas, which emits alpha particles
5 - 15% from the ground and buildings
10 - 14% from food and drink
12 - 14% from cosmic radiation
A total dose of 2.2 millisieverts (2.2mSv) per year is average for a member
of the public in the UK, and radiation doses from other sources may be
compared to this amount of background radiation.
Diagnostic radiology (x-rays)
Nuclear medicine (radioactive substances introduced into the patient
for diagnosis or treatment)
Radiotherapy (uses high power x-rays or radioactive sources to treat
Damage due to radiation
The potential for damage to body tissue due to ionising radiation depends
on the energy absorbed, the type of radiation and the energy associated
with each type together with the type of tissue. Radiation is used medically
when its advantage outweighs its potential for harm.
Uranium is the principal radioactive element used in the nuclear powered
generation of electricity and in nuclear bombs.
The mining of uranium causes cancer in miners and some of the element
finds its way into the surrounding land and water. The transportation
of uranium involves the danger of theft or accident leading to its dispersal
with a poisoning of the environment. The explosion of the power station
at Chernobyl [link to be inserted] has made areas of Belarus uninhabitable.
Some radioactive materials remain active for thousands of years and this
makes difficult the safe disposal of nuclear waste.
When a nuclear weapons explodes there is a release of ionising radiation
which along with the blast and heat results in devastation many times
greater than that caused by high explosive. If the explosion is at ground
level quantities of irradiated material are drawn into the atmosphere
eventually to fall to earth threatening the lives of people far away.
Ionising radiation is a naturally occurring phenomenon which, though it
has useful medical applications, is damaging to health unless strictly
controlled. To produce ionising radiation deliberately in the process
of generating nuclear energy and its waste products is to increase the
risk from ionising radiation in the environment not for decades or even
centuries but for millennia. However, it may be argued that nuclear energy,
by producing a source of energy without emitting greenhouse gases has
benefits. It is much harder to argue the case for producing ionising radiation
deliberately in the process of manufacturing nuclear weapons, since these
weapons, if used, would have a catastrophic effect on the populations
targeted and on the environment.