United Nations European Commission International Atomic Economic Commission Energy Agency for Europe Report on the Improvement of the Management of Radiation Protection Aspects in the Recycling of Metal Scrap UNITED NATIONS New York and Geneva, 2002 ECE/TRADE/278 UNITED NATIONS PUBLICATION Sales No. E.01.II.E.22 ISBN 92-1-116789-2 Copyright© United Nations, 2001. All rights reserved Printed at United Nations, Geneva (Switzerland) Experts who have actively participated in the drafting of this document: Ross BARTLEY – Bureau of International Recycling (BIR) Vittorio CIANI – European Commission Eduardo MORERE MOLINERO – European Commission Bernard DECKERS – Belgium Dominique DELATTRE – International Atomic Energy Agency (IAEA) Brian DODD – International Atomic Energy Agency (IAEA) David HARVEY – United Kingdom Nils HOLMBERG – Sweden Atsushi ISHIKAWA - Japan Michael ISAKOV – Russian Federation Michael MATTIA – United States of America Kiyotaka TERASHIMA - Japan Gerard VAN DER REIJDEN – Netherlands The work has been coordinated by Bernard DECKERS – Belgium and Bernard ROUX-FOUILLET – United Nations Economic Commission for Europe (UN/ECE) CONTENTS PREFACE ..................................................................................................................................................... 9 EXECUTIVE SUMMARY ............................................................................................................................11 1. General Presentation of the Issue..................................................................................................11 2. Recommendations for Improvement of the System.......................................................................12 A. Introduction of discrete radioactive sources ..............................................................................12 B. Introduction of uncontrolled radioactively contaminated material ...........................................13 C. Introduction of material with a very low level of radioactivity, released in accordance with a national regulatory framework..................................................................................................15 D. Controls on the output materials from the metal works – metal, slag and off-gas dust .............15 CHAPTER I. INTRODUCTION ..............................................................................................................17 CHAPTER II. OVERVIEW OF THE PRESENT SITUATION ..............................................................21 2.1. The Metal Recycling Loop..............................................................................................................21 2.2. Types of Metal Scrap ......................................................................................................................21 2.2.1. Home scrap (own arising or revert scrap).................................................................................21 2.2.2. New scrap (traded scrap) ..........................................................................................................21 2.2.3. Old scrap...................................................................................................................................22 2.3. Basic Information on Radioactivity ................................................................................................22 2.3.1. Radioactivity and radiation....................................................................................................22 2.3.2. Background radiation................................................................................................................22 2.3.3. Origin of the radioactivity.........................................................................................................23 2.3.4. Discrete sources.........................................................................................................................23 2.3.5. Radioactive contamination........................................................................................................23 2.4. The Potential Introduction of Discrete Sources in Metal Scrap ....................................................24 2.4.1. Primary and secondary metals production ................................................................................24 2.4.2. Designers, owners, operators and maintainers of plant and equipment ....................................25 2.4.3. Demolition of plant and discarding of equipment .....................................................................25 2.4.4. Scrap collectors and processors.................................................................................................25 2.5. The Potential for Contamination of Scrap by Radioactively Contaminated Material.................26 2.5.1. Primary and secondary metals production ................................................................................26 2.5.2. Designers, owners, operators and maintainers of plant and equipment.................................26 2.5.3. Demolition of plant and dismantling of equipment ...................................................................27 2.5.4. Scrap collectors and processors.................................................................................................27 2.6. Present Situation Regarding the Limitations of Radioactive Substances in Scrap ......................27 2.6.1. Regulatory requirements........................................................................................................27 2.6.2. Contractual specifications applied in the industry - Business acceptance limits ...................28 5 2.7. Responsibility in Case of Discovery of an Orphan Source or Radioactively Contaminated Material in Metal Scrap ................................................................................................................28 2.8. Paucity of Information ....................................................................................................................29 CHAPTER III. PREVENTION OF CONTAMINATION OF SCRAP THROUGH REGULATORY CONTROL ..................................................................................................................................................31 3.1. General............................................................................................................................................31 3.2. Prevention of Occurrence of Orphan Sources................................................................................32 3.3. Prevention of Radioactive Contamination......................................................................................33 3.4. Materials with Naturally Occurring Radioactive Materials..........................................................34 CHAPTER IV. DETECTION AND MONITORING OF RADIOACTIVE MATERIALS IN THE SCRAP WITHIN THE RECYCLING INDUSTRY..........................................................................37 4.1. General Approach...........................................................................................................................37 4.2. Factors Affecting Detection ............................................................................................................38 4.2.1. Radiation penetration................................................................................................................38 4.2.2. Background radiation................................................................................................................38 4.2.3. Methods of radiation detection ..................................................................................................39 4.3. General Considerations when Monitoring Metal Scrap for Radioactivity....................................39 4.4. Monitoring Points............................................................................................................................40 4.5. Fixed Monitoring Systems...............................................................................................................40 4.5.1. General features ........................................................................................................................40 4.5.2. Detection of the presence of a vehicle and speed measurement ................................................40 4.5.3. Detector heads ...........................................................................................................................41 4.5.4. Computing hardware/software...................................................................................................43 4.5.5. Alarm criteria and false alarms.................................................................................................43 4.5.6. Peripheral equipment ................................................................................................................44 4.5.7. Practical testing of system performance ....................................................................................44 4.5.8. Reliability ..................................................................................................................................46 4.6. Portable Detector Systems.............................................................................................................46 4.7. Visual Observation of the Scrap....................................................................................................47 CHAPTER V. ACTIONS TO RESPOND TO A DETECTION OF RADIOACTIVE