IAEA Safety Standards. Radiation Protection of the Public and the Environment

Transcription

1 IAEA Safety Standards for protecting people and the environment Radiation Protection of the Public and the Environment Jointly sponsored by General Safety Guide No. GSG-8

2 IAEA SAFETY STANDARDS AND RELATED PUBLICATIONS IAEA SAFETY STANDARDS Under the terms of Article III of its Statute, the IAEA is authorized to establish or adopt standards of safety for protection of health and minimization of danger to life and property, and to provide for the application of these standards. The publications by means of which the IAEA establishes standards are issued in the IAEA Safety Standards Series. This series covers nuclear safety, radiation safety, transport safety and waste safety. The publication categories in the series are Safety Fundamentals, Safety Requirements and Safety Guides. Information on the IAEA s safety standards programme is available on the IAEA Internet site The site provides the texts in English of published and draft safety standards. The texts of safety standards issued in Arabic, Chinese, French, Russian and Spanish, the IAEA Safety Glossary and a status report for safety standards under development are also available. For further information, please contact the IAEA at: Vienna International Centre, PO Box 100, 1400 Vienna, Austria. All users of IAEA safety standards are invited to inform the IAEA of experience in their use (e.g. as a basis for national regulations, for safety reviews and for training courses) for the purpose of ensuring that they continue to meet users needs. Information may be provided via the IAEA Internet site or by post, as above, or by to Official.Mail@iaea.org. RELATED PUBLICATIONS The IAEA provides for the application of the standards and, under the terms of Articles III and VIII.C of its Statute, makes available and fosters the exchange of information relating to peaceful nuclear activities and serves as an intermediary among its Member States for this purpose. Reports on safety in nuclear activities are issued as Safety Reports, which provide practical examples and detailed methods that can be used in support of the safety standards. Other safety related IAEA publications are issued as Emergency Preparedness and Response publications, Radiological Assessment Reports, the International Nuclear Safety Group s INSAG Reports, Technical Reports and TECDOCs. The IAEA also issues reports on radiological accidents, training manuals and practical manuals, and other special safety related publications. Security related publications are issued in the IAEA Nuclear Security Series. The IAEA Nuclear Energy Series comprises informational publications to encourage and assist research on, and the development and practical application of, nuclear energy for peaceful purposes. It includes reports and guides on the status of and advances in technology, and on experience, good practices and practical examples in the areas of nuclear power, the nuclear fuel cycle, radioactive waste management and decommissioning.

3 RADIATION PROTECTION OF THE PUBLIC AND THE ENVIRONMENT

4 The Agency s Statute was approved on 23 October 1956 by the Conference on the Statute of the IAEA held at United Nations Headquarters, New York; it entered into force on 29 July The Headquarters of the Agency are situated in Vienna. Its principal objective is to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world.

5 IAEA SAFETY STANDARDS SERIES No. GSG-8 RADIATION PROTECTION OF THE PUBLIC AND THE ENVIRONMENT GENERAL SAFETY GUIDE JOINTLY SPONSORED BY THE INTERNATIONAL ATOMIC ENERGY AGENCY AND UNITED NATIONS ENVIRONMENT PROGRAMME INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA, 2018

6 COPYRIGHT NOTICE All IAEA scientific and technical publications are protected by the terms of the Universal Copyright Convention as adopted in 1952 (Berne) and as revised in 1972 (Paris). The copyright has since been extended by the World Intellectual Property Organization (Geneva) to include electronic and virtual intellectual property. Permission to use whole or parts of texts contained in IAEA publications in printed or electronic form must be obtained and is usually subject to royalty agreements. Proposals for non-commercial reproductions and translations are welcomed and considered on a case-by-case basis. Enquiries should be addressed to the IAEA Publishing Section at: Marketing and Sales Unit, Publishing Section International Atomic Energy Agency Vienna International Centre PO Box Vienna, Austria fax: tel.: sales.publications@iaea.org IAEA, 2018 Printed by the IAEA in Austria May 2018 STI/PUB/1781 IAEA Library Cataloguing in Publication Data Names: International Atomic Energy Agency. Title: Radiation protection of the public and the environment / International Atomic Energy Agency. Description: Vienna : International Atomic Energy Agency, Series: IAEA safety standards series, ISSN X ; no. GSG-8 Includes bibliographical references. Identifiers: IAEAL ISBN (paperback : alk. paper) Subjects: LCSH: Radiation Safety measures. Ionizing radiation Safety measures. Radiation Measurement. Classification: UDC STI/PUB/1781

