Los Alamos National Laboratory (LANL) requires assistance in the area of the design, execution, and analysis of critical and subcritical experiments. The North Carolina State University (NCSU) Department of Nuclear Engineering (NE) will perform novel research related to a subset of a wide array of projects including the design, execution, and analysis of critical and subcritical experiments.

The ultimate objective of the project is to enable identification of materials from measurements using an associated-particle imaging (API) system. The API system is composed of (1) a DT neutron generator source with a pixelated alpha detector capable of recording the time and direction of 14-MeV neutron emissions and (2) an array of fast organic scintillation detectors capable of recording the time-of-arrival, energy deposition, and incoming direction of neutrons and gammas. The time-, energy-, and direction-dependent distribution of neutrons and gammas interacting with the detector array can be analyzed to infer the composition, density, and thickness of materials interposed between the source and detectors.

In order for passive neutron imaging to provide value in nuclear security applications, we need to improve on existing systems by making them smaller and more efficient. Sandia is developing a single-volume scatter camera (SVSC), a very compact double-scatter fission-energy neutron imager for localization and characterization of SNM. Neutron imaging can be used for the detection of weak neutron sources, or to characterize the spatial distribution of plutonium or other neutron emitters, providing information that is valuable in arms control and emergency response applications about the fundamental nature of a nuclear explosive. Current neutron imaging systems are large (~2 m3) and heavy, making them difficult to deploy; and their sensitivity is limited by geometrical efficiency and an inherent requirement of distance between the source object and imager. We are therefore working toward a new compact neutron imager, the SVSC, which is easy to transport and deploy, has high efficiency, and can be placed near a threat object to increase sensitivity and spatial resolution.

Post-detonation forensic analysis of debris from a nuclear explosion currently relies on radiochemical separation. Although radiochemical separation is capable of developing a very detailed, highly accurate characterization of nuclear fallout, it is extremely time-consuming. Furthermore, characterization of short-lived fission products is made challenging or even impossible by the need to transport fallout samples from the detonation site to a radiochemistry laboratory. Analytical techniques that enable early characterization of nuclear fallout using field-deployable instruments can supplement traditional radiochemical analyses. In particular, gamma spectroscopic analysis of fallout has the potential to provide the needed early characterization in the field. Recent graduate research at the Air Force Institute of Technology (AFIT) has demonstrated limited capability to characterize pre-detonation nuclear explosive properties including fissile material and neutron spectrum [1], [2]. However, the recent AFIT research was based entirely on the analysis of gamma spectrum photopeaks (primarily using ratios of closely-spaced photopeaks), which were trended versus fissile material, neutron spectrum, and time after detonation. North Carolina State University (NCSU) proposes to conduct basic research to apply full-spectrum inverse analysis methods to the early characterization of nuclear fallout. Full-spectrum analysis methods employ detailed models of the gamma source term coupled to a detector response function to model all spectral features, including photopeaks and associated Compton continua. Inverse transport methods can be applied to estimate parameters of the gamma source term, including fissile material and neutron spectrum [3]. NCSU will develop full-spectrum inverse transport analysis methods applied to the characterization of nuclear fallout and evaluate their utility for estimating pre-detonation nuclear explosive properties.

NC State University, in partnership with University of Michigan, Purdue University, University of Illinois at Urbana Champaign, Kansas State University, Georgia Institute of Technology, NC A&T State University, Los Alamos National Lab, Oak Ridge National Lab, and Pacific Northwest National lab, proposes to establish a Consortium for Nonproliferation Enabling Capabilities (CNEC). The vision of CNEC is to be a pre-eminent research and education hub dedicated to the development of enabling technologies and technical talent for meeting the grand challenges of nuclear nonproliferation in the next decade. CNEC research activities are divided into four thrust areas: 1) Signatures and Observables (S&O); 2) Simulation, Analysis, and Modeling (SAM); 3) Multi-source Data Fusion and Analytic Techniques (DFAT); and 4) Replacements for Potentially Dangerous Industrial and Medical Radiological Sources (RDRS). The goals are: 1) Identify and directly exploit signatures and observables (S&O) associated with special nuclear material (SNM) production, storage, and movement; 2) Develop simulation, analysis, and modeling (SAM) methods to identify and characterize SNM and facilities processing SNM; 3) Apply multi-source data fusion and analytic techniques to detect nuclear proliferation activities; and 4) Develop viable replacements for potentially dangerous existing industrial and medical radiological sources. In addition to research and development activities, CNEC will implement educational activities with the goal to develop a pool of future nuclear non-proliferation and other nuclear security professionals and researchers.

