Year
2007
Abstract
The New Brunswick Laboratory has been tasked by the United States Department of Energy (DOE) to administer an “inter-laboratory” control program to provide independent verification of internal quality control in nuclear materials measurements. DOE facilities performing material control and accountability measurements for nuclear material safeguards participate in the program. This program is open to international laboratories also. The program provides periodic evaluations of results from quantitative measurements of uranium and plutonium bearing materials. Both destructive and non-destructive measurement results are evaluated. One major criterion used in this evaluation is a comparison of measurement bias and precision against the respective international target values (ITVs). Large deviations from ITVs are a matter of concern as they indicate the difficulty and/or inability to detect material loss should they occur in processing, or by theft or by diversion of material. NBL maintains a permanent record of the measurement evaluation results and reports. These archives are ideal sources for analyzing long term trends in analytical performance and also an aid in setting the international target values. In the inter-laboratory program (also known as the measurement evaluation program), the test samples measurement results are evaluated against the respective characterized values using a database application program internally developed several years ago. This is being replaced by a new database program with certain enhancements and conforming to quality assurance requirements. The new program is a web-based system utilizing Java whose interface is platform independent. Data is stored in an SQL database server providing reliable retrieval, backup and restoration of data, and with multiple layers of security. The system stores data on assay and isotopic abundance measurements, performs outlier tests, compares the measurement results against the respective characterized values, calculates bias and precision of the measurements using statistical methods, and prepares evaluation reports and graphs. The new system when it becomes fully operational will require direct input of measurement results by the participants and will also permit direct electronic retrieval of reports. The main features of the new database program will be presented.