7 FOREWORD by Yukiya Amano Director General The IAEA s Statute authorizes the Agency to establish or adopt standards of safety for protection of health and minimization of danger to life and property standards that the IAEA must use in its own operations, and which States can apply by means of their regulatory provisions for nuclear and radiation safety. The IAEA does this in consultation with the competent organs of the United Nations and with the specialized agencies concerned. A comprehensive set of high quality standards under regular review is a key element of a stable and sustainable global safety regime, as is the IAEA s assistance in their application. The IAEA commenced its safety standards programme in The emphasis placed on quality, fitness for purpose and continuous improvement has led to the widespread use of the IAEA standards throughout the world. The Safety Standards Series now includes unified Fundamental Safety Principles, which represent an international consensus on what must constitute a high level of protection and safety. With the strong support of the Commission on Safety Standards, the IAEA is working to promote the global acceptance and use of its standards. Standards are only effective if they are properly applied in practice. The IAEA s safety services encompass design, siting and engineering safety, operational safety, radiation safety, safe transport of radioactive material and safe management of radioactive waste, as well as governmental organization, regulatory matters and safety culture in organizations. These safety services assist Member States in the application of the standards and enable valuable experience and insights to be shared. Regulating safety is a national responsibility, and many States have decided to adopt the IAEA s standards for use in their national regulations. For parties to the various international safety conventions, IAEA standards provide a consistent, reliable means of ensuring the effective fulfilment of obligations under the conventions. The standards are also applied by regulatory bodies and operators around the world to enhance safety in nuclear power generation and in nuclear applications in medicine, industry, agriculture and research. Safety is not an end in itself but a prerequisite for the purpose of the protection of people in all States and of the environment now and in the future. The risks associated with ionizing radiation must be assessed and controlled without unduly limiting the contribution of nuclear energy to equitable and sustainable development. Governments, regulatory bodies and operators everywhere must ensure that nuclear material and radiation sources are used beneficially, safely and ethically. The IAEA safety standards are designed to facilitate this, and I encourage all Member States to make use of them.

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9 PREFACE Requirements for the protection of people from harmful consequences of exposure to ionizing radiation, for the safety of radiation sources and for protection of the environment are established in the IAEA Safety Requirements for Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards (IAEA Safety Standards Series No. GSR Part 3). GSR Part 3 is jointly sponsored by the European Commission, the Food and Agriculture Organization of the United Nations, the IAEA, the International Labour Organization, the OECD Nuclear Energy Agency, the Pan American Health Organization, the United Nations Environment Programme and the World Health Organization. Three related Safety Guides were prepared to provide generic guidance on meeting the requirements of GSR Part 3 for protection of the public and protection of the environment, as follows: IAEA Safety Standards Series No. GSG-8, Radiation Protection of the Public and the Environment, which provides guidance on the framework for protection for the public and the environment; IAEA Safety Standards Series No. GSG-9, Regulatory Control of Discharges to the Environment, which provides guidance on application of the principles of radiation protection and the safety objectives associated with the control of discharges and on the process for authorization of discharges; IAEA Safety Standards Series No. GSG-10, Prospective Radiological Environmental Impact Assessment for Facilities and Activities, which describes a framework and methodologies for prospective radiological environmental impact assessment. These three Safety Guides are jointly sponsored by the IAEA and UN Environment, the leading global environmental authority, which sets the global environmental agenda, promotes the coherent implementation of the environmental dimension of sustainable development within the United Nations system, and serves as an authoritative advocate for the global environment. The recommendations provided in these three Safety Guides, together with the requirements of GSR Part 3, provide a basis for including environmental considerations in the assessment and management of radioactive releases. In this context, UN Environment encourages the application of these recommendations in all its Member States, and their use as a foundation for the development of national regulations on protection of the environment from harmful effects of ionizing radiation.

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11 THE IAEA SAFETY STANDARDS BACKGROUND Radioactivity is a natural phenomenon and natural sources of radiation are features of the environment. Radiation and radioactive substances have many beneficial applications, ranging from power generation to uses in medicine, industry and agriculture. The radiation risks to workers and the public and to the environment that may arise from these applications have to be assessed and, if necessary, controlled. Activities such as the medical uses of radiation, the operation of nuclear installations, the production, transport and use of radioactive material, and the management of radioactive waste must therefore be subject to standards of safety. Regulating safety is a national responsibility. However, radiation risks may transcend national borders, and international cooperation serves to promote and enhance safety globally by exchanging experience and by improving capabilities to control hazards, to prevent accidents, to respond to emergencies and to mitigate any harmful consequences. States have an obligation of diligence and duty of care, and are expected to fulfil their national and international undertakings and obligations. International safety standards provide support for States in meeting their obligations under general principles of international law, such as those relating to environmental protection. International safety standards also promote and assure confidence in safety and facilitate international commerce and trade. A global nuclear safety regime is in place and is being continuously improved. IAEA safety standards, which support the implementation of binding international instruments and national safety infrastructures, are a cornerstone of this global regime. The IAEA safety standards constitute a useful tool for contracting parties to assess their performance under these international conventions. THE IAEA SAFETY STANDARDS The status of the IAEA safety standards derives from the IAEA s Statute, which authorizes the IAEA to establish or adopt, in consultation and, where appropriate, in collaboration with the competent organs of the United Nations and with the specialized agencies concerned, standards of safety for protection of health and minimization of danger to life and property, and to provide for their application.