North Carolina State University (NCSU) will collaborate with the other member institutions in the Consortium for Verification Technology (CVT) in two areas: - Subcritical measurements of Category I special nuclear material (SNM) at Nevada National Security Site (NNSS) - Application of new photodetector technology for radiation imaging NCSU will work with the CVT lead university, University of Michigan (UM) and Los Alamos National Laboratory (LANL) to plan and conduct subcritical experiments with Category I quantities of SNM in the Device Assembly Facility (DAF) at NNSS. NCSU will construct a prototype single-volume neutron scatter camera (SVNSC) using an organic scintillator detection medium (one suitable for neutron/gamma classification using pulse shape discrimination (PSD)) and a pair MCP photomultipliers. The data acquisition (DAQ) system will be constructed using commercially available VME-based 500 MS/s digitizers. In the first phase of development and testing, the SVNSC prototype will use low-resolution (5 mm ����� 5 mm) MCP photomultipliers (to keep the number of channels that have to be digitized small). In the second phase, the SVNSC photodetector will be upgraded to use high-resolution (1 mm ����� 1 mm) photodetectors. NCSU will also perform coupled MCNPX-PoliMi / Geant4 simulations of neutron and gamma transport and optical photon transport to model SVNSC performance and test alternative kinematic reconstruction algorithms. The coupled MCNPX-PoliMi/Geant4 models will be validated against experiments conducted with the phase I and phase II prototype SVNSCs. The validated models will be used to project how well the SVNSC would perform for SNM detection using a high-resolution, fast, large-area MCP-based photodetector like the LAPPD.

North Carolina State University (NCSU) students enrolled in the graduate course NE541: Nuclear Nonproliferation Technology and Policy will travel to Oak Ridge National Laboratory (ORNL) to tour ORNL and associated facilities and receive hands-on training in the ORNL Safeguards Lab. The NCSU NE541 course and the ORNL workshop were jointly developed by NCSU and ORNL to support the National Nuclear Security Administration������������������s (NNSA������������������s) Next-Generation Safeguards Initiative (NGSI) Human Capital Development (HCD) program. The ORNL workshop is an integral component of NE541. During the workshop, students will tour several facilities, including the Oak Ridge Graphite Reactor (ORGR), High Flux Isotope Reactor (HFIR), Radiochemical Engineering Development Center (REDC), Spallation Neutron Source (SNS), and the Canberra high-purity germanium manufacturing facility. Students will also receive hands-on training from ORNL scientists on measurement methods for characterizing special nuclear material.

In a nuclear materials processing facility, it is important to account accurately for the fissile material that enters and leaves the plant to prevent or detect theft or misuse. During normal operation, small amounts of material stick to walls or get trapped in equipment. Over years, these small material ?holdups? accumulate into significant quantities, sometimes several kilograms. Thus, accurately estimating the holdup is an important component of material accounting. The proposed approach fully couples predictive computational radiation transport models while integrating all data. Since the problem is nonlinear, a Newton-type iterative method will find the best fit of the predictive model with the measurements. At each step, the sensitivities of the detector measurements with respect to the model parameters (for example, mass of fissile material) are computed using radiation transport simulators, for both neutrons and gamma rays. The flux calculations returned by the transport simulators are converted to the detector measurements using a previously-validated detector response function (DRF). At the end of each step, the difference between the computed and measured values of the response of the detector at selected locations in the vicinity of the holdup governs the change for the next iterative step.

North Carolina State University (NCSU) Department of Nuclear Engineering (NE) will support ongoing efforts at Sandia National Laboratories (SNL) to develop a high-efficiency single-volume neutron scatter camera (SVNSC).

NE students field trip to ORNL as a part of the NCSU Graduate Course on radiation detection. The purpose of this project is to develop a new graduate level course, entitled ?Nuclear Nonproliferation and Safeguards?. The course is to teach nuclear security and safeguards from both global and technical perspectives. The students will be equipped with the state-of-the-art techniques of nuclear safeguards and security in this course. They will also develop holistic understanding of nuclear safeguards and security issues. The learning will be enhanced through class projects, web-based on-line interactions with subject matter experts, and a field trip to ORNL?s safeguards laboratory.