CONTENTS
SUMMARY ...................................................................................................................... 1
1. INTRODUCTION ................................................................................................... 3
1.1. BACKGROUND OF THE MODARIA PROGRAMME ......................... 3
1.2. THE REQUIREMENT FOR ADVANCED MODELS TO PREDICT
MARINE DISTRIBUTION OF RADIONUCLIDES AFTER LAND-
BASED ACCIDENTAL RELEASES ....................................................... 4
2. THE BALTIC SEA RADIOLOGICAL SCENARIO ............................................. 6
2.1. INTRODUCTION ..................................................................................... 6
2.2. DESCRIPTION OF THE BALTIC SEA .................................................. 6
2.2.1. Physical description ....................................................................... 6
2.2.2. Radionuclide inputs ..................................................................... 11
2.3. MODELLING EXERCISE ..................................................................... 12
2.3.1. Previous modelling studies .......................................................... 12
2.3.2. Model descriptions ....................................................................... 13
2.3.3. Modelling endpoints .................................................................... 13
2.4. RESULTS AND DISCUSSION .............................................................. 15
2.5. CONCLUSIONS ..................................................................................... 21
3. THE PACIFIC OCEAN RADIOLOGICAL SCENARIO .................................... 22
3.1. INTRODUCTION ................................................................................... 22
3.1.1. Previous modelling studies .......................................................... 22
3.1.2. Present modelling exercises and applied models ......................... 24
3.2. EXERCISE 1: INITIAL MODEL COMPARISON ................................ 25
3.2.1. Modelling exercise ....................................................................... 25
3.2.2. Results .......................................................................................... 25
3.3. EXERCISE 2: HOMOGENIZATION OF WATER CIRCULATION ... 29
3.3.1. Introduction .................................................................................. 29
3.3.2. Comparison of hydrodynamic fields............................................ 30
3.3.3. Quantitative comparison .............................................................. 32
3.3.4. Tracer dispersion .......................................................................... 37
3.3.5. 137Cs dispersion ............................................................................ 37
3.4. EXERCISE 3: HOMOGENIZATION OF WATER–SEDIMENT
INTERACTIONS .................................................................................... 43
3.4.1. Introduction .................................................................................. 43
3.4.2. Tracer dispersion .......................................................................... 44
3.4.3. 137Cs dispersion and no SPM in the water column ...................... 44
3.4.4. 137Cs dispersion and constant and uniform SPM distribution in the
water column ................................................................................ 45
3.5. EXERCISE 4: COMPARISONS WITH FIELD DATA ......................... 52
3.5.1. Source term .................................................................................. 52
3.5.2. Results .......................................................................................... 56
3.6. CONCLUSIONS ..................................................................................... 66
4. OVERALL SUMMARY AND CONCLUSIONS ................................................ 69
REFERENCES ................................................................................................................ 71