12 With a view to ensuring the protection of people and the environment from harmful effects of ionizing radiation, the IAEA safety standards establish fundamental safety principles, requirements and measures to control the radiation exposure of people and the release of radioactive material to the environment, to restrict the likelihood of events that might lead to a loss of control over a nuclear reactor core, nuclear chain reaction, radioactive source or any other source of radiation, and to mitigate the consequences of such events if they were to occur. The standards apply to facilities and activities that give rise to radiation risks, including nuclear installations, the use of radiation and radioactive sources, the transport of radioactive material and the management of radioactive waste. Safety measures and security measures 1 have in common the aim of protecting human life and health and the environment. Safety measures and security measures must be designed and implemented in an integrated manner so that security measures do not compromise safety and safety measures do not compromise security. The IAEA safety standards reflect an international consensus on what constitutes a high level of safety for protecting people and the environment from harmful effects of ionizing radiation. They are issued in the IAEA Safety Standards Series, which has three categories (see Fig. 1). Safety Fundamentals Safety Fundamentals present the fundamental safety objective and principles of protection and safety, and provide the basis for the safety requirements. Safety Requirements An integrated and consistent set of Safety Requirements establishes the requirements that must be met to ensure the protection of people and the environment, both now and in the future. The requirements are governed by the objective and principles of the Safety Fundamentals. If the requirements are not met, measures must be taken to reach or restore the required level of safety. The format and style of the requirements facilitate their use for the establishment, in a harmonized manner, of a national regulatory framework. Requirements, including numbered overarching requirements, are expressed as shall statements. Many requirements are not addressed to a specific party, the implication being that the appropriate parties are responsible for fulfilling them. 1 See also publications issued in the IAEA Nuclear Security Series.

13 Safety Fundamentals Fundamental Safety Principles General Safety Requirements Part 1. Governmental, Legal and Regulatory Framework for Safety Part 2. Leadership and Management for Safety Part 3. Radiation Protection and Safety of Radiation Sources Part 4. Safety Assessment for Facilities and Activities Part 5. Predisposal Management of Radioactive Waste Part 6. Decommissioning and Termination of Activities Part 7. Emergency Preparedness and Response Specific Safety Requirements 1. Site Evaluation for Nuclear Installations 2. Safety of Nuclear Power Plants 2/1 Design 2/2 Commissioning and Operation 3. Safety of Research Reactors 4. Safety of Nuclear Fuel Cycle Facilities 5. Safety of Radioactive Waste Disposal Facilities 6. Safe Transport of Radioactive Material Collection of Safety Guides FIG. 1. The long term structure of the IAEA Safety Standards Series. Safety Guides Safety Guides provide recommendations and guidance on how to comply with the safety requirements, indicating an international consensus that it is necessary to take the measures recommended (or equivalent alternative measures). The Safety Guides present international good practices, and increasingly they reflect best practices, to help users striving to achieve high levels of safety. The recommendations provided in Safety Guides are expressed as should statements. APPLICATION OF THE IAEA SAFETY STANDARDS The principal users of safety standards in IAEA Member States are regulatory bodies and other relevant national authorities. The IAEA safety standards are also used by co-sponsoring organizations and by many organizations that design, construct and operate nuclear facilities, as well as organizations involved in the use of radiation and radioactive sources.

14 The IAEA safety standards are applicable, as relevant, throughout the entire lifetime of all facilities and activities existing and new utilized for peaceful purposes and to protective actions to reduce existing radiation risks. They can be used by States as a reference for their national regulations in respect of facilities and activities. The IAEA s Statute makes the safety standards binding on the IAEA in relation to its own operations and also on States in relation to IAEA assisted operations. The IAEA safety standards also form the basis for the IAEA s safety review services, and they are used by the IAEA in support of competence building, including the development of educational curricula and training courses. International conventions contain requirements similar to those in the IAEA safety standards and make them binding on contracting parties. The IAEA safety standards, supplemented by international conventions, industry standards and detailed national requirements, establish a consistent basis for protecting people and the environment. There will also be some special aspects of safety that need to be assessed at the national level. For example, many of the IAEA safety standards, in particular those addressing aspects of safety in planning or design, are intended to apply primarily to new facilities and activities. The requirements established in the IAEA safety standards might not be fully met at some existing facilities that were built to earlier standards. The way in which IAEA safety standards are to be applied to such facilities is a decision for individual States. The scientific considerations underlying the IAEA safety standards provide an objective basis for decisions concerning safety; however, decision makers must also make informed judgements and must determine how best to balance the benefits of an action or an activity against the associated radiation risks and any other detrimental impacts to which it gives rise. DEVELOPMENT PROCESS FOR THE IAEA SAFETY STANDARDS The preparation and review of the safety standards involves the IAEA Secretariat and five safety standards committees, for emergency preparedness and response (EPReSC) (as of 2016), nuclear safety (NUSSC), radiation safety (RASSC), the safety of radioactive waste (WASSC) and the safe transport of radioactive material (TRANSSC), and a Commission on Safety Standards (CSS) which oversees the IAEA safety standards programme (see Fig. 2). All IAEA Member States may nominate experts for the safety standards committees and may provide comments on draft standards. The membership of

