Year
1994
Abstract
Bubble-tube manometry is the most accurate currently available method for precision volumetric measurements of solutions in process tanks containing special nuclear materials. Bubble tubes installed in the accountability tank by the facility operator are instrumented with a precision pressure transducer and a programmable pneumatic multiplexing system. In a process-solution measurement technique currently under development, a spike solution containing a known amount of lutetium is added to the accountability tank, appropriate measures are taken to homogenize the tank contents, and a sample of the homogenized solution is analyzed by isotopic dilution mass spectrometry. Each method offers unique advantages when applied to independent verification of the special nuclear material content of process solutions for the purposes of international safeguards. The methods are compared with regard to attributes such as intrusiveness, authentication independent of the facility operator, value for process operations, suitability for continuous unattended process monitoring, technical implementation challenges, accuracy, inspection effort and cost. A solution-volume verification procedure emphasizing the complementary aspects of both methods is proposed. Application to the important process-solution measurement and verification needs in international safeguards is analyzed, and its advantages are clearly identified.