Managing potentially radioactive scrap metal : recommendations of the National Council on Radiation Protection and Measurements.

Preface ........................................................................................ iii 1. Executive Summary ........................................................... 1 2. Introduction ......................................................................... 11 2.1 Background ...................................................................... 11 2.2 Purpose and Scope of this Report .................................. 12 2.3 Management Considerations .......................................... 13 2.4 Clearance Concept and Framework ............................... 14 2.5 Control of Orphan Sources and the Impact on Clearance ......................................................................... 15 2.6 Disposition Strategy ........................................................ 15 2.7 Report Structure .............................................................. 16 3. Sources, Inventories and Characteristics of Potentially Radioactive Scrap Metal ............................. 18 3.1 Sources of Scrap Metal ................................................... 18 3.1.1 Nuclear Activities ................................................. 18 3.1.2 Non-Nuclear Activities Associated with Radioactive Materials ........................................... 19 3.2 Inventories and Radiological Characteristics ................ 20 3.2.1 Overview ................................................................ 20 3.2.2 Commercial Nuclear Power Plants ..................... 22 3.2.2.1 Pressurized Water Reactors ................... 26 3.2.2.2 Boiling Water Reactors ........................... 27 3.2.3 DOE Nuclear Weapons Facilities ........................ 28 3.2.3.1 Uranium Enrichment Facilities ............. 30 3.2.3.2 Uranium Metal Production Facilities .... 32 3.2.3.3 Production Reactors ................................ 32 3.2.3.4 Nuclear Fuel Reprocessing Facilities .... 32 3.2.3.5 Other DOE Facilities .............................. 33 3.2.4 Defense Nuclear Facilities ................................... 33 3.2.5 Research and Test Reactors and Accelerators .... 34 3.2.6 Industrial Facilities Involved with Naturally Occurring Radioactive Materials ......................... 35 3.3 Metal Availability ............................................................ 36 v vi / CONTENTS 4. Management Considerations ........................................... 38 4.1 Current Laws, Regulations and Policies ....................... 38 4.1.1 Regulatory Overview ............................................ 38 4.1.2 Potentially Radioactive Scrap Metal as Radioactive Waste or Mixed Waste ..................... 42 4.1.3 Waste Minimization ............................................. 44 4.2 Disposition Considerations ............................................. 45 4.2.1 Characterization ................................................... 46 4.2.1.1 Process History ........................................ 46 4.2.1.2 Inference from Measurements ............... 47 4.2.1.3 Direct Measurement of Potentially Radioactive Scrap Metal ......................... 47 4.2.2 Setting Disposition Priorities ............................... 47 4.2.3 Current Practices .................................................. 49 4.2.3.1 Release to General Commerce .............. 50 4.2.3.2 On-Site Storage ....................................... 51 4.2.3.3 Recycle for Internal Use ......................... 51 4.2.3.4 Disposal at Resource Conservation and Recovery Act Landfills ............................ 52 4.2.3.5 Disposal at Licensed Low-Level Radioactive Waste Facilities .................. 53 4.2.3.6 Case Examples ........................................ 53 4.3 Factors Influencing Management Decisions ................ 55 4.3.1 Regulatory Needs and Recent Policy-Making Activities ................................................................ 57 4.3.2 Cost Considerations .............................................. 59 4.3.3 Treatment Options ............................................... 60 5. Developing Release Standards ........................................ 63 5.1 Radiation Protection Framework ................................... 63 5.1.1 Overview ................................................................ 63 5.1.2 System of Protection for Practices ....................... 64 5.1.2.1 Justification of Practice .......................... 64 5.1.2.2 Optimization of Protection ...................... 64 5.1.2.3 Protection of Individuals ......................... 66 5.1.2.4 Potential Exposures ................................ 66 5.1.3 System of Protection for Intervention ................. 66 5.1.3.1 Justification of Intervention ................... 66 5.1.3.2 Optimization of Intervention .................. 67 5.2 Concepts for Controlling Release ................................... 67 5.2.1 Control Not Imposed Through Deliberation— Exemption ............................................................. 67 5.2.2 Control Removed by Authorization—Clearance ... 