15 Outline and work plan prepared by the Secretariat; review by the safety standards committees and the CSS Secretariat and consultants: drafting of new or revision of existing safety standard Draft Review by safety standards committee(s) Final draft Draft Comments Member States Endorsement by the CSS FIG. 2. The process for developing a new safety standard or revising an existing standard. the Commission on Safety Standards is appointed by the Director General and includes senior governmental officials having responsibility for establishing national standards. A management system has been established for the processes of planning, developing, reviewing, revising and establishing the IAEA safety standards. It articulates the mandate of the IAEA, the vision for the future application of the safety standards, policies and strategies, and corresponding functions and responsibilities. INTERACTION WITH OTHER INTERNATIONAL ORGANIZATIONS The findings of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and the recommendations of international

16 expert bodies, notably the International Commission on Radiological Protection (ICRP), are taken into account in developing the IAEA safety standards. Some safety standards are developed in cooperation with other bodies in the United Nations system or other specialized agencies, including the Food and Agriculture Organization of the United Nations, the United Nations Environment Programme, the International Labour Organization, the OECD Nuclear Energy Agency, the Pan American Health Organization and the World Health Organization. INTERPRETATION OF THE TEXT Safety related terms are to be understood as defined in the IAEA Safety Glossary (see Otherwise, words are used with the spellings and meanings assigned to them in the latest edition of The Concise Oxford Dictionary. For Safety Guides, the English version of the text is the authoritative version. The background and context of each standard in the IAEA Safety Standards Series and its objective, scope and structure are explained in Section 1, Introduction, of each publication. Material for which there is no appropriate place in the body text (e.g. material that is subsidiary to or separate from the body text, is included in support of statements in the body text, or describes methods of calculation, procedures or limits and conditions) may be presented in appendices or annexes. An appendix, if included, is considered to form an integral part of the safety standard. Material in an appendix has the same status as the body text, and the IAEA assumes authorship of it. Annexes and footnotes to the main text, if included, are used to provide practical examples or additional information or explanation. Annexes and footnotes are not integral parts of the main text. Annex material published by the IAEA is not necessarily issued under its authorship; material under other authorship may be presented in annexes to the safety standards. Extraneous material presented in annexes is excerpted and adapted as necessary to be generally useful.

17 CONTENTS 1. INTRODUCTION... 1 Background ( ) Objective (1.7)... 2 Scope ( ) Structure (1.11) FRAMEWORK FOR THE PROTECTION OF THE PUBLIC AND THE ENVIRONMENT Introduction ( ) Exposure situations ( )... 4 Radiation protection principles ( ) Responsibilities ( ) Graded approach ( ) RADIATION PROTECTION OF THE PUBLIC Planned exposure situations ( ) Emergency exposure situations ( ) Existing exposure situations ( ) PROTECTION OF THE ENVIRONMENT ( ) APPENDIX: DOSE CONSTRAINTS AND REFERENCE LEVELS REFERENCES CONTRIBUTORS TO DRAFTING AND REVIEW... 51

