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REGDOC-3.6, Glossary of CNSC Terminology - Glossary - A

A1, A2 (A1, A2)

Ha[ve] the same meanings as in the IAEA Regulations. (Source: Packaging and Transport of Nuclear Substances Regulations, 2015)

Note: A1 and A2 are values specific to each radionuclide and are used to determine the activity limits for transport packages.

abandon (abandonner)

Remove from regulatory control.

abiotic (abiotique)

Relating to the non-living parts of the environment such as air, rock, soil and water. Some abiotic components are topography, hydrology, drainage, climate, meteorology, and land-use patterns by members of the public.

abnormal incident (incident anormal)

An abnormal occurrence that may have a significant cause and/or may lead to more serious consequences.

Aboriginal peoples of Canada (peuples autochtones du Canada)

Includes the Indian, Inuit and Métis peoples of Canada. (Source: Constitution Act, 1982)

Note: Outside of legal contexts, the term First Nations is used in place of the term Indian. See also Indigenous peoples.

absent from duty (absent de son poste)

Not available on a day normally scheduled for duty.

absorbed dose (D) (dose absorbée [D])

The quotient, in gray, obtained by dividing the energy absorbed through exposure to radiation by the mass of the body or part of the body that absorbs the radiation. (Source: Radiation Protection Regulations)

See also effective dose, equivalent dose.

acceptance criteria (critères d’acceptation)

With respect to nuclear facilities, specified bounds on the value of a functional or condition indicator used to assess the ability of a structure, system or component to meet its design and safety requirements.

acceptance parameter (paramètre d'acceptation)

A plant parameter that characterizes plant response and has a defined acceptance criterion as a limit for the acceptable range of values.

access control (contrôle de l’accès)

A system for allowing only approved individuals to have unescorted access to the security zone and for ensuring that all other individuals are subject to escorted access.

access denial (refus d’accès)

A denial of access to an adversary, through the exercise of sufficient force, to a vital area of a nuclear facility until an offsite response force intervenes effectively.

accident (accident)

Any unintended event, including operating errors, equipment failures or other mishaps, the consequences or potential consequences of which are significant from the point of view of protection or safety. With respect to nuclear criticality safety, the term accidents or accident sequences means events or event sequences, including external events, that lead to violation of the subcriticality margin (that is, to exceeding the upper subcritical limit).

accident conditions (conditions d’accident)

Deviations from normal operation more severe than anticipated operational occurrences. Accident conditions include design-basis accidents and beyond-design-basis accidents.

accident management (gestion des accidents)

The taking of a set of actions during the evolution of an accident to prevent the escalation of the accident, to mitigate the consequences of the accident, and to achieve a long-term safe stable state after the accident.

accidents or accident sequences (accidents ou séquences d’accident)

See accident.

account audit (vérification comptable)

An examination by IAEA or CNSC inspectors of the nuclear material accounts, records and reports at a facility to check for completeness, correctness, internal consistency and consistency with the Member State reports.

accounting (comptabilisation)

A system of records and reports that shows, for each material balance area (MBA), the inventory of nuclear material and the changes in that inventory, including receipts into and transfers out of the MBA.

accounting records (relevés comptables)

A set of data kept at each facility or location outside facilities showing the quantity of each category of nuclear material present, its distribution within the facility and any changes affecting it. For each material balance area, accounting records contain:

  • all inventory changes, so as to permit a determination of the book inventory at any time
  • all measurement results that are used for determination of the physical inventory
  • all adjustments and corrections that have been made in respect of inventory changes, book inventories and physical inventories
accredited laboratory (laboratoire agréé)

With respect to drug testing for fitness for duty, a laboratory accredited by the Substance Abuse and Mental Health Services Administration to analyze and report the results of urine drug specimen tests.


annual compliance report

Act (Loi)

The Nuclear Safety and Control Act. (Sources: All regulations pursuant to the Nuclear Safety and Control Act)

Note: In this glossary, unless otherwise indicated, Act means the Nuclear Safety and Control Act. The CNSC also uses “NSCA”, especially when distinguishing between two or more acts under discussion.

action level (seuil d’intervention)

A specific dose of radiation or other parameter that, if reached, may indicate a loss of control of part of a licensee’s radiation protection program and triggers a requirement for specific action to be taken. (Source: Radiation Protection Regulations)


A specific dose of radiation or other parameter that, if reached, may indicate a loss of control of part of a licensee’s radiation protection program or environmental protection program, and triggers a requirement for specific action to be taken. (Source: Uranium Mines and Mills Regulations)

Note 1: An action level is an indicator of a potential loss of control of part of a program and/or control measure(s). An action level is said to be exceeded if it goes either above an upper limit or below a lower limit, depending on the parameter being measured. Exceeding an action level signals, to both the licensee and regulator, a potential reduction in the effectiveness of the program and/or control measure(s) and may indicate a deviation from normal operation.

