IAEA Safety Standards
for protecting people and the environment
General Safety Guide No. GSG-7
Occupational
Radiation Protection
Jointly sponsored by
IAEA Safety Standards Series No. GSG-7
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
http://www-ns.iaea.org/standards/
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 email 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.
OCCUPATIONAL
RADIATION PROTECTION
AFGHANISTAN ALBANIA ALGERIA ANGOLA
ANTIGUA AND BARBUDA ARGENTINA
ARMENIA AUSTRALIA AUSTRIA AZERBAIJAN BAHAMAS BAHRAIN BANGLADESH BARBADOS BELARUS BELGIUM BELIZE BENIN
BOLIVIA, PLURINATIONAL STATE OF
BOSNIA AND HERZEGOVINA BOTSWANA
BRAZIL
BRUNEI DARUSSALAM BULGARIA
BURKINA FASO BURUNDI CAMBODIA CAMEROON CANADA
CENTRAL AFRICAN REPUBLIC CHADCHILE CHINA COLOMBIA CONGO COSTA RICA CÔTE D’IVOIRE CROATIA CUBACYPRUS CZECH REPUBLIC DEMOCRATIC REPUBLIC
OF THE CONGO DENMARK DJIBOUTI DOMINICA
DOMINICAN REPUBLIC ECUADOR
EGYPT EL SALVADOR ERITREA ESTONIA ESWATINI ETHIOPIA FIJIFINLAND FRANCE GABON GEORGIA
GERMANY GHANA GREECE GRENADA GUATEMALA GUYANA HAITI HOLY SEE HONDURAS HUNGARY ICELAND INDIA INDONESIA
IRAN, ISLAMIC REPUBLIC OF IRAQIRELAND
ISRAEL ITALY JAMAICA JAPAN JORDAN KAZAKHSTAN KENYA
KOREA, REPUBLIC OF KUWAIT
KYRGYZSTAN
LAO PEOPLE’S DEMOCRATIC REPUBLIC
LATVIA LEBANON LESOTHO LIBERIA LIBYA
LIECHTENSTEIN LITHUANIA LUXEMBOURG MADAGASCAR MALAWI MALAYSIA MALIMALTA
MARSHALL ISLANDS MAURITANIA MAURITIUS MEXICO MONACO MONGOLIA MONTENEGRO MOROCCO MOZAMBIQUE MYANMAR NAMIBIA NEPAL NETHERLANDS NEW ZEALAND NICARAGUA NIGER NIGERIA NORWAY OMANPAKISTAN
PALAU PANAMA
PAPUA NEW GUINEA PARAGUAY PERUPHILIPPINES POLAND PORTUGAL QATAR
REPUBLIC OF MOLDOVA ROMANIA
RUSSIAN FEDERATION RWANDA
SAINT VINCENT AND THE GRENADINES SAN MARINO SAUDI ARABIA SENEGAL SERBIA SEYCHELLES SIERRA LEONE SINGAPORE SLOVAKIA SLOVENIA SOUTH AFRICA SPAIN SRI LANKA SUDAN SWEDEN SWITZERLAND
SYRIAN ARAB REPUBLIC TAJIKISTAN
THAILAND
THE FORMER YUGOSLAV REPUBLIC OF MACEDONIA TOGOTRINIDAD AND TOBAGO TUNISIA
TURKEY TURKMENISTAN UGANDA UKRAINE
UNITED ARAB EMIRATES UNITED KINGDOM OF
GREAT BRITAIN AND NORTHERN IRELAND UNITED REPUBLIC
OF TANZANIA
UNITED STATES OF AMERICA URUGUAY
UZBEKISTAN VANUATU
VENEZUELA, BOLIVARIAN REPUBLIC OF
VIET NAM YEMEN ZAMBIA ZIMBABWE The following States are Members of the International Atomic Energy Agency:
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 1957.
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’’.