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19 1. INTRODUCTION BACKGROUND 1.1. The fundamental safety objective established in IAEA Safety Standards Series No. SF-1, Fundamental Safety Principles [1], is to protect people and the environment from harmful effects of ionizing radiation. It applies to all circumstances that give rise to radiation risks. The fundamental safety objective is associated with ten safety principles [1]. Virtually all of these safety principles touch on the protection of members of the public and the environment. Principle 7 in particular states that: People and the environment, present and future, must be protected against radiation risks General requirements designed to protect members of the public and the environment from harmful effects of ionizing radiation are established in IAEA Safety Standards Series No. GSR Part 3, Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards [2]. The requirements for the governmental, legal and regulatory framework to be used are established in IAEA Safety Standards Series No. GSR Part 1 (Rev. 1), Governmental, Legal and Regulatory Framework for Safety [3]. The requirements for emergency preparedness and response are established in IAEA Safety Standards Series No. GSR Part 7, Preparedness and Response for a Nuclear or Radiological Emergency [4] Radiation protection has been largely focused on the protection of humans and, for this purpose, three basic categories of exposure have been considered, namely occupational exposure, medical exposure and public exposure. The relevant radiation protection requirements are defined according to the exposure situation, namely planned exposure situations, emergency exposure situations and existing exposure situations Public exposure is defined as exposure incurred by members of the public due to sources in planned exposure situations, emergency exposure situations and existing exposure situations, excluding any occupational exposure or medical exposure [2]. GSR Part 3 [2] defines a member of the public as any individual in the population except when subject to occupational exposure or medical exposure. For the purpose of verifying compliance with the annual dose limit for public exposure, this is the representative person. GSR Part 3 [2] defines a representative person as an individual receiving a dose that is representative of the doses to the more highly exposed individuals in the population. 1

20 1.5. In recent years, consideration has also been given to the protection of the environment. As noted by the International Commission on Radiological Protection (ICRP) [5 7], some national regulatory frameworks have already addressed the need to be able to demonstrate that the environment is protected against harmful effects of ionizing radiation, irrespective of any human connection with the environment. The methods and criteria for radiological assessments are being developed and will continue to evolve This Safety Guide provides generic guidance on the application of the requirements of GSR Part 3 [2] and GSR Part 7 [4] in relation to the protection of members of the public in planned exposure situations, existing exposure situations and emergency exposure situations and protection of the environment that is applicable for all facilities and activities. OBJECTIVE 1.7. The objective of this Safety Guide is to provide generic guidance on the application of the requirements for the protection of members of the public against radiation exposure and protection of the environment established in GSR Part 3 [2] and GSR Part 7 [4]. It is intended for use by: (a) (b) (c) (d) Governments; Regulatory bodies; Registrants and licensees, or the person or organization responsible for facilities and activities for which notification only is required in planned exposure situations; Those persons or organizations designated to deal with emergency exposure situations or existing exposure situations. SCOPE 1.8. This Safety Guide covers the generic application of the requirements given in GSR Part 3 [2] that relate to the protection of the environment and protection of members of the public in planned exposure situations and existing exposure situations and in GSR Part 3 [2] and GSR Part 7 [4] in emergency exposure situations. 2

21 1.9. This Safety Guide does not deal with the application of the requirements in GSR Part 3 [2] to specific types of facility or activity or in specific exposure situations. In this context, separate Safety Guides exist or are under development, such as: For planned exposure situations: IAEA Safety Standards Series No. GSG-5, Justification of Practices, Including Non-Medical Human Imaging [8]; IAEA Safety Standards Series No. GSG-10, Prospective Radiological Environmental Impact Assessment for Facilities and Activities [9]; IAEA Safety Standards Series No. GSG-9, Regulatory Control of Radioactive Discharges to the Environment [10]; IAEA Safety Standards Series No. SSG-36, Radiation Safety for Consumer Products [11]; For emergency exposure situations: IAEA Safety Standards Series No. GSG-2, Criteria for Use in Preparedness and Response for a Nuclear or Radiological Emergency [12]; IAEA Safety Standards Series No. GS-G-2.1, Arrangements for Preparedness for a Nuclear or Radiological Emergency [13]; For existing exposure situations: IAEA Safety Standards Series No. WS-G-3.1, Remediation Process for Areas Affected by Past Activities and Accidents [14]; IAEA Safety Standards Series No. SSG-32, Protection of the Public against Exposure Indoors due to Radon and Other Natural Sources of Radiation [15] Occupational exposure and medical exposure are not considered in this Safety Guide; the relevant recommendations are provided in IAEA Safety Standards Series No. GSG-7, Occupational Radiation Protection [16] and in IAEA Safety Standards Series No. SSG-46, Radiation Protection and Safety in Medical Uses of Ionizing Radiation [17]. STRUCTURE Section 2 provides an overview of the basic framework for radiation protection of members of the public and protection of the environment in planned exposure situations, emergency exposure situations and existing exposure situations. It covers the principles of justification, optimization of protection and dose limits, where appropriate. Section 3 deals with the practical application of the 3

