28 research outputs found

    Analysis of International Commodity Shipping Data and the Shipment of NORM to the United States

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    As part of the Spreader Bar Radiation Detector project, PNNL analyzed US import data shipped through US ports collected over the 12 months of 2006 (over 4.5 million containers). Using these data, we extracted a variety of distributions that are of interest to modelers and developers of active and passive detection systems used to 'scan' IMCCs for potential contraband. This report expands on some of the analysis presented in an earlier report from LLNL, by investigation the foreign port distribution of commodities shipped to the US. The majority of containers shipped to the United States are 40 ft containers ({approx}70%); about 25% are 20 ft; and about 3.6% are 45 ft containers. A small fraction (<1%) of containers are of other more specialized sizes, and very few ports actually ship these unique size containers (a full distribution for all foreign ports is shown in Appendix A below). The primary foreign ports that ship the largest fraction of each container are shown in the table below. Given that 45 ft containers comprise 1 of out every 27 containers shipped to the US, and given the foreign ports from which they are shipped, they should not be ignored in screening; further testing and analysis of radiation measurements for national security with this size container is warranted. While a large amount of NORM is shipped in IMCCs, only a few specific commodities are shipped with enough frequency to present potential issues in screening IMCCs at ports. The majority of containers with NORM will contain fertilizers (5,700 containers), granite (59,000 containers), or ceramic (225,000 containers) materials. Fertilizers were generally shipping in either 20- or 40 ft containers with equal frequency. While granite is mostly shipped in 20 ft containers, ceramic materials can be shipped in either 20- or 40 ft containers. The size of container depended on the specific use of the ceramic or porcelain material. General construction ceramics (such as floor and roofing tiles) tend to be shipped in 20 ft containers. Consumer products made from ceramic materials (e.g., tableware, sinks, and toilets) are generally shipped in 40 ft containers. This distinct discrepancy is due in large part to the packaging of the commodity. Consumer products are generally shipped packed in a box loaded with Styrofoam or other packing material to protect the product from breakage. Construction ceramic materials are generally shipped in less packing material, many times consisting of only a cardboard or wooden box. Granite is almost always shipped in a 20 ft container, given its very high density

    Uranium Neutron Coincidence Collar Model Utilizing 3He

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    The Department of Energy Office of Nuclear Safeguards (NA-241) is supporting the project 'Coincidence Counting With Boron-Based Alternative Neutron Detection Technology' at Pacific Northwest National Laboratory (PNNL) for development of an alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a boron-lined proportional tube based alternative system in a configuration typically used for 3He-based coincidence counter applications. The specific application selected for boron-lined tube replacement in this project was one of the Uranium Neutron Coincidence Collar (UNCL) designs. This report, providing results for model development of a UNCL, is a deliverable under Task 2 of the project. The current UNCL instruments utilize 3He tubes. As the first step in developing and optimizing a boron-lined proportional counter based version of the UNCL, models of eight different 3He-based UNCL detectors currently in use were developed and evaluated. A comparison was made between the simulated results and measured efficiencies for those systems with values reported in the literature. The reported experimental measurements for efficiencies and die-away times agree to within 10%

    Algorithms Performance Investigation of a Generalized Spreader-Bar Detection System

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    A “generic” gantry-crane-mounted spreader bar detector has been simulated in the Monte-Carlo radiation transport code MCNP [1]. This model is intended to represent the largest realistically feasible number of detector crystals in a single gantry-crane model intended to sit atop an InterModal Cargo Container (IMCC). Detectors were chosen from among large commonly-available sodium iodide (NaI) crystal scintillators and spaced as evenly as is thought possible with a detector apparatus attached to a gantry crane. Several scenarios were simulated with this model, based on a single IMCC being moved between a ship’s deck or cargo hold and the dock. During measurement, the gantry crane will carry that IMCC through the air and lower it onto a receiving vehicle (e.g. a chassis or a bomb cart). The case of an IMCC being moved through the air from an unknown radiological environment to the ground is somewhat complex; for this initial study a single location was picked at which to simulate background. An HEU source based on earlier validated models was used, and placed at varying depths in a wood cargo. Many statistical realizations of these scenarios are constructed from simulations of the component spectra, simulated to have high statistics. The resultant data are analyzed with several different algorithms. The simulated data were evaluated by each algorithm, with a threshold set to a statistical-only false alarm probability of 0.001 and the resultant Minimum Detectable Amounts were generated for each Cargo depth possible within the IMCC. Using GADRAS as an anomaly detector provided the greatest detection sensitivity, and it is expected that an algorithm similar to this will be of great use to the detection of highly shielded sources

    Spreader-Bar Radiation Detection System Enhancements: A Modeling and Simulation Study

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    This report provides the modeling and simulation results of the investigation of enhanced spreader bar radiation detection systems
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