AFGHANISTAN ALBANIA ALGERIA ANGOLA
ANTIGUA AND BARBUDA ARGENTINA
ARMENIA AUSTRALIA AUSTRIA AZERBAIJAN BAHAMAS BAHRAIN BANGLADESH BARBADOS BELARUS BELGIUM BELIZE BENIN
BOLIVIA, PLURINATIONAL STATE OF
BOSNIA AND HERZEGOVINA BOTSWANA
BRAZIL
BRUNEI DARUSSALAM BULGARIA
BURKINA FASO BURUNDI CAMBODIA CAMEROON CANADA
CENTRAL AFRICAN REPUBLIC CHADCHILE CHINA COLOMBIA CONGO COSTA RICA CÔTE D’IVOIRE CROATIA CUBACYPRUS CZECH REPUBLIC DEMOCRATIC REPUBLIC
OF THE CONGO DENMARK DJIBOUTI DOMINICA
DOMINICAN REPUBLIC ECUADOR
EGYPT EL SALVADOR ERITREA ESTONIA ESWATINI ETHIOPIA FIJIFINLAND FRANCE GABON GEORGIA
GERMANY GHANA GREECE GRENADA GUATEMALA GUYANA HAITI HOLY SEE HONDURAS HUNGARY ICELAND INDIA INDONESIA
IRAN, ISLAMIC REPUBLIC OF IRAQIRELAND
ISRAEL ITALY JAMAICA JAPAN JORDAN KAZAKHSTAN KENYA
KOREA, REPUBLIC OF KUWAIT
KYRGYZSTAN
LAO PEOPLE’S DEMOCRATIC REPUBLIC
LATVIA LEBANON LESOTHO LIBERIA LIBYA
LIECHTENSTEIN LITHUANIA LUXEMBOURG MADAGASCAR MALAWI MALAYSIA MALIMALTA
MARSHALL ISLANDS MAURITANIA MAURITIUS MEXICO MONACO MONGOLIA MONTENEGRO MOROCCO MOZAMBIQUE MYANMAR NAMIBIA NEPAL NETHERLANDS NEW ZEALAND NICARAGUA NIGER NIGERIA NORWAY OMANPAKISTAN
PALAU PANAMA
PAPUA NEW GUINEA PARAGUAY PERUPHILIPPINES POLAND PORTUGAL QATAR
REPUBLIC OF MOLDOVA ROMANIA
RUSSIAN FEDERATION RWANDA
SAINT VINCENT AND THE GRENADINES SAN MARINO SAUDI ARABIA SENEGAL SERBIA SEYCHELLES SIERRA LEONE SINGAPORE SLOVAKIA SLOVENIA SOUTH AFRICA SPAIN SRI LANKA SUDAN SWEDEN SWITZERLAND
SYRIAN ARAB REPUBLIC TAJIKISTAN
THAILAND
THE FORMER YUGOSLAV REPUBLIC OF MACEDONIA TOGOTRINIDAD AND TOBAGO TUNISIA
TURKEY TURKMENISTAN UGANDA UKRAINE
UNITED ARAB EMIRATES UNITED KINGDOM OF
GREAT BRITAIN AND NORTHERN IRELAND UNITED REPUBLIC
OF TANZANIA
UNITED STATES OF AMERICA URUGUAY
UZBEKISTAN VANUATU
VENEZUELA, BOLIVARIAN REPUBLIC OF
VIET NAM YEMEN ZAMBIA ZIMBABWE The following States are Members of the International Atomic Energy Agency:
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 1957.
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’’.
IAEA SAFETY STANDARDS SERIES No. GSG-7
OCCUPATIONAL
RADIATION PROTECTION
GENERAL SAFETY GUIDE
JOINTLY SPONSORED BY THE
INTERNATIONAL ATOMIC ENERGY AGENCY AND INTERNATIONAL LABOUR OFFICE
INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA, 2018
COPYRIGHT NOTICE
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© IAEA, 2018 Printed by the IAEA in Austria
October 2018 STI/PUB/1785
IAEA Library Cataloguing in Publication Data Names: International Atomic Energy Agency.
Title: Occupational radiation protection / International Atomic Energy Agency.
Description: Vienna : International Atomic Energy Agency, 2018. | Series: IAEA safety standards series, ISSN 1020–525X ; no. GSG-7 | Includes bibliographical references.
Identifiers: IAEAL 18-01183 | ISBN 978–92–0–102917–1 (paperback : alk. paper) Subjects: LCSH: Radiation — Safety measures. | Radiation dosimetry. | Industrial
safety.
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 1958. 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
PREFACE
Occupational exposure to ionizing radiation can occur in a range of industries, medical institutions, educational and research establishments, and nuclear fuel cycle facilities. Appropriate levels of radiation protection of workers are essential for the safe and justified use of radiation, radioactive material and nuclear energy.
In 2006, the IAEA published the Fundamental Safety Principles, IAEA Safety Standards Series No. SF-1, jointly sponsored by the European Atomic Energy Community (Euratom), the Food and Agriculture Organization of the United Nations (FAO), the IAEA, the International Labour Organization (ILO), the International Maritime Organization, the OECD Nuclear Energy Agency (OECD/NEA), the Pan American Health Organization (PAHO), the United Nations Environment Programme (UNEP) and the World Health Organization (WHO). That publication sets out the safety objective and the principles of protection and safety.
