Glossary

Learn more about the technical terms used in the industry and necessary to understand how energy is generated in a nuclear power plant.

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There are currently 9 glosarioING in this directory beginning with the letter D.
D

Daughter
Nuclide that is generated during radioactive decay. (See "Parent".)

Decay
Nuclear phenomenon where the mass and/or level of energy of a radioactive atom is reduced spontaneously, resulting in the emission of ionising radiation. The most usual forms of decay are the emission of alpha particles, beta particles, electron capture and spontaneous fission.

Decay chain
Series of radionuclides in which each member turns into the next one by means of radioactive decay, until a stable nucleus is finally reached.

Degree of burn-up
Amount of energy extracted from one unit of mass of a nuclear fuel from the moment it is inserted into the reactor. It is usually expressed in megawatts hour (or day) per ton of fuel. In a nuclear fuel and for a given fissionable nuclide, ratio between the number of atoms split and those present initially. It is usually expressed as a percentage.

Depleted
Material in which the isotopic abundance of the nuclide considered of interest is less than the natural one.

Derived air concentration limit (DACL)
Average annual activity concentration in inhaled air which, in the event of it being breathed by the standard man for a working year of 2,000 hours, results in an intake equal to the annual intake limit. It is expressed in becquerel per cubic metre (Bq/m3).

Dose
Unless otherwise stated, the term dose is used to express more simply the term of effective dose (formerly effective equivalent dose). In nuclear medicine practice, as happens with commonly used terminology, the term dose is used incorrectly to refer to: - The amount of emitting substance (expressed as weight or activity) in the case of a non-encapsulated source administered to a patient (similarly to a dose of medication). - The energy radiated by a source or transported by a beam; in the case of the individual energy of photons or particles, it is expressed in MeV.

Dosimeter
Instrument or device that enables an absorbed dose, an exposure or any other radiological amount to be measured or assessed. Dosimeters use different procedures for measuring the dose: radiation-sensitive photographic emulsions (photographic dosimeter), materials that absorb the radiation energy and then release it as light (thermoluminiscent dosimeters), chemical substances that change in the presence of radiation (chemical dosimeters, Fricke dosimeters), an electrical condenser (condenser dosimeter), etc. There are also different types of dosimeters based on their use: pocket, lapel, handheld, pen, etc.

Dosimetry
System for measuring and recording absorbed doses.