Year
2003
Abstract
The inventory data validation and assessment process is the basis for confidence in the accuracy and reliability of the Department's nuclear materials inventory data. This process is the essence of the inventory data quality and accuracy assurance function of the Office of Plutonium, Uranium, and Special Materials Inventory (SO-62). These assessments provide a basis for complex-level conclusions on the quality of inventory information. This work is unique as these assessments are not routinely included in field survey and Headquarters audit activities. Some of the focus areas to be addressed as part of this ongoing process include analysis of (1) cumulative inventory differences, (2) common practices among DOE/NNSA facilities concerning the use of inventory explanation codes, (3) unresolved shipper receiver differences, and (4) receipts accepted at shipper's values. These analyses will be conducted by SO-62 periodically and assessed from a complex wide perspective. The general approach is to look for trends over time, identify potential anomalies in the DOE orders or facility practices, and provide recommendations to improve the validity of data in the national data base. The efficiency and cost of data collection are also factors presently under consideration by SO-62. As an example of the types of studies that are underway as part of this process, several case studies related to data validation have recently been completed. Two of these are reported here. One study compared the practice of using \"book\" versus physical inventory to compute inventory differences (IDs) as reported quarterly to the Nuclear Materials Management and Safeguards System (NMMSS) for a specific facility. Inventory differences maintained by a facility may differ from those retained in the NMMSS for a variety of reasons. For example, physical inventory schedules may not be in sync with NMMSS reporting requirements. When physical inventories are conducted bi-monthly and NMMSS requires ID information to be reported quarterly, discrepancies between the two data bases can occur. In this scenario, it is never possible to report an ID based solely on physical inventories to NMMSS, as one endpoint of the reporting period always lies within two physical inventories. The results of this case study indicate that (1) NMMSS accurately reflects the inventory difference data for the period investigated, and (2) use of the \"book\" value does not introduce a significant bias when ID's are accumulated over a long enough period of time. However, analysis of quarterly \"book\" ID's at the NMMSS level is of little use without additional site-specific data because of the inability to localize anomalies. A second case study examined the usage of ID reporting codes and found thatinterpretations of the existing orders varied across the complex. These studies require the compilation of data from the NMMSS, its analysis, and detailed discussions with the field. These case studies have led to an improved understanding by SO-62 of the conditions in the field, the problems facilities and field offices face, and a better understanding of the way the existing orders are being interpreted. Further studies are required and are now being planned.