Glossary

Energy deposited by ionising radiation per unit mass of medium. It is a physical value whose unit is Gray (Gy).

Unforeseen event that causes damage to a facility or disrupts its normal operation, and which can result in one or more people receiving a dose higher than the established limits. (See "Incident".)

Factor that takes into account the strengthening of the theoretical flow of the direct radiation beam when it goes through a shielding material; it is originated by beam scattering caused by the multiple collisions undergone that are originated by the thickness of the material being considered.

Mechanism through which a non-radioactive atom becomes a radioactive one by being subjected to an irradiation process with neutrons or charged particles. Since only high-energy gamma rays cause activation, substances that are subjected to gamma radiation usually do not become radioactive.

Radioactive nuclide that results when irradiating a stable material with particles owing to a nuclear capture reaction.

Physical magnitude that measures the number of spontaneous transformations (see "Radioactivity") which occur in a substance per unit of time. The unit is the becquerel (Bq).

Acronym for "As Low As Reasonably Achievable". It is one of the criteria of radiology and aims to achieve that exposures to ionizing radiations are as low as reasonably possible.

A Helium-4 nucleus emitted during nuclear decay. By extension, any group of two protons and two neutrons. It is represented by the symbol α.

Maximum values, referred always to the last 12 months, of the doses that can be received by professionally exposed workers and members of the public. These values are set legally and do not take into account the doses resulting from the naturally occurring radioactive materials or exposure undergone as a result of medical examinations or treatments. The dose limits are applied to the sum of the doses received by external exposure during the period being considered, and of the integrated internal dose resulting from radionuclide intake that may have taken place during the same period.

Activity which, upon entering the organism of a given individual, causes an integrated internal dose equal to the established annual dose limit.

Area where 1/10 of the annual dose limits can possibly be exceeded, and where it is very unlikely that 3/10 of those values will be reached, and therefore access to that area is regulated.

According to regulations, an area established around a major nuclear or radioactive site which is under the control of the facility's operator.