In 2014, the IAEA published Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards, IAEA Safety Standards Series No. GSR Part 3, jointly sponsored by the European Commission, FAO, IAEA, ILO, OECD/NEA, PAHO, UNEP and WHO. This publication establishes the requirements that are designed to meet the fundamental safety objective and to apply the safety principles specified in the Fundamental Safety Principles.
The establishment of safety requirements and guidance on occupational radiation protection is a major element of the support for radiation protection and safety provided by the IAEA to its Member States. The objective of the IAEA’s activities on occupational radiation protection is to promote an internationally harmonized approach to occupational radiation protection through the development and application of standards for optimizing protection and safety, restricting exposures and applying current radiation protection techniques in the workplace.
This Safety Guide was prepared jointly by the IAEA and the International Labour Office to provide guidance on fulfilling the requirements of GSR Part 3 with respect to occupational exposure. It provides general guidance on the exposure conditions for which radiation protection programmes are required to be established, including the setting up of monitoring programmes to assess radiation doses to workers arising from exposure due to external sources of radiation and from exposure due to intakes of radionuclides. It also provides specific guidance on the assessment of doses from exposure due to external sources of radiation and from exposure due to intakes of radionuclides.
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.
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 measures1 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.
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.
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
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 General Safety Requirements Specific Safety Requirements
Safety Fundamentals Fundamental Safety Principles
Collection of Safety Guides
FIG. 1. The long term structure of the IAEA Safety Standards Series.
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
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
Secretariat and consultants:
drafting of new or revision of existing safety standard
Draft
Endorsement by the CSS Final draft
Review by safety standards
committee(s) Member States
Comments Draft Outline and work plan prepared by the Secretariat;
review by the safety standards committees and the CSS
FIG. 2. The process for developing a new safety standard or revising an existing standard.
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 http://www-ns.iaea.org/standards/safety-glossary.htm). 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.
CONTENTS
1. INTRODUCTION . . . 1
Background (1.1–1.7). . . 1
Objective (1.8) . . . 2
Scope (1.9) . . . 3
Structure (1.10–1.12) . . . 3
2. FRAMEWORK FOR OCCUPATIONAL RADIATION PROTECTION. . . 4
Occupational exposure and types of exposure situation (2.1–2.4). . . . 4
Principles of radiation protection (2.5–2.14) . . . 6
Responsibilities (2.15–2.19). . . 8
Graded approach (2.20–2.22) . . . 10
Management system (2.23–2.26) . . . 11
Dosimetric quantities (2.27–2.72) . . . 12
3. EXPOSURE OF WORKERS IN PLANNED EXPOSURE SITUATIONS (3.1–3.7) . . . 24
Optimization (3.8–3.33) . . . 26
Dose limitation (3.34–3.48) . . . 33
Radiation protection programme (3.49–3.158) . . . 37
Exposure of workers due to natural sources (3.159–3.181) . . . 68
4. EXPOSURE OF WORKERS IN A NUCLEAR OR RADIOLOGICAL EMERGENCY (4.1–4.4). . . 77
Emergency planning and responsibilities (4.5–4.6) . . . 78
Protection of emergency workers (4.7–4.17) . . . 79
Managing the exposure of emergency workers (4.18–4.25) . . . 83
Assessment of exposure (4.26–4.29) . . . 85
Medical attention (4.30–4.32) . . . 86
5. EXPOSURE OF WORKERS IN EXISTING EXPOSURE SITUATIONS (5.1–5.7) . . . 87
Protection strategies (5.8–5.13) . . . 88
Justification (5.14–5.15). . . 90
Optimization (5.16–5.23) . . . 90
Exposure arising from remedial actions in areas with contamination by residual radioactive material (5.24–5.44). . . 92
Exposure due to radon (5.45–5.72) . . . 97
Exposure to cosmic radiation (5.73–5.88) . . . 105
6. PROTECTION OF WORKERS IN SPECIAL CASES (6.1) . . . 109
Female workers during and after pregnancy (6.2–6.20). . . 110
Itinerant workers (6.21–6.100) . . . 114
7. MONITORING AND ASSESSMENT OF OCCUPATIONAL EXPOSURE . . . 138
Assessment of external exposure (7.1–7.132) . . . 138
Assessment of internal exposure (7.133–7.227). . . 172
Assessment of exposure in emergencies (7.228–7.243). . . 195
Skin contamination (7.244–7.250) . . . 199
Records of occupational exposure (7.251–7.273) . . . 201
8. MANAGEMENT SYSTEM FOR PROVIDERS OF TECHNICAL SERVICES. . . 207
