OPTICAL SENSOR FOR DETECTION OF SODIUM LEAK FROM A POOL-TYPE LIQUID METAL COOLED REACTOR VESSEL

EARLY DETECTION OF SODIUM LEAKAGE FROM THE POOL-TYPE LIQUID METAL COOLED REACTOR (LMR) VESSEL IS AN IMPORTANT SAFETY ISSUE. AN INTRINSICALLY SAFE AND FAST MEANS OF DETECTION IS REQUIRED FOR SODIUM LEAKAGE IN THE GAP BETWEEN THE REACTOR AND GUARD VESSELS. AT THE OPERATING PRESSURE AND TEMPERATURE OF THE REACTOR, THE SODIUM IS EXPECTED TO LEAK IN THE FORM OF BOTH LIQUID AND VAPOR. AN OPTICAL SENSOR WILL BE DEVELOPED USING FIBER OPTICS FOR REAL-TIME MONITORING OF THE SODIUM VAPOR CONCENTRATION IN THE INERT (ARGON) GAS-FILLED CONTAINMENT VESSEL. THE SODIUM CONCENTRATION MEASUREMENT IS BASED ON THE ABSORPTION SPECTROSCOPY TECHNIQUE WITH A RESOLUTION OF 10 PARTS PER BILLION (PPB). THE FEASIBILITY OF THE CONCEPT WILL BE ESTABLISHED IN PHASE I OF THE PROJECT, INCLUDING THE DESIGN,FABRICATION, AND CALIBRATION OF A LABORATORY SCALE OPTICAL SENSOR FOR DETECTION OF SODIUM LEAKS. PHASE II OF THE PROJECT WILL INCLUDE THE DESIGN, FABRICATION, INSTALLATION, AND EVALUATION OF A NUMBER OF PROBES WITHIN A REALISTIC TEST ENVIRONMENT.