68 CONTENTS / vii 5.2.3 Control Deemed Unnecessary Due to Trivial Risk—de Minimis ................................................. 69 5.3 Role of Clearance in Waste Management .................... 71 5.4 Development of Clearance Standards ............................ 72 5.4.1 Dose Assessment ................................................... 73 5.4.1.1 Dose Constraints ..................................... 73 5.4.1.2 Clearance Alternatives and Scenarios ... 74 5.4.1.3 Exposure Considerations ........................ 75 5.4.1.4 Assessment Approach ............................. 76 5.4.1.5 Probabilistic Approach to Estimating Model Uncertainties ................................ 77 5.4.1.6 ‘‘As Low As Reasonably Achievable’’ Considerations ......................................... 77 5.4.1.7 Potential Exposures ................................ 78 5.4.2 Recent Activities ................................................... 78 5.4.2.1 IAEA ......................................................... 79 5.4.2.2 NEA .......................................................... 80 5.4.2.3 EC ............................................................. 81 5.4.2.4 ANSI/HPS ................................................ 81 5.4.3 Current Issues Regarding Standards Development .......................................................... 83 6. Radiation Protection in Scrap Metal Recycling ......... 87 6.1 Overview of Scrap Metal Markets ................................. 87 6.1.1 Scrap Metal as a Commodity ............................... 87 6.1.2 Sources of Scrap Metal ......................................... 89 6.1.3 Circulation of Scrap Metal ................................... 90 6.1.3.1 Background .............................................. 90 6.1.3.2 Collection ................................................. 91 6.1.3.3 Scrap Processing ...................................... 92 6.1.3.4 Broker/Dealers ......................................... 92 6.2 Sources of Radioactive Materials in Scrap Metals ....... 93 6.2.1 Naturally Occurring Radioactive Materials ....... 93 6.2.2 Refractory Wear Sources ...................................... 94 6.2.3 Inadvertent Melting of Sealed Sources ............... 94 6.3 Distribution of Radioactive Material in the Metal- Melting Process .............................................................. 95 6.3.1 Background ........................................................... 95 6.3.2 Partitioning of Radionuclides .............................. 97 6.4 Radiation Protection Issues ............................................ 101 6.4.1 Exposure Scenarios ............................................... 101 6.4.1.1 Activities at Generator Sites .................. 101 6.4.1.2 Steel Plant Activities .............................. 102 6.4.1.2.1 Scrap Handling ........................ 102 6.4.1.2.2 Melt Shop ................................. 103 6.4.1.2.3 Slag Workers ........................... 105 viii / CONTENTS 6.4.1.2.4 Rolling Mill/Crane/Forklift/ Load Dock/Maintenance Workers .................................... 106 6.4.1.2.5 Baghouse Operations .............. 106 6.4.1.2.6 Metal Cleaning ........................ 107 6.4.1.3 End-Use Consumers ................................ 107 6.4.1.4 Environmental Releases ......................... 107 6.4.2 Potential Exposure Pathways to Metal Processors .............................................................. 108 6.5 Public Concerns Over Radioactive Contamination ....... 109 7. Protection Against Orphan Source Contamination ... 111 7.1 Overview of the Orphan Source Problem ...................... 111 7.1.1 Discovery of Radioactive Sources in Steel Mills ... 112 7.1.2 Response by Industry ........................................... 112 7.1.3 Scope of the Issue ................................................. 114 7.2 Origins of Orphans Sources ............................................ 115 7.2.1 Licensure of Radioactive Devices ........................ 116 7.2.1.1 Specific Licensure .................................... 116 7.2.1.2 General Licensure ................................... 118 7.2.1.3 Exemptions .............................................. 118 7.2.2 Origin of Orphan Sources .................................... 119 7.2.3 Management Challenges ...................................... 119 7.3 Managing Contamination ............................................... 121 7.3.1 Events and Impacts .............................................. 121 7.3.2 Control of Licensed Devices ................................. 122 7.3.3 Source Detection ................................................... 123 7.3.3.1 Methods of Detection .............................. 123 7.3.3.2 Effectiveness of Detection ....................... 125 7.3.3.3 Cost Constraints on Detection ............... 126 7.3.3.4 Impact of Detection Systems on Potentially Radioactive Scrap Metal Clearance ................................................. 127 7.4 Needed Enhancements in Regulatory Control .............. 127 7.4.1 Preventive Measures ............................................ 127 7.4.1.1 Improving the Licensing System ........... 128 7.4.1.2 Developing a National Tracking System ...................................................... 