Year
1999
Abstract
The Savannah River Site (SRS) has the analytical measurement capability to perform high-precision plutonium concentration measurements by controlled-potential coulometry. State-of-the-art controlledpotential coulometers were fabricated by the SRS Engineered Equipment and Systems Department and installed in the Analytical Laboratories’ process control laboratory. The Analytical Laboratories uses coulometry for routine accountability measurements of pure plutonium from the PUREX process and for verification of standard preparations used to calibrate other plutonium measurement systems routinely applied to process control, nuclear safety, and other accountability applications. The SRS Coulometer has a demonstrated measurement reliability of -0.05% for 10 mg samples. The system has also been applied to the characterization of neptunium standard solutions with a comparable reliability. The SRS coulometer features: a patented current integration system; continuous electrical calibration versus Faraday’s Constants and Ohm’s Law; the control-potential adjustment technique for enhanced application of the Nemst Equation; a wide operating room temperature range; and a fully automated instrument control and data acquisition capability. The system has been operated for 10 years with minimal equipment failures and downtime. The coulometer and instrument controller have been periodically upgraded to remain current with available high-precision potential control and current integration components. A stability of f 0.0015% RSD for the electronic calibration factor has been demonstrated. Most recently the system was converted from a Hewlett Packard computer platform to an IBM Computer / Windows based system.