22 radiation protection framework for protection of the public in planned exposure situations, emergency exposure situations and existing exposure situations. Section 4 provides guidance on meeting the requirements of GSR Part 3 [2] for protection of the environment. The Appendix summarizes the framework for dose constraints and reference levels as applicable for each exposure situation, in accordance with GSR Part 3 [2]. 2. FRAMEWORK FOR THE PROTECTION OF THE PUBLIC AND PROTECTION OF THE ENVIRONMENT INTRODUCTION 2.1. Paragraph 2.15 of GSR Part 3 [2] requires the scope of applicability of the legal and regulatory framework to be specified. The regulatory framework established in GSR Part 3 [2] applies to all situations involving radiation exposure that is amenable to control. Exposures that are deemed to be unamenable to control are excluded from the regulatory framework. Examples of exposures that are unamenable to control are 40 K in the body and cosmic radiation at the surface of the Earth GSR Part 3 [2] establishes requirements for each of the three exposure situations: planned exposure situations, emergency exposure situations and existing exposure situations. In addition, in the context of emergency exposure situations, GSR Part 7 [4] establishes requirements for an adequate level of preparedness and response for a nuclear or radiological emergency. EXPOSURE SITUATIONS Planned exposure situations 2.3. A planned exposure situation is a situation of exposure that arises from the planned operation of a source or from a planned activity that results in an exposure due to a source. Since provision for protection and safety can be made before embarking on the activity concerned, the associated exposures and their likelihood of occurrence can be restricted from the outset. The primary means 4

23 of controlling exposure in planned exposure situations is by good design of facilities, equipment and operating procedures, by training and by fostering safety culture [2, 18] In planned exposure situations, exposure at some level can be expected to occur. If exposure is not expected to occur with certainty, but could result from an anticipated operational occurrence or accident or owing to an event or a sequence of events that may potentially occur but is not certain to occur, this is referred to as potential exposure. The magnitude and extent of potential exposure can usually be predicted. Both exposures expected to occur and potential exposures can and should be taken into account at the planning or design stage A term closely related to planned exposure situation is the term practice, which is defined as any human activity that introduces additional sources of radiation or additional exposure pathways, or that modifies the network of exposure pathways from existing sources, so as to increase the exposure or the likelihood of exposure of people or the number of people exposed [19]. Both terms are used in GSR Part 3 [2], although the term planned exposure situation emphasizes the planned or intentional nature of the facility or activity that may give rise to radiation exposure. Emergency exposure situations 2.6. An emergency exposure situation is a situation of exposure that arises as a result of an accident, a malicious act or any other unexpected event, and requires prompt action in order to avoid or reduce adverse consequences [2]. Preventive measures and mitigatory actions have to be considered before an emergency exposure situation arises. However, once an emergency exposure situation actually arises, exposures can be reduced only by implementing protective actions. Existing exposure situations 2.7. An existing exposure situation is a situation of exposure that already exists when a decision on the need for control needs to be taken [2]. Existing exposure situations include situations of exposure to natural background radiation. They also include situations of exposure due to residual radioactive material that derives from past practices that were never subject to regulatory control or that were subject to regulatory control but not in accordance with the requirements of current standards, situations of exposure due to residual radioactive material deriving from a nuclear or radiological emergency after an emergency has been 5

24 declared to be ended, and situations of exposure due to commodities incorporating radionuclides from such material. RADIATION PROTECTION PRINCIPLES 2.8. The three basic principles that underpin radiation protection, which concern justification, optimization of protection and safety, and application of dose limits, are expressed in Safety Principles 4, 5, 6 and 10 of SF-1 [1]. The principles of justification and optimization of protection and safety relate to sources of ionizing radiation and apply to all exposure situations. The principle of application of dose limits relates to individuals and applies to public exposure in planned exposure situations only. Requirement 1 of GSR Part 3 [2] requires that those responsible for protection and safety ensure that these principles of radiation protection are applied for all exposure situations. Justification 2.9. Paragraph 2.8 of GSR Part 3 [2] states that For planned exposure situations, each party with responsibilities for protection and safety shall ensure, when relevant requirements apply to that party, that no practice is undertaken unless it is justified Paragraph 2.9 of GSR Part 3 [2] states that: For emergency exposure situations and existing exposure situations, each party with responsibilities for protection and safety shall ensure, when relevant requirements apply to that party, that protective actions or remedial actions are justified and are undertaken in such a way as to achieve the objectives set out in a protection strategy For planned exposure situations, justification is the process of determining whether a practice is, overall, beneficial, i.e. whether the expected benefits to individuals and to society from introducing or continuing the practice outweigh the harm (including radiation detriment) resulting from the practice [19]. The benefits apply to individuals and society as a whole, and include benefits to the environment. Radiation detriment may only be a small part of the total harm. Justification thus goes far beyond the scope of radiation protection, and also involves the consideration of economic, societal and environmental factors [5]. 6