General considerations (8.1–8.14) . . . 207
Management responsibility (8.15–8.25). . . 211
Conduct of processes (8.26–8.48) . . . 214
Measurement, assessment and improvement of performance (8.49–8.70). . . 218
Additional guidance for providers of calibration and testing services (8.71–8.101) . . . 223
9. ENGINEERED CONTROLS, ADMINISTRATIVE CONTROLS AND PERSONAL PROTECTIVE EQUIPMENT. . . 230
General considerations (9.1–9.7) . . . 230
Shielding (9.8–9.9) . . . 231
Ventilation (9.10–9.19). . . 232
Dust control (9.20–9.21). . . 235
Spillage of radioactive material (9.22–9.23) . . . 235
Surface contamination (9.24–9.46) . . . 236
Decontamination of equipment and
decontamination of personnel (9.47–9.52) . . . 243
Personal protective equipment (9.53–9.64) . . . 244
Job rotation (9.65). . . 247
Special considerations for mineral processing operations involving naturally occurring radioactive material (9.66–9.72) . . . 247
10. WORKERS’ HEALTH SURVEILLANCE . . . 248
Responsibilities (10.1–10.7). . . 248
Programme for workers’ health surveillance (10.8–10.10) . . . 251
Medical examination of workers (10.11–10.24). . . 251
Notification of ailments and of overexposure (10.25–10.27). . . 255
Medical records (10.28) . . . 255
Management for overexposed workers (10.29–10.34). . . 255
APPENDIX I: EXPOSURE OF WORKERS TO NATURALLY OCCURRING RADIOACTIVE MATERIAL . . . 257
APPENDIX II: METHODS AND SYSTEMS FOR INDIVIDUAL MONITORING FOR ASSESSMENT OF EXTERNAL EXPOSURE . . . 259
APPENDIX III: WORKPLACE MONITORING INSTRUMENTS FOR ASSESSMENT OF EXTERNAL EXPOSURE . . . 271
APPENDIX IV: BIOKINETIC MODELS FOR ASSESSMENT OF INTERNAL EXPOSURE. . . 280
APPENDIX V: METHODS FOR INDIVIDUAL MONITORING OF INTERNAL CONTAMINATION . . . 286
REFERENCES . . . 305
ANNEX: TECHNIQUES FOR RETROSPECTIVE DOSIMETRY . . . 323
ABBREVIATIONS . . . 333
CONTRIBUTORS TO DRAFTING AND REVIEW . . . 335
1. INTRODUCTION
BACKGROUND
1.1. Occupational exposure to radiation can occur as a result of various human activities, including: work associated with the different stages of the nuclear fuel cycle; the use of radiation in medicine, scientific research, agriculture and industry; and occupations that involve exposure due to natural sources.
1.2. IAEA Safety Standards Series No. SF-1, Fundamental Safety Principles [1], presents the fundamental safety objective and principles of protection and safety.
Requirements designed to meet the fundamental safety objective and to apply the safety principles specified in SF-1 [1], including requirements for the protection of workers exposed to sources of radiation, are established in IAEA Safety Standards Series No. GSR Part 3, Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards [2], jointly sponsored by the IAEA and seven other international organizations.
1.3. This Safety Guide, prepared jointly by the IAEA and the International Labour Office, provides guidance on fulfilling the requirements of GSR Part 3 [2]
with respect to occupational exposure. It provides general guidance on the exposure conditions for which radiation protection programmes are required to be established, including the setting up of monitoring programmes to assess radiation doses to workers arising from exposure due to external sources of radiation and from exposure due to intakes of radionuclides. It also provides specific guidance on the assessment of doses from exposure due to external sources of radiation and from exposure due to intakes of radionuclides.
1.4. Recommendations for a system of radiation protection were developed by the International Commission on Radiological Protection (ICRP) [3]. These and other current recommendations of the ICRP and the International Commission on Radiation Units and Measurements (ICRU) have been taken into account in preparing this Safety Guide.
1.5. It is recognized that radiation protection is only one component to be addressed to protect the overall health and safety of the worker. The radiation protection programme has to be established and managed together with other health and safety disciplines, such as industrial hygiene, medical hygiene, industrial safety and fire safety.
1.6. Guidance on meeting the requirements of GSR Part 3 [2] for occupational radiation protection is provided in this Safety Guide. It gives general guidance on the development of occupational radiation protection programmes, in accordance with the requirements of GSR Part 3 [2] and appropriate for the sources of radiation likely to be encountered in the workplaces in question. It also gives more detailed guidance on the monitoring and assessment of workers’ exposure due to external radiation sources and from intakes of radionuclides. This Safety Guide reflects the current internationally accepted principles and recommended practices in occupational radiation protection, with account taken of the major changes that have occurred since 1999.
