PRIMARY COOLANT RADIONUCLIDE CHARACTERIZATION, MODELLING AND REDUCTION

A MAJOR BARRIER TO EXTENDING THE BURNUP OF LIGHT WATER REACTOR FUEL IS THE BUILDUP OF FISSION PRODUCTS IN THE REACTOR COOLANT, WHICH MAY APPROACH PLANT CHEMISTRY OR EFFLUENTS TECHNICAL SPECIFICATIONS NEAR THE END OF CORE LIFE. IT IS PROPOSED TO USE CURRENTLY INSTALLED AUTOMATED ISOTOPIC REACTOR COOLANT ASSAY SYSTEMS AT UP TO FOUR OPERATING NUCLEAR POWER REACTORS TO EXPLORE THE RELATIONSHIPBETWEEN ANTICIPATED AND UNANTICIPATED OPERATIONAL MANEUVERS AND OBSERVED COOLANT CONCENTRATIONS. IN PHASE I, AN EXTENSIVE DATABASE OF CONCENTRATIONS MEASURED AT NEAR-CORE TEMPERATURES AND PRESSURES, AND OF ASSOCIATED OPERATIONAL PARAMETERS WILL BE DEVELOPED AT THE PARTICIPATING POWER PLANTS. THE DATA WILL BE TRANSFERRED TO NUCLEAR DATA FACILITIES, ANALYZED FOR CORRELATIONS, AND COMPARED WITH RESULTS OF FISSION PRODUCT MODELS NOW IN USE. THE PHASE I FINAL REPORT WILL INCLUDE SELECTED CONCENTRATION DATA AND ALL OBSERVED CORRELATIONS. PHASES II AND III WILL BE DEVOTED TO THE APPLICATION OF PHASE I DATA TO IMPROVEMENTS IN MODELLING OF FISSION PRODUCT ACTIVITY IN THE REACTOR COOLANT, TESTS OF THE ABILITY TO DETECT AND LOCALIZE FAILED FUEL, AND ATTEMPTS TO INFER PROPER OPERATIONAL MANEUVERS TO AVERT OR MINIMIZE RADIOACTIVITY LEAKAGE FROM FAILED FUEL ELEMENTS. THE PHENOMENON OF SPIKING WILL BE STUDIED IN DETAIL.