Year
2016
Abstract
The Off-Site Source Recovery Project (OSRP) is developing a gamma spectroscopy capability to obtain radionuclide composition and activity of unknown, orphaned sources. To qualify the program, a Quality Assurance Project Plan (QAPP) is being developed. The importance of establishing a QA program is to ensure that radiological and non-radiological measurements in support of the radiological characterization program are valid and of a defined quality. A well-established program can identify errors in measurement processes and maintain confidence in the results of the monitoring program. To ensure personnel qualifications, the OSRP-QAPP has outlined qualification and requalification processes such as analysis of blind samples for the participating individuals. Establishing the error boundaries of gamma spectroscopy analysis performed by the individuals to ensure personnel’s capabilities was done by examining three common error parameters. The total one-sigma uncertainty of +23% came from error resulting in measuring the distance of the source from the detector; the geometry and resulting attenuation error; and the systematic or bias error that was observed by analysis of several known samples. In addition, a replicate analysis was performed to assess the variability that occurs when multiple analysts analyze the same spectral data. This was performed in order to establish acceptability criteria for this aspect of the QA Program. During this data collection and evaluation process, a systematic bias was observed and corrections to the efficiency curve were implemented, which reduced the systematic bias and improved analytical accuracy.