1.7. This Safety Guide updates the guidance given in five previous Safety Guides, which are hereby superseded: Occupational Radiation Protection1; Assessment of Occupational Exposure Due to Intakes of Radionuclides2; Assessment of Occupational Exposure Due to External Sources of Radiation3; Occupational Radiation Protection in the Mining and Processing of Raw Materials4; and The Management System for Technical Services in Radiation Safety5.
OBJECTIVE
1.8. The objective of this Safety Guide is to provide guidance on the control of occupational exposure. The recommendations given are intended for regulatory bodies, but this Safety Guide will also be useful to: employers, licensees and registrants; management bodies and their specialist advisers; and health and safety committees concerned with the radiation protection of workers. The
1 INTERNATIONAL ATOMIC ENERGY AGENCY, INTERNATIONAL LABOUR OFFICE, Occupational Radiation Protection, IAEA Safety Standards Series No. RS-G-1.1, IAEA, Vienna (1999).
2 INTERNATIONAL ATOMIC ENERGY AGENCY, INTERNATIONAL LABOUR OFFICE, Assessment of Occupational Exposure Due to Intakes of Radionuclides, IAEA Safety Standards Series No. RS-G-1.2, IAEA, Vienna (1999).
3 INTERNATIONAL ATOMIC ENERGY AGENCY, INTERNATIONAL LABOUR OFFICE, Assessment of Occupational Exposure Due to External Sources of Radiation, IAEA Safety Standards Series No. RS-G-1.3, IAEA, Vienna (1999).
4 INTERNATIONAL LABOUR OFFICE, Occupational Radiation Protection in the Mining and Processing of Raw Materials, IAEA Safety Standards Series No. RS-G-1.6, IAEA, Vienna (2004).
5 INTERNATIONAL ATOMIC ENERGY AGENCY, The Management System for Technical Services in Radiation Safety, IAEA Safety Standards Series No. GS-G-3.2, IAEA, Vienna (2008).
recommendations may also be used by workers and their representatives to encourage safe working practices.
SCOPE
1.9. This Safety Guide addresses the technical and organizational aspects of the control of occupational exposure. The intention is to provide an integrated approach to the control of exposure, and the control of potential exposure, due to external exposure and internal exposure to radiation from both artificial sources and natural sources.
STRUCTURE
1.10. Section 2 gives an overview of the basic framework for occupational radiation protection, including an explanation of the three types of exposure situation (planned exposure situations, emergency exposure situations and existing exposure situations), the basic principles of radiation protection and their application to the protection of workers, and the dosimetric quantities used.
Sections 3–5 provide guidance on meeting the requirements of GSR Part 3 [2] in each of the three types of exposure situation. Section 3 addresses occupational radiation protection in planned exposure situations, including application of the principles of optimization and of dose limitation, the radiation protection programme, and specific guidance on the protection of workers exposed due to natural sources. Section 4 addresses the protection of workers in a nuclear or radiological emergency, including the preparation of an emergency plan, the application of the principles of optimization and dose limitation in emergencies, and the assessment and management of exposures of emergency workers.
Section 5 addresses the protection of workers in existing exposure situations, including the establishment of an appropriate protection strategy and legal and regulatory framework. It also provides specific guidance on the protection of workers against exposure due to residual radioactive material from past activities or accidents, radon in workplaces and cosmic radiation in aircraft and spacecraft.
1.11. Sections 6–10 provide guidance on more specific aspects of occupational radiation protection. Section 6 describes the special measures to be taken for the protection of two particular groups of workers: female workers during and after pregnancy and itinerant workers. Section 7 gives detailed guidance on the monitoring and assessment of occupational exposure, including: monitoring programmes, systems and equipment; the estimation of uncertainties; testing and
calibration; the interpretation of the results of monitoring; and the maintenance of records. The guidance covers both individual monitoring and workplace monitoring, addresses external exposure and internal exposure as well as skin contamination, and includes assessment of exposure in emergencies. Section 8 gives guidance on the management system for providers of technical services in occupational radiation protection, in particular calibration, testing and dosimetry services. Section 9 describes engineered and administrative controls for occupational protection and safety, including the maintenance of good air quality, the provision of adequate shielding and the control of contamination. Guidance on the use of personal protective equipment is also provided. Section 10 addresses programmes for workers’ health surveillance, including guidance on the medical examination of workers and medical records, as well as on the care of overexposed workers.
1.12. Five appendices and an annex provide additional, more detailed guidance relating to the exposure of workers due to naturally occurring radioactive material, methods and systems for individual monitoring for assessment of external exposure, workplace monitoring instruments for assessment of external exposure, methods for monitoring and assessment of internal exposure (including biokinetic modelling), and techniques for retrospective dosimetry.
