REMEDIATION OF SITES WITH DISPERSED RADIOACTIVE

1,32

MB

CONTAMINATION

125

stron

2484

ID

International Atomic Energy Agency

2004

rok

CONTENTS

1. INTRODUCTION . 1

1.1. Background 1

1.2. Scope 6

1.3. Structure . 6

2. DISPERSED RADIOACTIVE CONTAMINATION 6

3. FACTORS INFLUENCING TECHNOLOGY SELECTION 8

3.1. Fundamental technical choices 8

3.2. Technology sources 10

3.3. Effectiveness . 11

3.4. Cost . 12

3.5. Occupational safety and health 12

3.6. Secondary environmental impacts 13

3.7. Prior experience . 13

3.8. Socioeconomic considerations . 14

4. NON-INTERVENTION 14

4.1. Basic considerations . 14

4.2. Dilution and dispersion . 15

4.3. Natural attenuation 15

4.3.1. Principles 15

4.3.2. Physical processes . 16

4.3.2.1. Radioactive decay . 16

4.3.2.2. Filtration . 16

4.3.2.3. Volatilization . 16

4.3.3. Chemical processes 18

4.3.3.1. Precipitation 18

4.3.3.2. Co-precipitation 18

4.3.3.3. Sorption . 19

4.3.3.4. Complexation by organics 19

4.3.4. Biological processes . 20

4.3.5. Definitions and applicability 20

4.4. Alternative land uses . 21

4.5. Agricultural countermeasures . 26

5. CONTAINMENT 29

5.1. Enhanced attenuation . 29

5.2. Low permeability barriers 30

5.3. Permeable reactive barriers . 31

5.4. Immobilization 38

5.5. Biological barrier walls (biowalls) 40

5.6. Phytostabilization . 42

5.7. Constructed wetlands 45

6. REMOVAL . 49

6.1. Preconditions and constraints . 49

6.2. Immobilization and solidification (ex situ) . 49

6.3. Surface and groundwaters: pump and treat 50

6.4. Enhanced recovery 52

6.5. Chemical extraction (ex situ) 54

6.6. Hydrometallurgical methods 55

6.7. Segregation . 56

6.8. Biosorption . 56

6.9. Bioleaching . 59

6.10. Phytoextraction . 63

6.10.1. Overview 63

6.10.2. Uranium removal . 67

6.10.3. Strontium removal 68

6.10.4. Caesium removal 69

6.10.5. Phytoextraction project in Belarus . 71

6.11. Rhizofiltration 72

7. SUMMARY AND CONCLUSIONS . 75

REFERENCES 79

GLOSSARY . 115

CONTRIBUTORS TO DRAFTING AND REVIEW . 117