Browsing by Subject "Nonproliferation"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Bayesian network analysis of nuclear acquisitions(2009-05-15) Freeman, Corey RossNuclear weapons proliferation produces a vehement global safety and security concern. Perhaps most threatening is the scenario of a rogue nation or a terrorist organization acquiring nuclear weapons where the conventional ideas of nuclear deterrence may not apply. To combat this threat, innovative tools are needed that will help to improve understanding of the pathways an organization will take in attempting to obtain nuclear weapons and in predicting those pathways based on existing evidence. In this work, a methodology was developed for predicting these pathways. This methodology uses a Bayesian network. An organization?s motivations and key resources are evaluated to produce the prior probability distributions for various pathways. These probability distributions are updated as evidence is added. The methodology is implemented through the use of the commercially available Bayesian network software package, Netica. A few simple scenarios are considered to show that the model?s predictions agree with intuition. These scenarios are also used to explore the model?s strengths and limitations. The model provides a means to measure the relative threat that an organization poses to nuclear proliferation and can identify potential pathways that an organization will likely pursue. Thus, the model can serve to facilitate preventative efforts in nuclear proliferation. The model shows that an organization?s motivations biased the various pathways more than their resources; however, resources had a greater impact on an organization?s overall chance of success. Limitations of this model are that (1) it can not account for deception, (2) it can not account for parallel weapon programs, and (3) the accuracy of the output can only be as good as the user input. This work developed the first, published, quantitative methodology for predicting nuclear proliferation with consideration for how an organization?s motivations impact their pathway probabilities.Item A game theoretic approach to nuclear safeguards selection and optimization(2013-08) Ward, Rebecca Morgan; Schneider, Erich A.This work presents a computational tool that calculates optimally efficient safeguarding strategies at and across nuclear fuel cycle facilities for a cost-constrained inspector seeking to detect a state-facilitated diversion or misuse. The tool employs a novel methodology coupling a game theoretic solver with a probabilistic simulation model of a gas centrifuge enrichment plant and an aqueous reprocessing facility. The simulation model features a suite of defender options at both facilities, based on current IAEA practices, and an analogous menu of attacker proliferation pathway options. The simulation model informs the game theoretic solver by calculating the detection probability for a given inspector-proliferator strategy pair and weighting the detection probability by the quantity and quality of material obtained to generate a scenario payoff. Using a modified fictitious play algorithm, the game iteratively calls the simulation model until the equilibrium is reached and outputs the optimal inspection strategy, proliferation strategy, and the equilibrium scenario payoff. Two types of attackers are modeled: a breakout-willing attacker, whose behavior is driven by desire for high value material; and a risk-averse attacker, who desires high-value material but will not pursue a breakout strategy that leads to certain detection. Results are presented demonstrating the sensitivity of defender strategy to budget and attacker characteristics, for an attacker known to be targeting the enrichment or reprocessing facility alone, as well as an attacker who might target either facility. The model results indicate that the optimal defender resource allocation strategy across multiple facilities hardens both facilities equitably, such that both facilities are equally unattractive targets to the attacker.Item A generalized method for rapid analysis of active interrogation systems for detection of special nuclear material(2013-08) Armstrong, Hirotatsu; Schneider, Erich A.Detection of special nuclear material (SNM) being smuggled into the US through ports of entry has been identified as a crucial capability for ensuring the safety and security of the US from radiological threats. Programs such as the NNSA's Second Line of Defense aim to deploy detection systems, both domestically and abroad, in an attempt to interdict the SNM before it reaches its destination. Active interrogation (AI) is a technique that relies on the detection of emitted particles which are produced when SNM is bombarded with a source of high energy photons or neutrons. This work presents a general framework that allows for fast radiation transport modeling of AI scenarios by generating families of response functions which depict neutron, gamma, or electron radiation exiting various regions within the problem, per unit source of radiation entering the region. The solution for a given scenario, typically the detector count rate, is computed by injecting a source term into the first region and applying the appropriate response functions, in sequence, for each subsequent region. For the AI systems modeled in this work, the source is an electron beam in a linear accelerator. Subsequent response functions create and transport bremsstrahlung photons into the SNM, and transport neutrons born in the problem to a detector. The computed solution is comparable to that of a full Monte Carlo simulation, but is assembled in orders of magnitude less time from pre-computed response function libraries. The ability to rapidly compute detector spectra for complicated AI scenarios opens up research and analysis possibilities not previously possible, including conducting parametric studies of scenarios spanning a large portion of the threat space and generating detector spectra used for conditioning and testing of alarm algorithms.Item Quantitative NDA Measurements of Advanced Reprocessing Product Materials Containing U, NP, PU, and AM(2013-04-05) Goddard, BradenThe ability of inspection agencies and facility operators to measure powders containing several actinides is increasingly necessary as new reprocessing techniques and fuel forms are being developed. These powders are difficult to measure with nondestructive assay (NDA) techniques because neutrons emitted from induced and spontaneous fission of different nuclides are very similar. A neutron multiplicity technique based on first principle methods was developed to measure these powders by exploiting isotope-specific nuclear properties, such as the energy-dependent fission cross sections and the neutron induced fission neutron multiplicity. This technique was tested through extensive simulations using the Monte Carlo N-Particle eXtended (MCNPX) code and by one measurement campaign using the Active Well Coincidence Counter (AWCC) and two measurement campaigns using the Epithermal Neutron Multiplicity Counter (ENMC) with various (?,n) sources and actinide materials. Four potential applications of this first principle technique have been identified: (1) quantitative measurement of uranium, neptunium, plutonium, and americium materials; (2) quantitative measurement of mixed oxide (MOX) materials; (3) quantitative measurement of uranium materials; and (4) weapons verification in arms control agreements. This technique still has several challenges which need to be overcome, the largest of these being the challenge of having high-precision active and passive measurements to produce results with acceptably small uncertainties.Item Secure or seclude : U.S. nuclear policy and nuclear states, a comparison of India and Pakistan(2010-05) Chaney, Brent Buie; Gavin, Francis J.; Chesney, RobertThe U.S. has implemented a two-track nuclear policy since the Cold War. The first track is non-proliferation and the second track involves securing all nuclear materials. The two-track nuclear policy has been effective, but at times non-proliferation efforts are contradicted by the US supporting nuclear programs by securing nuclear materials. The current greatest threat to nuclear security is the acquisition of nuclear materials by an extremist or terrorist organization. Can the US combat the current growing threat of loose nukes with the two-track policy?