2. FRAMEWORK FOR OCCUPATIONAL RADIATION PROTECTION
OCCUPATIONAL EXPOSURE AND TYPES OF EXPOSURE SITUATION 2.1. Occupational exposure is the exposure of workers incurred during the course of their work, regardless of the exposure situation. For the purpose of establishing practical requirements for protection and safety, GSR Part 3 [2]
distinguishes between three different types of exposure situation: planned exposure situations, emergency exposure situations and existing exposure situations. As stated in para. 1.20 of GSR Part 3 [2]:
“(a) 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 of controlling exposure in planned exposure situations is by good design of facilities, equipment and operating procedures, and by training….
(b) 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 to reduce adverse consequences. 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.
(c) An existing exposure situation is a situation of exposure that already exists when a decision on the need for control needs to be taken.
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 not subject to regulatory control or that remains after an emergency exposure situation.”
This Safety Guide gives guidance on the protection of workers in each of these three types of exposure situation.
2.2. As stated in para. 1.21 of GSR Part 3 [2]:
“The descriptions that are given in para. 1.20 of the three types of exposure situation are not always sufficient to determine unequivocally which type of exposure situation applies for particular circumstances. For instance, the transitions from an emergency exposure situation to an existing exposure situation may occur progressively over time; and some exposures due to natural sources may have some characteristics of both planned exposure situations and existing exposure situations. In these Standards, the most appropriate type of exposure situation for particular circumstances has been determined by taking practical considerations into account.”
2.3. Reference is made to potential exposure in para. 1.20(a) of GSR Part 3 [2]
as follows:
“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 accident or from an event or a sequence of events that may occur but is not certain to occur, this is referred to as ‘potential exposure’.
…….
“If an event or a sequence of events that has been considered in the assessment of potential exposure does actually occur, it may be treated either as a planned exposure situation or, if an emergency has been declared, as an emergency exposure situation.”
2.4. Some exposures are excluded from the scope of GSR Part 3 [2].
Paragraph 1.42 of GSR Part 3 [2] states that:
“These Standards apply to all situations involving radiation exposure that is amenable to control. Exposures deemed to be not amenable to control are excluded from the scope of these Standards.8
“8 It is generally accepted, for example, that it is not feasible to control 40K in the body or cosmic radiation at the surface of the Earth.”
Guidance is given in Section 3 on the components of exposure due to natural sources of radiation that may be required to be subject to control as occupational exposure.
PRINCIPLES OF RADIATION PROTECTION
2.5. The three general principles of radiation protection, which concern justification, optimization of protection and application of dose limits (limitation of doses), are expressed in Safety Principles 4–6 and 10 of the Fundamental Safety Principles [1]. In terms of Requirement 1 of GSR Part 3 [2], those “with responsibilities for protection and safety shall ensure that the principles of radiation protection are applied for all exposure situations.”
Justification
2.6. Paragraphs 2.8 and 2.9 of GSR Part 3 [2] state that:
“2.8. 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.
“2.9. 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.”
2.7. In planned exposure situations, this means that no practice or source within a practice should be authorized unless the practice produces sufficient benefit to the exposed individuals or to society to offset the harm (including radiation detriment) that it might cause; that is, unless the practice is justified, with societal, economic and other relevant factors having been taken into account.
2.8. The process of determining whether a practice is justified involves consideration of all radiation doses received by workers and members of the public. In general, the assumption made in this Safety Guide is that the process of justification has already taken place and that the contribution of occupational exposure to the total radiation detriment has been taken into account. The subject of justification for planned exposure situations is therefore not considered in detail in this Safety Guide. Guidance on justification is given in IAEA Safety Standards Series No. GSG-5, Justification of Practices, Including Non-medical Human Imaging [4].
Optimization
2.9. 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 optimized9.
“9 ‘Protection and safety is optimized’ means that optimization of protection and safety has been applied and the result of that process has been implemented.”
2.10. In planned exposure situations, in relation to exposures due to any particular source within a practice, protection and safety is required to be optimized in order that the magnitude of individual doses, the number of people exposed and the likelihood of incurring exposures all be kept as low as reasonably achievable, economic and societal factors being taken into account, with the restriction that the doses to individuals delivered by the source be subject to dose constraints.
This principle is of particular importance for the implementation of radiation protection measures in the workplace and therefore underlies much of the more detailed guidance given in Section 3.
Dose limitation
2.11. 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.”
2.12. Dose limits apply only in planned exposure situations. In such situations, the exposure of individuals should be restricted so that neither the total effective dose nor the total equivalent dose to relevant tissues or organs, caused by possible combinations of exposures due to authorized practices, exceeds any relevant dose limit.
