Investigation of a possible basis for a common approach with regard to the restoration of areas affected by lasting radiation exposure as a result of past or old practice or work activity CARE Investigation of a possible basis for a common approach with regard to the restoration of areas affected by lasting radiation exposure as a result of past or old practice or work activity CARE Final Report Prepared by Hildegarde Vandenhove1, Andrew Bousher2, Per Hedemann Jensen3, Duncan Jackson2, Barbara Lambers2, Theo Zeevaert1. 1SCK•CEN, Department of Radiation Protection, Boeretang 200, B-2400 Mol, BELGIUM. 2Westlakes Scientific Consulting Ltd, Westlakes Science and Technology Park, Moor Row, Cumbria, CA24 3LN, UNITED KINGDOM. 3Risø National Laboratory, Department of Safety, DK-4000, DENMARK. For European Commission DG XI Environment, Nuclear Safety and Civil Protection under contract 96-ET-006 September 1999 Foreword The scope of the CARE project (Common Approach for Restoration of contaminated sites) is to develop a basis for policies in view of restoring areas contaminated as a result of past practices and work activities involving naturally occurring radionuclides (NOR). Until recently, regulators have paid little attention to the radiation protection issues associated with such sites. The new Basic Safety Standards1, for the health protection of the general public and workers against the dangers of ionizing radiation, include provisions for situations leading to lasting exposure under Title IX – Intervention. The present document is the final report of a study conducted by a consultant (SCK- CEN, contract 96-ET-006), comprising an identification of the areas of concern, a methodology for radiological assessment, a characterisation of different restoration options in terms of performance and cost, and a decision aiding framework using multi- attribute utility functions as well as action levels for intervention referring to international guidance. The outcome of the study was thoroughly discussed by a working party of the Group of Experts established under Article 31 of the Euratom Treaty, thus also providing quality assurance and editorial improvements. The study will further be used as a working document in view of the establishment of general guidance to Member States on approaches for dealing with lasting exposure situations. This may extend to situations other than those resulting from work activities involving NOR, in particular in the event of areas contaminated as a result of a radiological emergency. S. Kaiser 1 Directive 96/29/EURATOM i Abstract The scope of the CARE project (Common Approach for Restoration of contaminated sites) is to develop a basis for policies in view of restoring areas contaminated as a result of past practices and work activities involving naturally occurring radionuclides (NOR). The present document is the final report of a study conducted by a consultant (SCK- CEN, contract 96-ET-006), comprising an identification of the areas of concern, a methodology for radiological assessment, a characterisation of different restoration options in terms of performance and cost, and a decision aiding framework using multi- attribute utility functions as well as action levels for intervention referring to international guidance. ii Acknowledgements The authors of this report wish to express their gratitude to the people who have contributed to the completion of this project. In particular, the persons who have supplied information for the inventory of past practices in different European countries and who are mentioned as 'personal communications' in Annex A2. More specifically, we would like to thank G. Henze and K. Wichterey from the Bündesambt für Strahlenschutz, Berlin, for the detailed information on the Mansfeld and Freital sites. Furthermore, we would also like to thank A.D. Smith and G. Smith of Westlakes Scientific Consulting Ltd for their respective contributions to the radiological evaluation and to the Crystal Ball analysis. Finally, the personnel of organisations who have provided information on the regulations in different European countries are recognised. iii Table of Contents 1. SCOPE AND LIMITATIONS OF THE STUDY 1 1.1 Scope 1 1.2 Limitations 1 2. EXECUTIVE SUMMARY 2 2.1 Identification of areas of concern 2 2.2 Assessment 3 2.3 Remediation options 3 2.4 Derivation of criteria and selection of remediation options 4 3. DEALING WITH NOR CONTAMINATED SITES 5 4. DESCRIPTION AND INVENTORY OF INDUSTRIES EXTRACTING AND PROCESSING NORM 6 4.1 Occurrence of enhanced levels of naturally occurring radioactive materials (NORM) 6 4.2 Categorisation of NOR-contaminated sites 8 4.2.1 Uranium mining and milling 9 4.2.2 Metal mining and smelting 10 4.2.3 Phosphate industry 10 4.2.4 Coal mining and power production from coal 11 4.2.5 Oil and gas drilling 11 4.2.6 Rare earth and titanium oxide industries 11 4.2.7 Zirconium and ceramics industries 12 4.2.8 Disposal of building materials 12 4.2.9 Application of radium and thorium 12 4.3 References 16 5. GENERIC