130 7.4.1.3 Facilitating Source Collection and Disposition ............................................... 130 7.4.1.4 Imposing Financial Surety ..................... 132 7.4.2 Corrective Measures ............................................. 133 7.4.2.1 Improving Detection Capability ............. 133 CONTENTS / ix 7.4.2.2 Developing Protocols for Discovery, Reporting and Transporting Radioactive Sources ................................ 134 7.4.2.3 Creating Interim Repositories ................ 135 7.5 Government-Industry Collaboration .............................. 135 8. Findings and Recommendations ..................................... 138 8.1 Findings ........................................................................... 138 8.1.1 Management and Disposition of the Large Amounts of Potentially Radioactive Scrap Metal Generated in the United States Will Require a Comprehensive and Multifaceted Approach ....... 138 8.1.2 National Guidance on Pollution Prevention Forms a Sound Basis for Potentially Radioactive Scrap Metal Management ............... 139 8.1.3 Current Regulatory System Focuses Only on Waste Management .............................................. 139 8.1.4 There is an Urgency to Establish Consistent National/International Policies and Standards .. 140 8.1.5 Concerns of the Metal Industry and the Public Must be Adequately Addressed ........................... 141 8.2 Recommendations ............................................................ 141 8.2.1 Comprehensive and Consistent National and International Risk-Based Policies for Managing Potentially Radioactive Scrap Metal Need to be Developed .............................................................. 142 8.2.2 A Set of Uniform Clearance Standards to Address National and International Concerns Needs to be Developed .......................................... 143 8.2.3 Standards Should Include Naturally Occurring Radioactive Material and Technologically Enhanced Naturally Occurring Radioactive Material ................................................................. 144 8.2.4 Regulatory Control Over Orphan Sources Must be Improved ........................................................... 145 8.2.5 The Process of Clearance and Intervention/ Interception Should be Harmonized .................... 147 8.2.6 The Use of Licensed Mills/Brokerages as ‘‘Clearing Houses’’ for Recycling Should be Encouraged ............................................................ 147 8.2.7 New Technologies and/or Plant Designs to Reduce Contamination Should be Developed ..... 148 8.2.8 Steps Should be Taken to Enhance Public Understanding of the Clearance Process ............ 148 x / CONTENTS Appendix A. Metal-Making Technology ............................. 151 A.1 Scrap Collection ............................................................ 151 A.2 Scrap Processing ........................................................... 153 A.3 Scrap Consumers .......................................................... 154 A.4 Metal-Making Processes and Technology ................... 154 A.4.1 Iron-Making Technology .................................... 154 A.4.1.1 Blast Furnaces ..................................... 154 A.4.1.2 Electric Arc Furnaces .......................... 156 A.4.1.3 Cupolas and Induction Furnaces ........ 156 A.4.2 Steelmaking Technology .................................... 156 A.4.2.1 Basic Oxygen Process .......................... 156 A.4.2.2 Electric Arc Furnaces .......................... 158 A.4.2.3 Induction Furnaces .............................. 160 A.4.2.4 Impact of Melting Radioactive Scrap ... 161 A.4.3 Primary Processing ............................................ 163 A.4.3.1 Ingot Casting ........................................ 163 A.4.3.2 Continuous Caster ............................... 163 A.4.3.3 Pressure Casting .................................. 165 A.4.4 Finishing Processes ............................................ 165 A.5 Aluminum Manufacturing ........................................... 166 A.6 Copper, Bronze and Brass Manufacturing ................. 166 A.7 Nickel Manufacturing .................................................. 167 Appendix B. Radiation Detection and Surveillance ...... 168 B.1 Surveillance at Generator Sites .................................. 168 B.2 Monitoring at Scrap Yards and Mills ......................... 169 B.3 Monitoring Locations at Scrap Yards and Mills ........ 170 B.3.1 Portal Monitoring ............................................... 171 B.3.2 In-Plant Monitoring Systems ............................ 173 Glossary ...................................................................................... 177 Acronyms and Abbreviations ................................................ 188 References ................................................................................. 189 The NCRP .................................................................................. 202 NCRP Publications .................................................................. 211 Index ........................................................................................... 221