1The term ‘facilities and activities’ is defined in SF-1 [2] and in the IAEA Safety Glossary [4]. It is a general term encompassing all nuclear facilities and uses of all sources of ionizing radiation. The recommendations of this Safety Guide apply to certain facilities and activities, as described in paras 1.10–1.24.

2An explanation of the term ‘governmental decision making process’ is provided in para. 2.3.

3The IAEA has also issued a Safety Report on methods and models that can be used to assess the impact of releases of radioactive material to the environment [10] and Technical Reports relevant to environmental transfer parameters [11, 12]. A revision of Safety Reports Series No. 19 [10] is in preparation and will cover screening assessments of public exposure, generic models and parameters for use in assessing the impact of radioactive discharges, and generic models and parameters for assessing exposures of flora and fauna due to radioactive discharges from facilities and activities.

4GSR Part 3 [1] uses the term ‘interested party’ to mean, in a broad sense, a person or group having an interest in the performance of an organization. Interested parties have typically included customers, owners, operators, employees, suppliers, partners and trade unions; the regulated industry or professionals; scientific bodies; and governmental agencies or regulatory bodies. The term could also include other States (e.g. neighbouring States concerned with possible transboundary impacts).

5 Facilities and activities needing a radiological environmental impact assessment are those in which radioactive material is produced, processed, used, handled or stored in such a form and on such a scale that consideration of the possible impact on the public and the environment is required. Examples of such facilities include nuclear installations (including nuclear power plants, research reactors, radioisotope production facilities, source production facilities, spent fuel storage facilities, reprocessing facilities, facilities for the enrichment of uranium, nuclear fuel fabrication facilities, predisposal radioactive waste management facilities, disposal facilities during the operational period, and nuclear fuel cycle related research and development facilities); some mining and raw material processing facilities, such as open pit uranium mines; and facilities for the milling or processing of uranium ores. Examples of activities include the use of unsealed radiation sources for industrial, research and medical purposes, and the decommissioning of certain facilities.

6‘Safety analysis’ is part of the safety assessment for facilities and activities [5].

7The IAEA Safety Glossary defines an ‘accident’ as “Any unintended event, including operating errors, equipment failures and other mishaps, the consequences or potential consequences of which are not negligible from the point of view of protection and safety” (italic denotes a term with an entry in the Safety Glossary) [4].

8Monitoring programmes at the pre-operational stage are defined, for instance, to establish ‘baseline’ activity concentrations in environmental media and to provide information and data for dose assessment purposes [18]. During the operation of the facility or the conduct of the activity, monitoring programmes are put in place to verify compliance with discharge limits, to check the conditions of operation, to provide warning of unusual or unforeseen conditions and to check the predictions of environmental models [18].

9 The term ‘governmental decision making process’ encompasses or is related to different terms used in some States with similar or equivalent meanings, such as ‘decision in principle’, ‘environmental impact statement’, and, in some cases, ‘justification’.

10Reference [31] provides information on environmental impact assessments in the framework of the development of a new nuclear power programme.

11 The principle of dose and risk limitation is not applied to emergency exposure situations and existing exposure situations, for which reference levels are used instead.

12 The consideration of the protection of the public and the environment from possible transboundary impacts and the obligations for assessing the impacts and sharing information between States also needs to be addressed within the broader context of relevant international agreements and conventions (e.g. Espoo 1991 [23], UNCLOS 1982 [24], Aarhus 1998 [25] and Article 37 of the EURATOM Treaty [32]).

13The concept of exemption and the general criteria for exemption of practices are set out in Schedule I of GSR Part 3 [1].

14The ‘source term’ is “The amount and isotopic composition of radioactive material released (or postulated to be released) from a facility” [4]. The concept is used in modelling releases of radionuclides to the environment. It is also applicable to certain activities and, together with the physical and chemical properties of the material released, can be relevant for modelling environmental dispersion.

15Some international directives, such as the Convention on Environmental Impact Assessment in a Transboundary Context [23] and Directive 2011/92/EU on the Assessment of the Effects of Certain Public and Private Projects on the Environment [26], specify the types of facility and activity for which an environmental impact assessment is necessary.

16 Environmental compartments are, for example, air, water, sediment and biota.

17There exist a number of ‘state of the art’ models applicable to radiological environmental impact assessment that have been developed and used by various States and, in some cases, provided by commercial companies. The IAEA regularly conducts international projects for the validation of models and data, in which some of these models are used in test cases and for benchmarking. Information on models applied within the IAEA’s Environmental Modelling for Radiation Safety (EMRAS) programme can be found in Ref. [38]; reports on models applied within the EMRAS II and Modelling and Data for Radiological Impact Assessments (MODARIA) programmes are in preparation.

18 The concept and the characteristics of the representative person for normal operation are set out in paras 5.32–5.35.

19 Compartmental models are models used to represent different transfer processes between the compartments of a system, with each compartment assumed to be a homogeneous entity.

20Workers exposed to radiation from sources that are not directly related to their work are required to be provided with the same level of protection as members of the public (see para. 3.78 of GSR Part 3 [1]). Consequently, for the purposes of the radiological environmental impact assessment, such workers on the site are considered as members of the public.

21The concept of representative person is defined by the ICRP for radiation protection purposes. GSR Part 3 [1] defines the representative person as “An individual receiving a dose that is representative of the doses to the more highly exposed individuals in the population.” The representative person is not an actual member of the population but is rather a reference individual defined using dosimetric models and habit data characteristic of those individuals more highly exposed and is used in determinations of compliance or in prospective assessments. The representative person to be used for the purpose of the assessment and control of exposures due to discharges in normal operation is defined in the national legislation or regulations of some States.