Note 2: Action levels are proposed by the licensee and submitted for review and approval by the CNSC. Within the licensing basis for a specific site, action levels should be adjusted (subject to CNSC review and approval) depending on changes to site activities or processes.

Note 3: Exceeding an action level triggers a requirement for a specific action to be taken. Exceeding an action level is not considered a non-compliance; however, failure to respond appropriately is a non‑compliance. To respond to an exceedance, a licensee must follow:

action notice (avis d’action)

A written request that a licensee or a person subject to enforcement action take steps to correct a non‑compliance that is not a direct contravention of the Nuclear Safety and Control Act, applicable regulations, licence conditions, codes or standards, but which can compromise safety, security or the environment and may lead to a direct non‑compliance if not corrected.

active engineered nuclear criticality safety control (contrôle technique actif de sûreté‑criticité nucléaire)

See engineered (nuclear) criticality safety control.

active threat (incident en cours)

One or more adversaries who randomly or systematically inflict death or grievous bodily harm in a very short period of time. Also called active shooter.

activity (activité)

The number of nuclear transformations occurring per unit of time, as measured in becquerels. (Source: Packaging and Transport of Nuclear Substances Regulations, 2015)


See licensed activity.


The condition of being active or moving about.


A particular occupation or pursuit.

actual full cost (coût entier réel)

The full cost verified by audited financial statements. (Source: Canadian Nuclear Safety Commission Cost Recovery Fees Regulations)

adaptive management (gestion adaptative)

A planned and systematic process for continuously improving management practices [primarily environmental] by learning from their outcomes. [For an environmental assessment (EA),] it involves, among other things, the implementation of new or modified mitigation measures over the life of a project to address unanticipated environmental effects. (Source: Practitioners Glossary for the Environmental Assessment of Designated Projects Under the Canadian Environmental Assessment Act, 2012 [1]).

Note: The need to implement adaptive management measures may be determined through an effective follow-up program. See also corrective action.

additional safety feature (caractéristique de sûreté additionnelle)

See complementary design feature.

ad hoc bioassay (essai biologique ponctuel)

See non-routine bioassay.

adjusted book ending (stock comptable final)

See book-adjusted ending.

administrative (nuclear) criticality safety control (contrôle administratif de sûreté‑criticité [nucléaire])

Either an enhanced or simple administrative control:

  • enhanced administrative control: a procedurally required or prohibited human action, combined with a physical device that alerts an operator to take action to maintain safe process conditions, or that otherwise adds substantial assurance of the required human performance
  • simple administrative control: a procedural human action that is prohibited or required to maintain safe process conditions
administrative monetary penalty (AMP) (sanction administrative pécuniaire [SAP])

An administrative penalty imposed without court involvement in response to the violation of a regulatory requirement. There is no criminal record associated with an AMP and an AMP can be applied against any party subject to the Nuclear Safety and Control Act, including non‑licensees.

adversary (adversaire)

A person performing malevolent acts in pursuit of interests harmful to the facility; an adversary may be an insider or an outsider.

adverse information (renseignement défavorable)

Information about a site access security clearance (SASC) applicant or holder – whether collected by the licensee, outside agencies or a trusted agent – that is questionable in nature, unclear or does not match the information provided by the applicant. The information collected may indicate:

  • a gap in history
  • a poor credit rating
  • a criminal conviction
  • links to a criminal element
  • concerns related to the reliability or trustworthiness of a SASC applicant or holder

Atomic Energy of Canada Limited

affected facilities (installations touchées)

Onsite locations under duress and the components, the affected facility/unit(s) and their components that control, contain and cool nuclear substances and prevent the release of nuclear substances.


