Summary: Previous GAO reports on systems used to safeguard nuclear materials pointed out weaknesses in material accountability systems resulting from state-of-the-art limitations and the need for tighter physical security requirements. After the National Security Council determined that material unaccounted for (MUF) data could be released publicly, the Nuclear Regulatory Commission (NRC) and the Department of Energy (DOE) released separate reports in August 1977 on special nuclear material inventory differences. The data presented in these reports were different from that formally provided GAO and Congress. The agencies explained that the differences resulted primarily from their efforts to refine and expand the data originally provided. GAO determined that the differences resulted primarily from DOE efforts to adjust the original data provided GAO by deleting non-MUF items which were included in the MUF figures originally provided and separating low enriched uranium from high enriched uranium in the MUF data. Another major difference in reported MUF related to DOE Uranium Gaseous Diffusion Plant at Portsmouth, Ohio. DOE inability to separate low and high enriched uranium in the data contractors submitted demonstrates a serious past weakness in their reporting requirements. The changes in data given GAO and Congress raise questions about the reliability of the data and underscore the imprecision involved in accounting for MUF. Both agencies are trying to improve the capabilities of their material accountability systems.
