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IT IS EXPECTED THAT THIS EXPERIMENTAL PROGRAMME WILL CLARIFY IMPORTANT ASPECTS OF THE PHENOMENA UNDERLYING RE-ENTRAINMENT AND REVOLATILIZATION FROM SUMP WATER.
THE RESULTS WILL BE UTILIZED TO VERIFY A MODEL OF THESE PHENOMENA TO BE INCORPORATED INTO FP/AEROSOL BEHAVIOUR CODES IN REACTOR CONTAINMENTS.
THE OBJECTIVE OF THE PROPOSED RESEARCH IS TO DEVELOP AND TO APPLY TO SOURCE TERM CALCULATIONS A MECHANISTIC MODEL OF REVOLATILIZATION OF FISSION PRODUCTS FROM THE SUMP POOL IN A LWR DURING SEVERE ACCIDENTS. THE MODEL SHALL CONTAIN BOTH THE MECHANISMS OF RE-ENTRAINMENT AND RESUSPENSION IN A GENERALIZED FORMULATION AND SHALL BE APPLICABLE IN THE FULL RANGE OF CONDITIONS THAT MAY OCCUR DURING A CORE MELT ACCIDENT IN A LWR.
THE MODEL IS TO BE BASED ON RELEASE FRACTIONS AND SIZE SPECTRA WHICH ARE DETERMINED IN AN EXPERIMENTAL PROGRAMME ACCOMPANYING THE MODELLING WORK. AN EXPERIMENTAL VERIFICATION OF THE MODEL FORMS THE FINAL STEP OF THE DEVELOPMENT.
FINALLY THE APPLICATION OF THE MODEL TOGETHER WITH THE AEROSOL BEHAVIOUR CODE NAUA TO TYPICAL CORE MELT ACCIDENT SCENARIOS IS CARRIED OUT TO DETERMINE THE CONTRIBUTION OF REVOLATILIZATION PHENOMENA TO THE RADIOLOGICAL SOURCE TERM.