Year
2008
Abstract
The recycling of spent nuclear fuel (SNF) is a task that the United States must consider to alleviate the burden on our nation’s long-term radioactive waste storage facilities. Currently, the US does not have a large-scale SNF recycling facility, and therefore lacks the practical knowledge and experience of performing tasks associated with SNF recycling. Recently, the Oak Ridge National Laboratory (ORNL) started a complete, small-scale SNF recycling program under the Global Nuclear Energy Partnership known as the Coupled-End-to-End (CETE) Demonstration. The CETE Demonstration provides ORNL staff a unique opportunity to perform direct measurements of fissile content in single rods of spent fuel. Previously this type of measurement either could not be performed, or could only be performed with questionable validity of results due to the manner in which the US stores its SNF. The SNF is stored in fuel bundles underwater, which does not allow measurement of a single rod and introduces effects due to the presence of water. These two impediments to measuring SNF can be eliminated during the CETE Demonstration. This paper describes the evaluation and testing of several nondestructive assay (NDA) techniques, to quantify the amount of fissile material present during the SNF examination phase of the CETE Demonstration. Three NDA techniques have been examined: gamma-ray spectroscopy, neutron-neutron coincidence counting, and neutron-gamma coincidence counting. The data collected from these measurements will then be analyzed and compared with the results of destructive analyses performed during later phases of the CETE Demonstration. Isolating an NDA technique to quantify the fissile content of SNF could prove indispensable. It is prudent to identify the quantity of fissile material present in the SNF as soon as possible to address several critical issues including nuclear material control and accountability, and criticality safety.