2.13. The limit on effective dose represents the level above which the risk of stochastic effects due to radiation exposure is considered to be unacceptable. For localized exposure of the lens of the eye, the extremities and the skin, this limit on effective dose is not sufficient to ensure the avoidance of deterministic effects.
Limits on equivalent dose to these tissues and organs are, therefore, specified for such situations.
2.14. Guidance on the application of the dose limits for occupational exposure is given in Section 3.
RESPONSIBILITIES The government
2.15. The responsibilities of the government6 with regard to protection and safety are set out in paras 2.13–2.28 of GSR Part 3 [2]. These include:
(a) Establishing an effective legal and regulatory framework for protection and safety in all exposure situations;
(b) Establishing legislation that meets specified requirements;
(c) Establishing an independent regulatory body with the necessary legal authority, competence and resources;
6 Since States have different legal structures, the term ‘government’ here is to be understood in a broad sense and, accordingly, is interchangeable with the term ‘State’.
(d) Establishing requirements for education and training in protection and safety;
(e) Ensuring that arrangements are in place for the provision of technical services and education and training services.
The regulatory body
2.16. The responsibilities of the regulatory body with regard to protection and safety are set out in paras 2.29–2.38 of GSR Part 3 [2]. These include:
(a) Establishing requirements for applying the principles of radiation protection;
(b) Establishing a regulatory system that meets specified requirements;
(c) Ensuring the application of the requirements for education and training in protection and safety;
(d) Ensuring that mechanisms are in place for the dissemination of lessons learned from incidents and accidents;
(e) Setting acceptance and performance criteria for sources and equipment with implications for protection and safety;
(f) Making provision for the establishment and maintenance of records.
2.17. The responsibilities of the regulatory body specific to occupational exposure in planned exposure situations are set out in paras 3.69–3.73 of GSR Part 3 [2].
The regulatory body is responsible for establishing and enforcing requirements for ensuring that protection and safety is optimized, ensuring that applicable dose limits are complied with, and monitoring and recording occupational exposures.
Employers, registrants and licensees
2.18. Requirement 4 of GSR Part 3 [2] states that “The person or organization responsible for facilities and activities that give rise to radiation risks shall have the prime responsibility for protection and safety....” In planned exposure situations, employers, registrants and licensees (hereinafter referred to simply as the ‘management’) are responsible for ensuring that protection and safety is optimized, that applicable dose limits are complied with, and that appropriate radiation protection programmes are established and implemented. Guidance on the content of the radiation protection programme is given in Section 3.
Compliance by workers
2.19. Requirement 22 of GSR Part 3 [2] states that “Workers shall fulfil their obligations and carry out their duties for protection and safety.” This
requirement reflects the fact that workers can, by their own actions, contribute to protection and safety for themselves and for others at work. The requirements on workers in this regard are listed in para. 3.83 of GSR Part 3 [2] and relate to: following rules and procedures; using monitoring equipment and personal protective equipment; cooperating in programmes for workers’ health surveillance and programmes for dose assessment; and accepting instruction and training.
Workers are also required to provide relevant information to the management and to act in a responsible manner with regard to protection and safety.
GRADED APPROACH
2.20. Paragraph 2.31 of GSR Part 3 [2] provides the basis for the graded approach to the control of exposure:
“The regulatory body shall adopt a graded approach to the implementation of the system of protection and safety, such that the application of regulatory requirements is commensurate with the radiation risks associated with the exposure situation.”
It is required as a general responsibility of the government to ensure that the overall application of the principles of radiation protection is in line with the graded approach (see para. 2.18 of GSR Part 3 [2]).
2.21. Requirement 6 of GSR Part 3 [2] refers to the graded approach in the more specific context of planned exposure situations:
“The application of the requirements of these Standards in planned exposure situations shall be commensurate with the characteristics of the practice or the source within a practice, and with the likelihood and magnitude of exposures.”
2.22. An important feature of the graded approach in planned exposure situations is the provision for exemption and clearance. Requirement 8 of GSR Part 3 [2]
states that:
“The government or the regulatory body shall determine which practices or sources within practices are to be exempted from some or all of the requirements of these Standards. The regulatory body shall
approve which sources, including materials and objects, within notified practices or authorized practices may be cleared from regulatory control.”
MANAGEMENT SYSTEM
2.23. Requirement 5 of GSR Part 3 [2] states that “The principal parties shall ensure that protection and safety are effectively integrated into the overall management system of the organizations for which they are responsible.”