25 2.12. For emergency exposure situations, when considering the justification of proposed protective actions and the overall protection strategy, para of GSR Part 7 [4] states that: Each protective action, in the context of the protection strategy, and the protection strategy itself shall be demonstrated to be justified (i.e. to do more good than harm), with account taken not only of those detriments that are associated with radiation exposure but also of those detriments associated with impacts of the actions taken on public health, the economy, society and the environment Decisions regarding justification should be taken at a sufficiently high governmental level to enable all of the considerations that may be related to the benefits and detriments to be integrated. Thus, while the regulatory body or other national authority concerned with radiation protection should be responsible for evaluating the assessment of the radiation detriment, it may not be in a position to make the justification decision. Any justification decision should therefore always involve a consideration of the radiation doses either to be incurred or to be averted or reduced according to the circumstances. In planned exposure situations, radiation risks from potential exposures are also required to be considered in the justification decision. Optimization of protection and safety Paragraph 2.10 of GSR Part 3 [2] states that For all exposure situations, each party with responsibilities for protection and safety shall ensure, when relevant requirements apply to that party, that protection and safety is optimized In this context protection and safety is optimized means that optimization of protection and safety has been applied and the result of that process has been implemented Optimization of protection and safety is defined as the process for determining what level of protection and safety would result in the magnitude of individual doses, the number of individuals (workers and members of the public) subject to exposure and the likelihood of exposure being as low as reasonably achievable (ALARA), economic and social factors being taken into account [19]. This means that the level of protection would be the best possible under the prevailing circumstances, and will thus not necessarily be the option with the lowest risk or dose. Protection of the environment should also be considered in the process of optimization of protection and safety. 7

26 2.17. Protection and safety should be optimized through an on-going cyclical approach that involves: (a) (b) (c) (d) (e) Evaluation of the exposure situation to identify the need for action; Identification of possible protective actions to keep the exposure as low as reasonably achievable; Selection of the best protective actions under the prevailing circumstances; Implementation of the selected protective actions; Regular review of the exposure situation to evaluate whether the prevailing circumstances necessitate any changes to the selected protective actions For planned exposure situations, Requirement 11 of GSR Part 3 [2] states that The government or the regulatory body shall establish and enforce requirements for the optimization of protection and safety, and registrants and licensees shall ensure that protection and safety is optimized. Paragraph 3.23 of GSR Part 3 [2] requires registrants and licensees to ensure that protection and safety is optimized For emergency exposure situations, Requirement 44 of GSR Part 3 [2] and Requirement 5 of GSR Part 7 [4] require the government to ensure that protection strategies are developed, justified and optimized at the stage for taking protective actions and other response actions effectively. Paragraph 4.31 of GSR Part 7 [4] states further that the government is also required to ensure that the protection strategy is implemented safely and effectively in an emergency response through the implementation of emergency arrangements For existing exposure situations, Requirement 48 of GSR Part 3 [2] requires the government and the regulatory body or other relevant authority to ensure that protection and safety is optimized In all three exposure situations, the processes of justification and optimization should, when possible, include consultation with interested parties, such as community groups, local residents and members of the public. Boundary conditions for optimization Optimization of protection is a prospective, iterative process that examines the available options for protection. Depending upon the circumstances, the process can include the use of a variety of quantitative and qualitative techniques. Optimization should be conducted within a set of boundary conditions on the range of available protection options. These boundary conditions should include 8

27 individual source related values of dose or risk that may be regarded as values that should not be exceeded for planning purposes. They are referred to as dose constraints or risk constraints in the case of planned exposure situations and as reference levels in the case of emergency exposure situations or existing exposure situations A constraint is a prospective and source related value of individual dose (dose constraint) or risk (risk constraint) that is used in planned exposure situations as a parameter for the optimization of protection and safety for the source, and that serves as a boundary condition in defining the range of options in optimization A dose constraint is a level of dose above which it is unlikely that protection is optimized. It represents a basic level of protection and will always be lower than the pertinent dose limit. However, treating a dose constraint as a target value is not sufficient, and it is expected that optimization of protection will establish an acceptable level of dose below the dose constraint Risk constraints correspond to dose constraints but apply to potential exposure. A risk constraint is a source related value that provides a basic level of protection for the individuals most at risk from a source. This risk is a function of the probability of an unintended event causing a dose and the probability of the detriment due to such a dose. The risk constraint should equate to a similar health risk to that implied by the corresponding dose constraints for the same source [5, 20]. However, there can be large uncertainties in estimations of the probabilities and the resulting dose, which should be taken into account at the time of defining and using the risk constraints for decision making or decision aiding Reference level is defined as, for an emergency exposure situation or an existing exposure situation, the level of dose, risk or activity concentration above which it is not appropriate to plan to allow exposures to occur and below which optimization of protection and safety would continue to be implemented [19]. The value chosen for a reference level will depend upon the prevailing circumstances for the exposure under consideration. In practice, reference levels for some situations are likely to be established on the basis of one or more exposure scenarios. As such, the chosen reference levels are dependent on the assumptions used in their determination, and may not be universally applicable In an emergency exposure situation or in an existing exposure situation, actual exposures could be above or below the reference level. The reference level 9

