Year
2006
Abstract
Materials Protection, Accounting, and Control (MPAC) during the separation of used nuclear fuel has been identified as a critical technology area in the Advanced Fuel Cycle Initiative (AFCI) of the U.S. Department of Energy. AFCI technical directors have determined that future actinide recycling in the U.S. will require the establishment of a new standard of performance for MPAC employing new technologies or new applications of existing technologies to provide higher levels of assurance and precision. The early phase of this work is being conducted in the Transmutation Research Project at the University of Nevada, Las Vegas (UNLV) and the Idaho Accelerator Center at Idaho State University (IAC at ISU). Concepts being investigated at UNLV and ISU include x-ray spectroscopy, light absorption technologies, passive gamma-ray and neutron measurements including neutron multiplicity, and active methods that may include inducing fission with accelerator-generated photons or external neutron sources. Existing capabilities at UNLV and the ISU IAC provide an opportunity to investigate combined detection methods. We will describe two investigations of combined methods using the UNLV Neutron Multiplicity Detector System (NMDS). The NMDS is a modular system consisting of 64 3He detectors, electronics, and lead and polyethylene “bricks” that was designed and constructed at the V. G. Khlopin Radium Institute (KRI) in St. Petersburg, Russia. The system has since been extensively tested using natural cosmic radiation, neutron sources of various strengths, and accelerator-generated neutrons. The 3He detectors operate at ~6 microsecond resolution and collect data from each multiplicity event for a 256 microsecond duration. We have recently upgraded the data acquisition and analysis system with a pair of solid state boards and Labview(R) software, and the new configuration is currently being tested. The modularity of the system allows for its use in various configurations and with various sources, which will facilitate its use for MPAC technology development. In the projects described in this paper and presentation, we currently are studying two applications: assay of complete used fuel assemblies in conjunction with a massive lead slowing down spectrometer, and assay of TRU-containing process streams using multiple NMDS segments. We will present concepts, status, and plans.