Year
2006
Abstract
Development of accurate and reliable methods to safeguard spent nuclear fuel residing in dry interim storage facilities is of key interest to safeguards organizations. As storage pools in many countries reach their design capacity, the number of fuel assemblies transferred from pools to dry storage is rapidly increasing worldwide. Measurements of gross neutron and gamma ray signals using the Fork detector are used routinely and widely in safeguards inspections. However, capacity to analyze and evaluate spent fuel measurement data is not very far developed. Because of the complex behavior of changes in the radiation emission signatures from different fuel types, enrichments, duration of irradiation, and decay time, several safeguards organizations are investigating increased use of modern computational methods to support the evaluation and interpretation of Fork detector results to improve the ability to verify the declared characteristics of irradiated nuclear material, and re-verify the completeness of the inventory in the future. Because these burnup codes typically track a wide range of isotopic concentrations and activities, they are also being pursued by the IAEA as a potential tool to support the analysis of environmental samples obtained from nuclear facilities worldwide. In this paper we present methods and data library development activities and several applications supporting spent fuel safeguards.