RADIOLOGICAL ASSESSMENT APPLIED TO A PHOSPHATE GYPSUM DUMP AS EXAMPLE CASE 17 5.1 Introduction 17 5.2 Summary description of AMCARE - the assessment model for CARE 18 5.3 Assessment for Tessenderlo 19 5.3.1 Site description 19 5.3.2 Model parameters 20 5.3.3 Local residency critical group exposure 26 5.3.4 Intrusion scenario critical group exposure 29 5.3.5 Workforce exposure 31 5.3.6 Collective dose 34 5.4 Discussion 37 5.4.1 Radionuclides and pathways of major importance 37 5.4.2 Effect of parameter uncertainty 37 iv 5.5 Conclusions 38 5.6 References 38 6. REMEDIATION OPTIONS 39 6.1 Introduction 39 6.2 Remediation options 40 6.3 Selection of remediation technologies for a contaminated site 44 6.4 Application of remediation technologies to a contaminated site 44 6.4.1 Remediation effects on the critical group dose at Tessenderlo 45 6.4.2 Remediation effects on the collective dose at Tessenderlo 45 6.4.3 Workforce dose during remediation activity 46 6.4.4 Cost of remediation based on the Tessenderlo site 48 6.4.5 Fractional removal of contaminant material 48 6.5 Discussion 49 6.6 References 50 7. DERIVATION OF CRITERIA AND SELECTION OF REMEDIATION OPTIONS 51 7.1 Introduction 51 7.2 Methodology for selection of remedial measures 51 7.2.1 Normalised Action Levels for remedial measures 51 7.2.2 Optimisation of remedial measures 54 7.3 Assessments of remediation strategies for a selected European site 56 7.3.1 Action Levels for a phosphate industry site 57 7.3.2 Optimisation of remedial measures for a phosphate industry site 60 7.4 Conclusions 66 7.5 References 68 ANNEX A1 DESCRIPTION OF INDUSTRIES DEALING WITH NORMS: GENERAL BACKGROUND, INDUSTRIAL PROCESSES, CONTAMINATION LEVELS, MAJOR RELEASE ROUTES AND PATHWAYS 69 ANNEX A2 OVERVIEW OF CONTAMINATED SITES IN EUROPE 105 ANNEX B1 AN OVERVIEW OF COMPUTER-BASED MODELLING APPROACHES FOR RADIOACTIVE WASTE SITES 133 ANNEX B2 A TECHNICAL DESCRIPTION OF AMCARE 153 ANNEX B3 INTERCOMPARISON OF THE DOSE PREDICTIONS OBTAINED WITH THE GENERIC MODEL, AMCARE, WITH THOSE OBTAINED FROM A MODEL SPECIFIC TO THE TESSENDERLO SITE 177 ANNEX C1 OVERVIEW OF REMEDIATION TECHNOLOGIES 183 ANNEX D1 OVERVIEW OF REMEDIATION CRITERIA FROM INTERNATIONAL ORGANISATIONS 195 v ANNEX D2 OVERVIEW OF CRITERIA FOR REMEDIAL MEASURES IN DIFFERENT COUNTRIES 207 ANNEX D3 JUSTIFICATION AND OPTIMISATION OF PROTECTION 219 ANNEX D4 METHODOLOGY FOR DETERMINING ACTION LEVELS FOR REMEDIAL MEASURES 230 vi 1. SCOPE AND LIMITATIONS OF THE STUDY 1.1 Scope The scope of the CARE project (Common Approach for REstoration of contaminated sites) is to develop a basis for a common approach to restoring areas affected by lasting radiation exposure from natural radionuclides. The sites considered are areas contaminated as a result of past practices or work activities. These may include activities which may not have been classified as 'of radiological concern' or which may be subject to site licensing for disposal of radioactive materials based on contemporary criteria. Enhanced levels of naturally occurring radionuclides (NORs) may be associated with abandoned waste dumps, installations and surroundings from certain industries, involved in the extraction or processing of raw materials containing NORs. This can result in considerable exposure to the public. Until recently, regulators have paid little attention to the radiation protection issues associated with these sites. This study provides a basis for conceptualising and quantifying the extent of the radiation problem caused by residues from past activities of NOR-extraction and processing industries at a European scale, and also provides a basis for the relevant national and European authorities to set directives and regulations for the protection of the general public to radiation exposure of this origin. The study is subdivided into four main parts: • Identification of areas of concern: categorisation of industries handling NOR-containing material; overview of sites in Europe contaminated with residues from the industries considered. • Radiological assessment: elaboration of an appropriate assessment methodology for existing conditions and with extrapolation to future normal evolution and intrusion scenarios. • Restoration options: characterisation and evaluation of remediation techniques in terms of performance, costs and social implications using a cost-effectiveness and multi-attribute utility decision aiding framework. • Intervention levels: overview of restoration criteria; proposition of methodology for deriving action levels and criteria. 1.2 Limitations There are a large number of non-radiological contaminants which can occur in the uranium tailings and other NOR-containing wastes which can be mobilised under acidic conditions and appear in seepage, including heavy metals, rare earths, salts and nutrients. Since the non- radiological pollutants in some of the wastes can present as great a hazard to the environment as the radiological pollutants, both must be taken into account and factored into the safe management of waste.