For occupational exposure in planned exposure situations, the principal party is the employer. For emergency exposure situations or existing exposure situations, the principal parties are those persons or organizations designated to deal with the situation.
2.24. In terms of paras 2.47–2.52 of GSR Part 3 [2], the “principal parties shall demonstrate commitment to protection and safety at the highest levels within the organizations” and “shall ensure that the management system…is designed and applied to enhance protection and safety” while maintaining coherence between measures for protection and safety and other measures, such as those addressing operational performance and security.
2.25. Specific actions should be taken to provide the necessary degree of confidence in the measures taken for achieving protection and safety and to ensure their regular assessment and review. A safety culture should be promoted and maintained at all levels within the organization. The management system should also address human factors by supporting good performance and good practices to prevent human and organizational failures, with attention being given to the design of equipment, the development of operating procedures, limits and conditions, as appropriate, training and the use of safety systems to mitigate consequences of human error.
2.26. More detailed requirements and guidance on the management system for facilities and activities are given IAEA Safety Standards Series Nos GSR Part 2, Leadership and Management for Safety [5], and GS-G-3.1, Application of the Management System for Facilities and Activities [6], and also in International Labour Organization guidelines [7]. Recommendations and guidance on the management system for providers of technical services in relation to protection and safety is given in Section 8.
DOSIMETRIC QUANTITIES
2.27. The dosimetric quantities recommended for radiation protection purposes (the protection quantities), and in which the dose limits are expressed in GSR Part 3 [2], are the equivalent dose HT in tissue or organ T and the effective dose E.
2.28. The basic physical quantities include the particle fluence Φ, the kerma K and the absorbed dose D.
2.29. The determination of equivalent dose HT in tissue or organ T involves the use of a radiation weighting factor wR as a multiplier of absorbed dose for radiation type R to reflect the relative biological effectiveness (RBE) of the radiation in inducing stochastic effects at low doses:
T R T, R
R
H =
å
w D× (1)where DT, R is the average absorbed dose in tissue or organ T for radiation type R.
2.30. The determination of effective dose E involves the use of a tissue weighting factor wT as a multiplier of the equivalent dose for tissue T to account for the different sensitivities of different tissues and organs to the induction of stochastic effects:
T T
T
E=
å
w H× (2)which, on substituting for HT from Eq. (1), gives:
T R T, R
T R
E=
å å
w × w D× (3)2.31. The recommended values of wR and wT are based on a review of published biological and epidemiological studies, and are given in the definitions of terms in GSR Part 3 [2].
2.32. The protection quantities E and HT relate to the sum of the effective doses or equivalent doses, respectively, received from exposure due to external sources within a given time period, and the committed effective doses or committed equivalent doses, respectively, from exposure due to intakes of radionuclides
occurring within the same time period. The total effective dose E received or committed during a given time period can be estimated from the operational quantities by using the following equation:
( ) ( ) ( )
p j,ing j,ing j,inh j,inh
j j
E H d@ +
å
e g ×I +å
e g ×I (4)where
Hp(d) is the personal dose equivalent in soft tissue at an appropriate depth d below a specified point on the body during a given time period;
e(g)j,ing is the committed effective dose per unit intake by ingestion for radionuclide j by the group of age g during the same time period;
e(g)j,inh is the committed effective dose per unit intake by inhalation for radionuclide j by the group of age g during the same time period;
Ij,ing is the intake via ingestion of radionuclide j during the same time period;
and Ij,inh is the intake via inhalation of radionuclide j during the same time period.
For occupational exposure, the appropriate values of e(g)j,ing and e(g)j,inh are those for workers.
2.33. The dose limits are such that deterministic effects will not occur. For situations that could lead to severe deterministic effects (e.g. emergency exposure situations), the RBE of different types of radiation in causing severe deterministic effects should be considered. The recommended dosimetric quantity is the RBE weighted absorbed dose DT in tissue or organ T. The determination of RBE weighted absorbed dose involves the use of tissue specific and radiation specific factors RBET, R as multipliers of absorbed dose in a tissue or organ to take account of the RBE in causing the development of severe deterministic health effects from a given absorbed dose that is delivered in a tissue or organ by a given type of radiation. Recommended values of RBET, R for the development of selected severe deterministic effects are based on a review of published biological studies and are given in the definitions of terms in GSR Part 3 [2]. The use of effective dose is inappropriate for the assessment of tissue reactions. In such situations, it is necessary to estimate absorbed dose and to take into account the appropriate RBE as the basis for any assessment of radiation effects.
Operational quantities for individual monitoring in external dosimetry 2.34. Since radiation protection quantities cannot be measured directly, the ICRU introduced operational quantities for practical use in radiation protection where
