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Six Degrees of Freedom (6DOF) Simulations of Supersonic Fragment Trajectories

Yeh, Peter D.

In this report a process using existing technologies at Sandia National Laboratories (SNL) to simulate the six degrees-of-freedom (6DOF) trajectories of explosive fragments is described and tested. First, aerodynamic forces and moments as functions of orientation are computed using the SIERRA/Aero supersonic flow solver. The forces and moments are normalized and tabulated in a database. Second, this the aerodynamic coefficient database is imported into a 6DOF rigid body dynamics solver in order to compute the resulting trajectories. The supersonic flow simulations are tested for simple geometries and show good agreement with literature values. The simulation procedure is then demonstrated for an example fragment. The results of the example fragment indicate that the distance traveled in the early ight (from 2.5 km/s until decreasing down to 1 km/s) varies widely depending on the initial orientations. The fragment trajectory distribution and steady tumbling rate is explored. The study indicates that a 6DOF analysis will yield information about a spread of possible trajectories, while using an average drag coefficient can only represent the most likely trajectory.

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TYPE SAND Report YEAR 2019
DOIOSTI

Light Water Reactor Sustainability Program: September 2019 Physical Security Stakeholder Working Group Meeting

Osborn, Douglas; Lord, Jodie; Werner, Hannah J.

The LWRS Program Physical Security Pathway held the first meeting of the Physical Security Stakeholder working group on September 10-12, 2019 at Sandia National Laboratories. This working group is comprised of nuclear enterprise physical security stakeholders and the meeting included over 10 Utilities representing roughly 60 nuclear power plants, two staff from the Nuclear Regulatory Commission, physical security vendors, the Nuclear Energy Institute, the Electric Power Research Institute, and staff from Sandia National Laboratories and Idaho National Laboratory. The working group was established with the objectives of providing stakeholder feedback to the LWRS Program on their research and development needs and priorities, socializing the progress of Physical Security Pathway initiatives, and identifying opportunities for additional engagement and participation of stakeholders in the pathway research activities. The working group also provided a forum for physical security professionals to share common experiences and recommend prioritized activities based on their common needs.

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TYPE SAND Report YEAR 2019
DOIOSTI

Tritium Pressure Enhancement on the TPBAR Cladding by Physical Processes at the Getter

Cowgill, Donald F.

Tritium for the U.S. nuclear weapon stockpile is produced in tritium producing burnable absorber rods (TPBARs) inserted into Tennessee Valley Authoritys (TVA) light-water nuclear reactors. The rods are stainless steel tubes with a permeation barrier coating and internal components that generate and contain the tritium. The TPBAR incorporates a Ni-plated Zircoloy getter tube to capture tritium and prevent it from reaching the rod cladding and permeating into the environment. Under the conventional view of getter behavior, the tritium pressure outside the getter tube is expected to be limited to the equilibrium vapor pressure of Zr hydride at the temperature of the rod as long as the total hydrogen concentration remains below the capacity of the hydride. Since the tritium pressure is higher within the rod core, this behavior relies on the thin getters ability to hold off a differential tritium pressure. The effective tritium pressure on the cladding can also be enhanced by isotope exchange. Hydrogen ingress through the cladding from the reactor coolant creates a hydrogen pressure on the outer surface of the getter that can exchange with tritium, allowing the tritium partial pressure to increase toward this hydrogen gettering pressure. The goal of this work was to use laboratory-scale experiments to examine these mechanisms and create a model of getter behavior that describes tritium transport within the TPBAR. A third mechanism wherein the concentration at the outer surface of the getter is increased by the temperature gradient within the getter tube wall (the Soret effect) is not experimentally tested but is captured in the model. While not conclusively demonstrated by the experiments due to low pressure, high temperature, and small gap volume conditions, the model shows that when combined, the three mechanisms can explain both the magnitude and time dependence of the tritium release observed for reactor fuel assemblies with TPBARs. The model also shows how various modifications of the TPBAR design can reduce this tritium release into the environment.

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TYPE SAND Report YEAR 2019
DOIOSTI

DEPLOYABLE COLD ATOM INTERFEROMETRY SENSOR PLATFORMS BASED ON DIFFRACTIVE OPTICS AND INTEGRATED PHOTONICS

Lee, Jongmin; Biedermann, Grant; Mcguinness, Hayden J.E.; Soh, Daniel B.S.; Christensen, Justin; Ding, Roger; Finnegan, Patrick S.; Hoth, Gregory A.; Kindel, Will; Little, Bethany J.; Rosenthal, Randy R.; Wendt, Joel R.; Lentine, Anthony L.; Eichenfield, Matt; Gehl, Michael; Kodigala, Ashok; Siddiqui, Aleem; Skogen, Erik J.; Vawter, Gregory A.; Ison, Aaron; Bossert, David; Fuerschbach, Kyle H.; Gillund, Daniel P.; Walker, Charles; De Smet, Dennis; Brashar, Connor L.; Berg, Joseph; Jhaveri, Prabodh M.; Smith, Tony G.; Kemme, Shanalyn A.; Schwindt, Peter D.

Abstract not provided.

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TYPE Conference Poster YEAR 2019
OSTI
Results 19001–19200 of 99,299
Results 19001–19200 of 99,299