IAEA-TECDOC-1568 Intercomparison Exercise on Internal Dose Assessment Final report of a joint IAEA–IDEAS project September 2007 IAEA SAFETY 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, and also general safety (i.e. all these areas of safety). The publication categories in the series are Safety Fundamentals, Safety Requirements and Safety Guides. Safety standards are coded according to their coverage: nuclear safety (NS), radiation safety (RS), transport safety (TS), waste safety (WS) and general safety (GS). 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OTHER SAFETY 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 and protection in nuclear activities are issued in other publications series, in particular the Safety Reports Series. Safety Reports provide practical examples and detailed methods that can be used in support of the safety standards. Other IAEA series of safety related publications are the Provision for the Application of Safety Standards Series, the Radiological Assessment Reports Series and the International Nuclear Safety Group’s INSAG Series. The IAEA also issues reports on radiological accidents and other special publications. Safety related publications are also issued in the Technical Reports Series, the IAEA-TECDOC Series, the Training Course Series and the IAEA Services Series, and as Practical Radiation Safety Manuals and Practical Radiation Technical Manuals. Security related publications are issued in the IAEA Nuclear Security Series. IAEA-TECDOC-1568 Intercomparison Exercise on Internal Dose Assessment Final report of a joint IAEA–IDEAS project September 2007 The originating Section of this publication in the IAEA was: Section International Atomic Energy Agency Wagramer Strasse 5 P.O. Box 100 A-1400 Vienna, Austria INTERCOMPARISON EXERCISE ON INTERNAL DOSE ASSESSMENT IAEA, VIENNA, 2007 IAEA-TECDOC-1568 ISBN 978–92–0–106307–6 ISSN 1011–4289 © IAEA, 2007 Printed by the IAEA in Austria September 2007 FOREWORD There have been several intercomparison exercises organized already at national and international levels for the assessment of occupational exposure due to intakes of radionuclides. These intercomparison exercises revealed significant differences in approaches, methods and assumptions, and consequently in the results. Because of the relevance of the issue for internal dosimetrists, the IAEA organized a new intercomparison exercise in cooperation with the IDEAS project General Guidelines for the Evaluation of Incorporation Monitoring Data, launched under the 5th EU Framework Programme (EU Contract No. FIKR-CT2001-00160). This new intercomparison exercise focused especially on the effect of the guidelines for harmonization of internal dosimetry. It also considered the following aspects: — to provide possibilities for the participating laboratories to check the quality of their internal dose assessment methods in applying the recent ICRP recommendations (e.g. for the new respiratory tract model); — to compare different approaches in interpretation of internal contamination monitoring data; — to quantify the differences in internal dose assessments based on the new guidelines or on other procedures, respectively; — to provide some figures for the influence of the input parameters on the monitoring results; and — to provide a broad forum for information exchange. Several cases have been selected for this exercise with the aim of covering a wide range of practices in the nuclear fuel cycle and in medical applications. The cases were: 1. Acute intake of HTO; 2. Acute inhalation of fission products 137Cs and 90Sr; 3. Intake of 60Co; 4. Repeated intakes of 131I; 5. Intake of enriched uranium; 6. Single intake of plutonium radionuclides and 241Am. An Internet based approach had been used for the presentation of the cases, collection of responses and potential discussion of the results. Solutions to these cases were reported by 80 participants worldwide. This report presents and discusses the main findings and recommendations for future actions. The IAEA officer responsible for the compilation of this publication was J. Zeger of the Division of Radiation, Transport and Waste Safety. EDITORIAL NOTE The use of particular designations of countries or territories does not imply any judgement by the publisher, the IAEA, as to the legal status of such countries or territories, of their authorities and institutions or of the delimitation of their boundaries. The mention of names of specific companies or products (whether or not indicated as registered) does not imply any intention to infringe proprietary rights, nor should it be construed as an endorsement or recommendation on the part of the IAEA. CONTENTS PART I. INTRODUCTION 1. BACKGROUND.................................................................................................................... 1 2. STATE OF THE ART............................................................................................................ 1 3. GENERAL REQUIREMENTS ............................................................................................. 2 PART II. THE IDEAS PROJECT 4. ORGANIZATION .................................................................................................................7 5. DEVELOPMENT OF THE GENERAL GUIDELINES....................................................... 8 6. THE IDEAS GUIDELINES FOR EVALUATION OF MONITORING DATA.................. 8 6.1. Introduction.................................................................................................................... 8 6.2. Harmonization ............................................................................................................... 9 6.3. Accuracy........................................................................................................................ 9 6.4. Proportionality ............................................................................................................... 9 6.5. Level of task .................................................................................................................. 9 PART III. PRACTICAL TESTING OF THE GENERAL GUIDELINES 7. BACKGROUND.................................................................................................................. 13 7.1. Objectives .................................................................................................................... 13 7.2. Scope of the intercomparison ...................................................................................... 13 7.3. Schedule....................................................................................................................... 14 7.4. Participation................................................................................................................. 15 7.5. Procedure for selecting data for statistical evaluation ................................................. 16 PART IV. ASSESSMENT OF THE CASES 8. CASE 1: ACUTE INHALATION OF HTO........................................................................ 21 8.1. Case description........................................................................................................... 21 8.1.1. The event...................................................................................................... 21 8.1.2. Additional information.................................................................................21 8.1.3. Body monitoring data .................................................................................. 21 8.1.4. Excretion monitoring data............................................................................ 22 8.1.5. Personal data................................................................................................ 23 8.1.6. Other comments relevant for intake and dose estimation............................ 23 8.2. Assessment of case ...................................................................................................... 24 8.2.1. Simple hand calculation..............................................................................