PLUTONIUM ASSAY USING SUPERHEATED DROP TECHNOLOGY IN SUPPORT OF INTERNATIONAL ATOMIC ENERGY AGENCY SAFEGUARDS

THE END OF THE COLD WAR HAS SWITCHED THE FOCUS FROM BUILDING WEAPONS OF DETERRENCE TO MINIMIZING THE CHANCES FOR THE USE OR PROLIFERATION OF NUCLEAR WEAPONS. THUS, ARMS CONTROL VERIFICATION AND THE CAREFUL MONITORING OF THE NUCLEAR NON-PROLIFERATION TREATY ARE ESSENTIAL COMPONENTS OF ANY INTERNATIONAL EFFORT TO ASSURE SAFETY FROM NUCLEAR THREATS AND SECURITY AROUND THE WORLD. SUCCESS IN VERIFICATION AND MONITORING ARE ONLY POSSIBLE IF INSTRUMENTATION HAS ADEQUATE SENITIVITY FOR THE RADIATION TYPE OF INTEREST AND GIVES AN UNAMBIGUOUS AND IMMEDIATE READOUT. THERE ARE PRACTICAL REQUIREMENTS AS WELL. THE INSTRUMENTATION SHOULD BE READILY PORTABLE, SHOULD BE EASY-TO-USE, AND SHOULD SAVE THE RADIATION FLUENCE HISTORY FOR LATE ANALYSIS. IT SHOULD COMPLEMENT OTHER INSTRUMENTATION DESIGNED TO SUPPORT THE SAFEGUARDS PROGRAM OF THE INTERNATIONAL ATOMIC ENERGY AGENCY. SUPERHEATED DROP (BUBBLE) TECHNOLOGY (SDD) PROMISES SUCH CHARACTERISTICS AND OVERCOMES SOME OF THE LIMITATIONS OF GAMMA SPECTROMETRY AND (3)HE COINCIDENCE COUNTING. PHASE I CONSISTS OF THE RESEARCH AND DEVELOPMENT THAT WILL CONSIDER THE FEASIBILITY OF A SMALL, MICROPROCESSOR-BASED NEUTRON SPECTROMETER THAT WILL COUNT BUBBLE EVENTS PRODUCED BY NEUTRONS. SPECTROMETRY WILL BE ACCOMPLISHED BY USING SDD COMPOSITIONS POSSESSING DIFFERENT NEUTRON ENERGY THRESHOLDS. THIS SYSTEM WILL COMPLEMENT GAMMA SPECTROMETRY IN PROVIDING IMMEDIATE DISPLAY OF THE RADIATION FLUENCE AND FLUX AS WELL AS IMMEDIATE OR DELAYED DOWNLOADING OF THE RADIATION RECORD TO A COMPACT, BATTERY-POWERED PERSONAL COMPUTER. FROM SUCH RECORDS, ON-SITE INSPECTORS SHOULD BE ABLE TO MAKE REASONABLE ASSAYS OF THE AMOUNT OF PLUTONIUM PRESENT, WITH THE POSSIBILITY OF DIFFERENTIATING BETWEEN SPONTANEOUS FISSION NEUTRONS AND NEUTRONS PRODUCED BY ALPHA-N REACTIONS. THE ENTIRE SYSTEM, WHICH SHOULD FIT IN AN ATTACHE-SIZED CASE, MAY ALSO FIND APPLICATION IN LOW-LEVEL ENVIRONMENTAL MONITORING OF TRANSURANIC WASTES.