See aging.

aging (vieillissement)

The gradual change of the characteristics of a structure, system or component over time or with use. Note: One or more mechanisms may drive physical aging. Physical aging is due to physical, mechanical, thermal, electrical, chemical, irradiation and/or biological processes (aging mechanisms). Non‑physical aging means becoming out of date (obsolete) due to the evolution of knowledge and technology and associated changes in codes and standards.

aging degradation (dégradation due au vieillissement)

Aging effects that could impair the ability of a structure, system or component to function within its acceptance criteria.

aging effects (effets du vieillissement)

Net changes in the characteristics of a structure, system or component that occur with time or use and are due to aging mechanisms.

aging management (AM) (gestion du vieillissement)

Engineering, operations, inspection and maintenance actions to control, within acceptable limits, the effects of physical aging and obsolescence of structures, systems and components.

aging management program / aging management plan (AM program/plan) (programme ou plan de gestion du vieillissement [programme ou plan de GV])

A set of policies, processes, procedures, arrangements and activities that provides direction for managing the aging of a nuclear power plant’s structures, systems and components (SSCs). AM program refers to the overall integrated aging management program or framework for a nuclear facility, while AM plan refers to a plan that is SSC specific or mechanistic based. Also called lifecycle management plan. Note: The acronym AMP is now reserved for administrative monetary policy.

aging mechanism (mécanisme de vieillissement)

A specific process that, with time or use, gradually changes characteristics of a structure, system or component. Some examples are thermal or radiation embrittlement, corrosion, fatigue, creep and erosion.

agitation (agitation)

The physical movement of Raschig glass rings relative to one another that may cause breakage or gravitational settling.

air kerma (kerma de l’air)

The kerma (kinetic energy released in matter) value for air, in gray, where kerma (K) is defined as:

K = d E t r d m

where dEtr is the sum of the initial kinetic energies of all charged ionizing particles liberated by uncharged ionizing particles in air of mass dm.


See as low as reasonably achievable.

Alcohol Test Committee (Comité des analyses d’alcool)

A scientific committee, under the auspices of the Canadian Society of Forensic Science, that evaluates the scientific, technical and law enforcement aspects of breath alcohol. Note: Its scope includes roadside screening devices, automated breath test equipment, mobile breath testing and provisions to demand blood samples.


See annual limit on intake.

alpha counter (compteur de particules alpha)

An instrument designed and manufactured to detect and count alpha particle emissions.

alpha particle (particule alpha)

A positively charged particle ejected spontaneously from the nuclei of some radioactive elements. Note: An alpha particle is identical to a helium nucleus, which has a mass number of 4 and an electrostatic charge of +2. An alpha particle has low penetrating power and a short range (a few centimetres in air). Alpha particles will generally fail to penetrate the dead layers of cells covering the skin and can be easily stopped by a sheet of paper. However, alpha-emitting isotopes are harmful if ingested.

alpha radiation (rayonnement alpha)

Radiation consisting of alpha particles. See also alpha particle.

alternative activity limit for an exempt consignment (autre limite d’activité pour un envoi exempté)

In respect of an instrument or article, means an activity limit for a consignment that is above the activity level for an exempt consignment set out in the IAEA Regulations and that has been approved as meeting the exemption criteria set out in those Regulations for an instrument or article. (Source: Packaging and Transport of Nuclear Substances Regulations, 2015)


See aging management.

AM program / AM plan (programme ou plan de gestion du vieillissement [GV])

See aging management program / aging management plan.


See administrative monetary penalty or aging management program / aging management plan.

Note: The acronym AMP is now reserved for administrative monetary penalty.

analyst (analyste)

A person designated as an analyst under section 28. (Source: Nuclear Safety and Control Act)

analytical decision level (niveau de décision analytique [niveau critique])

The amount of a count or final instrument measurement of a quantity of analyte at or above which a decision is made that a positive quantity of the analyte is present (measured in becquerels per litre).

annual limit on intake (ALI) (limite annuelle d’incorporation [LAI])

The activity, in becquerel, of a radionuclide that will deliver an effective dose of 20 mSv during the 50‑year period after the radionuclide is taken into the body of a person 18 years old or older or during the period beginning at intake and ending at age 70 after it is taken into the body of a person less than 18 years old. (Source: Radiation Protection Regulations)


authorized nuclear operator; see reactor operator


American Nuclear Society


American Nuclear Standards Institute

anticipated operational occurrence (AOO)(incident de fonctionnement prévu [IFP])

An operational process deviating from normal operation that is expected to occur at least once during the operating lifetime of a reactor facility but, because of appropriate design provisions, does not cause any significant damage to items important to safety or lead to accident conditions. AOO is a plant state. Some examples of AOO are loss of normal electrical power and faults such as a turbine trip, malfunction of individual items of a normally running plant, failure of individual items of control equipment to function, and loss of power to the main coolant pump.


