A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

G
general emergency:
See emergency class.

geological disposal:
See disposal.

geological repository:
See repository.

geosphere:
Those parts of the lithosphere not considered to be part of the biosphere.
In waste safety, usually used to distinguish the subsoil and rock (below the depth affected by normal human activities, particularly agriculture) from the soil that is part of the biosphere.

gray (Gy):
Name for the SI unit of kerma and absorbed dose, equal to 1 J/kg.

H

half-life, T1:
1.   For a radionuclide, the time required for the activity to decrease, by a radioactive decay process, by half.
Where it is necessary to distinguish this from other half-lives (see (2)), the term radioactive half-life should be used.
The half-life is related to the decay constant, l, by the expression:

2.   The time taken for the quantity of a specified material (e.g. a radionuclide) in a specified place to decrease by half as a result of any specified process or processes that follow similar exponential patterns to radioactive decay.

  • biological half-life: The time taken for the quantity of a material in a specified tissue, organ or region of the body (or any other specified biota) to halve as a result of biological processes.
  • effective half-life, Teff: The time taken for the activity of a radionuclide in a specified place to halve as a result of all relevant processes.
     (or
    )
    where Ti is the half-life for process i.
  • radioactive half-life: For a radionuclide, the time required for the activity to decrease, by a radioactive decay process, by half.
    The term ‘physical half-life’ is also used for this concept.

health effects (of radiation):

health professional:
An individual who has been accredited through appropriate national procedures to practise a profession related to health (e.g. medicine, dentistry, chiropractic, podiatry, nursing, medical physics, radiation and nuclear medical technology, radiopharmacy, occupational health). [40]
Used in the BSS to distinguish from a medical practitioner, who satisfies additional criteria.

hydrological dispersion:
See dispersion.