Overview of Density Meters Used at SRP for Sample Validation

For the process control laboratory, the verification of sample integrity prior to analysis is a critical prerequisite for reliable analytical measurements. At the Savannah River Plant (SRP), density check systems are employed to verify that samples are representative of respective process tank solutions. A wide array of Mettler density meters is used. With respect to temperature control, water-bath thermostat ted, electronically thermos tatted, and temperaturecorrected density meters have proven useful. Also, density meters with measurements precise to four, five, and six decimal places are required to meet overall sample validation needs. Remote density cells are used to facilitate density measurements in radiobenches, glove boxes and shielded cells. The selection of a density meter system for a specific sample validation application depends on numerous factors including: precision required; type of containment; radiation levels; exposure to corrosive chemicals; and range of density measurements required. Temperature-corrected density meters have proven very useful for achieving measurements precise to five decimal places under conditions where the use of water baths is not safe, and the use of sensitive electronic components is not practical. Computer software is used to correct for ambient temperature changes in the density measuring cell. An automated six-place density meter is now in use for validating dilute uranium product samples. Customized software is used to determine the error of density measurements as well as sampling error.