See anticipated operational occurrence.

applicant (demandeur)

An organization or person that has applied to the CNSC for a licence or for certification. For example, an applicant that applies for a licence to construct a nuclear facility has the overall responsibility, and controlling and coordinating authority, for overseeing the safe and satisfactory completion of all design, procurement, manufacturing, construction and commissioning work.


Any person applying for a site access security clearance (SASC) to a high-security site in Canada. Note: CNSC staff who are not inspectors and/or do not hold a Level II Secret Government of Canada clearance will apply for a CNSC SASC to work at the licensed facility.

applicant authority (responsable de la demande)

A position within an applicant’s organizational structure with power to direct the application of financial and human resources.

approved instrument (instrument approuvé)

With respect to breath samples, an instrument of a kind that is designed to receive and make an analysis of a sample of a person’s breath in order to measure the concentration of alcohol in the blood of that person, and which is approved as suitable for the purposes of section 258 of the Criminal Code by order of the Attorney General of Canada.

areal density (densité surfacique)

The product of the thickness of a uniform slab and the density of fissionable material within the slab; hence, areal density is the mass of fissionable material per unit area of slab. Note: For non‑uniform slurries, the areal density limits are valid for a horizontal slab subject to gravitational settling, provided the restrictions for uniform slurries are met throughout.

area(s) of applicability (domaine[s] d’applicabilité)

The limiting ranges of material compositions, geometric arrangements, neutron energy spectra and other relevant parameters (such as heterogeneity, leakage, interaction or absorption) within which the bias of a calculational method is established.

array (réseau)

Any fixed configuration of fissile or fissionable material units maintained by mechanical devices.


atmospheric steam discharge valve

as‑found condition (état observé)

The condition of an item when it was first found, received, inspected or otherwise designated for current use, and prior to any subsequent corrective work being performed on the item (for example, cleaning, calibration, adjustment, servicing, repair or refurbishment).

as low as reasonably achievable (ALARA) (niveau le plus bas qu’il soit raisonnablement possible d’atteindre [ALARA])

A principle of radiation protection that holds that exposures to radiation are kept as low as reasonably achievable, social and economic factors taken into account. Section 4 of the Radiation Protection Regulations stipulates licensee requirements with respect to ALARA.


A professional association, founded as the American Society of Mechanical Engineers.

assembly (assemblage)

See fissile assembly.

assessment (évaluation)

The process and the result of systematically evaluating the protection and safety measures, aimed at quantifying performance measures for comparison with criteria. Note: Assessment should be distinguished from analysis. Assessment is aimed at providing information that forms the basis for deciding whether or not something is satisfactory. Various kinds of analysis may be used as tools when making an assessment; therefore, an assessment may include a number of analyses.

atom (atome)

The smallest particle of an element that cannot be divided or broken up by chemical means. The atom consists of a central core (or nucleus), containing protons and neutrons, with electrons revolving in orbits in the region surrounding the nucleus.

at power (exploitation normale)

An operational state characterized by the following conditions:

  • the reactor being critical
  • automatic actuation of safety systems not blocked
  • essential support systems aligned in their normal power configuration
authority having jurisdiction (AHJ) (autorité compétente (AC))

The regulatory organization, office or agency responsible for approving or accepting designs, equipment, materials, installations or procedures in accordance with applicable codes and standards.

Note 1: In Canada, the regulatory authorities are the Canadian Nuclear Safety Commission (CNSC) and other provincial or federal government agencies that have jurisdiction.

Note 2: the authority having jurisdiction is also referred to as the “regulatory authority”.

authorized access (accès autorisé)

Access that is granted in writing by the licensee.

authorized health physicist (spécialiste principal en radioprotection)

See senior health physicist.

authorized inspection agency (agence d’inspection autorisée)

With respect to pressure boundaries, an organization designated by the authority having jurisdiction, as authorized to register designs and procedures, perform inspections, and perform other defined functions for pressure-retaining components.

authorized nuclear operator (ANO) (opérateur nucléaire autorisé [ONA])

See reactor operator.

availability (disponibilité)

The fraction of time that a component or system is able to function. Availability can also mean the probability that a component or system will be able to function at any given time.

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