28 should then be used as a benchmark for judging the extent to which protective actions are necessary and to assist in prioritizing their application. Optimization of protection and safety is to be applied even if the initial estimates of the doses received are below the defined reference levels, if justified and optimized actions are available to reduce exposures. Further recommendations on the application of the concept of the reference level in an emergency exposure situation for dosimetric purposes, in addition to the use of generic criteria, are given in Section In an emergency exposure situation or in an existing exposure situation, the implementation of optimized protection strategies should result in levels of dose, risk or activity concentration below the reference level and as low as reasonably achievable, as long as these protection strategies are justified, with account taken of national factors The requirements of GSR Part 3 [2] for optimization of protection and safety, including the use of dose constraints and reference levels, for each of the three exposure situations, are presented in Section 3 of this Safety Guide. A table summarizing the values for the dose constraints and for reference levels as applicable for each exposure situation as required in GSR Part 3 [2] is presented in the Appendix. Dose limits Paragraph 2.11 of GSR Part 3 [2] states that: For planned exposure situations other than for medical exposure, each party with responsibilities for protection and safety shall ensure that, when relevant requirements apply to that party, specified dose limits are not exceeded Dose limits apply for exposure of workers and for public exposure in planned exposure situations only. Dose limits for members of the public are presented in Section 3. Dose limits do not apply for medical exposures. The annual effective dose to members of the public, for comparison with the dose limit for effective dose, is the sum of the effective dose from external exposure in one year and the committed effective dose from intakes within the same year Doses to members of the public are usually not assessed by individual monitoring, as for occupational exposure, but are generally estimated using 10

29 the predictions of models that simulate the transport of radionuclides in the environment combined with data on habits of members of the public for relevant exposure scenarios and dose coefficients. RESPONSIBILITIES Responsibilities of the government The responsibilities of the government with regard to protection and safety for all three exposure situations are established in general terms in paras of GSR Part 3 [2]. These include: (a) (b) (c) (d) (e) Establishing an effective legal and regulatory framework for protection and safety in all exposure situations; Establishing legislation that meets specified requirements; Establishing an independent regulatory body with the necessary legal authority, competence and resources; Establishing requirements for education and training in protection and safety; Ensuring arrangements are in place for the provision of technical services and education and training services The responsibilities of the government or the regulatory body with regard to protection of the public in planned exposure situations are set out in Requirement 29 and in paras and of GSR Part 3 [2]. These responsibilities include: (a) (b) (c) Establishing the responsibilities of registrants, licensees and suppliers and of providers of consumer products in relation to the application of requirements for public exposure in planned exposure situations; Establishing and enforcing requirements for the optimization of protection and safety, including establishing or approving constraints on dose and constraints on risk to be used in the optimization of protection and safety for members of the public; Establishing dose limits for public exposure in planned exposure situations The responsibilities of the government for protection of the public in emergency exposure situations are set out in Requirements 43 and 44 of 11

30 GSR Part 3 [2] in general terms, and in greater detail in GSR Part 7 [4]. Some of the responsibilities of the government include: (a) (b) (c) Establishing an integrated and coordinated emergency management system; Developing justified and optimized protection strategies at the preparedness stage; Ensuring safe and effective implementation of emergency arrangements in accordance with the protection strategy. In addition to assigning responsibilities to the government in general terms, GSR Part 3 [2] and GSR Part 7 [4] assign specific responsibilities in emergency preparedness and response to response organizations The responsibilities of the government for protection of the public in existing exposure situations are set out in Requirements 47, 48, 49 and 50 of GSR Part 3 [2]. The government is required to ensure that existing exposure situations that have been identified are evaluated to determine which public exposures are of concern from the point of view of radiation protection, and to ensure that remedial actions and protective actions are justified and that protection and safety is optimized. The government is required to ensure that provision for the management of existing exposure situations is included in the legal and regulatory framework for protection and safety. The government, in the legal and regulatory framework, is required to assign responsibilities for the establishment and implementation of protection strategies to the regulatory body and to other relevant authorities, and, as appropriate, to registrants, licensees and other parties involved in the implementation of remedial actions and protective actions. Responsibilities of the regulatory body The responsibilities of the regulatory body with regard to protection and safety that are applicable to all three exposure situations are set out in Requirements of GSR Part 1 (Rev. 1) [3] and in Requirement 3 and paras of GSR Part 3 [2]. These responsibilities include: (a) (b) (c) Establishing requirements for applying the principles of radiation protection; Establishing a regulatory system that meets specified requirements; Ensuring the application of the requirements for education and training in protection and safety; 12