Smart Unattended Systems for Plutonium Safeguards

During the past decade, International Atomic Energy Agency (IAEA) inspectors, national inspectors, and facility operators have used neutron coincidence countem’~ and gamma-ray isotopics measurements extensively to measure the plutonium content of various forms of nuclear materials in the fiel cycle. Of special importance for these verification measurements are the input, output and in-process inventory of nuclear fuel fabrication facilities. Large automated facilities for fabricating plutonium fuel present both difilculties and challenges for improved accounting of nuclear materials. The traditional methods of sample measurements, requiring the transfer of the sample from the production line to the assay measurement station, are not possible in automated facilities. The robotics used for automation require special containers for nuclear material that cannot be easily removed from the production line. Safety and radiation protection considerations also require that the assay instmmentation be installed in the fuel production lines because, in general, personnel cannot be in the fuel-handling area with nuclear material during operations. Such operational constraints are common in many of the modem facilities that have been designed for fabricating and processing plutonium fuel.