22 The ‘committed dose’ is the lifetime dose expected to result from an intake. Further information is provided in previous IAEA guidance: INTERNATIONAL ATOMIC ENERGY AGENCY, Principles for Limiting Releases of Radioactive Effluents into the Environment, IAEA Safety Series No. 77, IAEA, Vienna (1986).

23 The concept of ‘a measure of the risk of health effects’ due to exposure to radiation resulting from postulated accidents is explained in more detail in Annex II.

24In this Safety Guide, the expression ‘potential exposure scenarios’ includes the characteristics of all the events or sequences of events that may lead to an accident, including their source term characteristics and, when applicable, their frequency of occurrence or probability.

25 ‘Characteristic accident source terms’ are source terms that can be considered to be a comprehensive representation of the characteristics of the specific facility or activity under accident conditions. The accident source terms identified as characteristic of the facility or activity can be divided into different categories in accordance with their annual frequency or likelihood of occurrence and their magnitude. Characteristic accident source terms do not necessarily include the worst case scenario, which is typically a very cautious assumption involving estimates of unrealistic potential consequences. For further information see Annex II.

26The ICRP uses the term ‘representative person’ for the consideration of both normal discharges and accidental releases [44]. Despite the use of the same term and the applicability of the general definition to both situations, the particular characteristics of the representative person in each case, such as his or her location, habits and age group, may be different.

27The IAEA Safety Glossary [4] defines ‘end point’ as “A radiological or other measure of protection or safety that is the calculated result of an analysis or assessment.” Common end points include estimates of dose or risk and predicted environmental concentrations of radionuclides.

28 Paragraph 3.15 of GSR Part 3 [1] additionally states that the number of individuals who may be affected by potential exposures is required to be assessed; however, the scope of this Safety Guide is limited to effects on individuals.

29This approach is consistent with the IAEA requirements for design of nuclear power plants for accidents with significant off-site consequences, for which only protective actions that are limited in terms of lengths of time and areas of application would be acceptable and off-site contamination would be avoided or minimized [47].

30 For example, the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter [55] requires the explicit assessment of the radiological impact on marine flora and fauna resulting from the dumping of materials containing radionuclides. The IAEA has developed a radiological assessment procedure for this purpose [56].

31Potential exposures of flora and fauna are not taken into account, since those are not amenable to regulatory control under accident conditions.

1 With regard to the need for reference models to represent typical farm animals — primarily large mammals that live essentially in a human environment — for the purpose of their protection, the ICRP considered that the use of an assessment of the radiological impact on humans was sufficient for such managed environmental or ecological situations [I–1].

2A ‘reference animal or plant’ is a hypothetical entity with the assumed basic biological characteristics of a particular type of animal or plant, as described to the generality of the taxonomic level of family, with defined anatomical, physiological and life history properties that can be used for the purposes of relating exposures to dose, and dose to effects, for that type of living organism [I–1, I–2].

3The combination of radiation weighting factors with tissue weighting factors for estimating effective doses to humans, expressed in sieverts (Sv), is not applied in assessing the risk of effects due to exposure of biota; the key quantity used for the assessment of the effects of exposure of biota is the absorbed dose, which is defined as the amount of energy that is absorbed by a unit mass of tissue of an organ or organism, given in units of joules per kilogram or grays (Gy), and which depends on the amount and type of radiation [I–1]. Owing to the consideration of different species of flora and fauna with different lifespans, it is convenient to express the criteria in terms of a dose rate, in grays per day (Gy/d) or its subunits, for instance milligrays per day (mGy/d) [I–1, I–8].

4 The transfer parameters used to estimate exposures of humans due to the ingestion of biota as part of their diet, such as fish, are different from the transfer factors used to estimate exposures of biota, such as fish themselves. The former consider only the activity concentration in the edible part of the fish, while the latter consider the activity concentration in the full fish, including in the bones.

5A revision of Safety Reports Series No. 19 [I–9] is in preparation and will cover screening assessments of public exposure, generic models and parameters for use in assessing the impact of radioactive discharges, and generic models and parameters for assessing exposures of flora and fauna due to radioactive discharges from facilities and activities.

6A different but equivalent set of reference organisms is recommended by the European Commission’s Environmental Risk from Ionising Contaminants: Assessment and Management (ERICA) project [I–4].

7This area could be either a circle of about 5–10 km radius or a box with 10–20 km sides, both centred on the release point.

8The revision in preparation of Ref. [I–9] will provide practical methods for estimating dose rates to representative animals and plants using generic environmental dispersion scenarios and the dosimetric factors set out in Ref. [I–1].

9Some States have defined and used different approaches to assessing the radiological impact to flora and fauna, including their own radiological criteria, which are generally compatible with the ICRP approach and derived consideration reference levels [I–3 to I–5].

1 The definitions of ‘risk’ presented in this annex can only be interpreted as giving an indication of the risks, owing to the many uncertainties involved in a probabilistic safety analysis, in the estimation of the possible exposures and in the quantification of the associated radiological consequences. See also INTERNATIONAL ATOMIC ENERGY AGENCY, Extension of the Principles of Radiation Protection to Sources of Potential Exposure, Safety Series No. 104, IAEA, Vienna (1990).

2To be more precise, the probability of the health effect can be estimated using the dose response function, f(D), which changes with the level of dose. The risk of early health effects can also be calculated using hazard functions, by taking into account the variation of risk with the rate at which the dose is accumulated over a certain period (e.g. the first day or few days following the accident). The risk of late health effects can take into account not only fatal but also non-fatal cancers in different organs, leukaemia and heritable effects. The details of these considerations are out of the scope of this annex.