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Expected result of firing an ICE load on Z without vacuum

Struve, Kenneth; Lemke, Raymond W.; Savage, Mark E.

In addressing the issue of the determining the hazard categorization of the Z Accelerator of doing Special Nuclear Material (SNM) experiments the question arose as to whether the machine could be fired with its central vacuum chamber open, thus providing a path for airborne release of SNM materials. In this report we summarize calculations that show that we could only expect a maximum current of 460 kA into such a load in a long-pulse mode, which will be used for the SNM experiments, and 750 kA in a short-pulse mode, which is not useful for these experiments. We also investigated the effect of the current for both cases and found that for neither case is the current high enough to either melt or vaporize these loads, with a melt threshold of 1.6 MA. Therefore, a necessary condition to melt, vaporize, or otherwise disperse SNM material is that a vacuum must exist in the Z vacuum chamber. Thus the vacuum chamber serves as a passive feature that prevents any airborne release during the shot, regardless of whatever containment may be in place.

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TYPE SAND Report YEAR 2010
DOIOSTI

An optimization study of stripline loads for isentropic compression experiments

PPC2009 - 17th IEEE International Pulsed Power Conference

Langston, William L.; Coats, Rebecca S.; Knudson, Marcus D.; Lemke, Raymond W.; Davis, Jean-Paul; Pointon, Timothy

The use of stripline, rather than coaxial, load configurations for isentropic compression experiments (ICE) on Sandia's Z accelerator has recently become commonplace. Such loads offer many advantages over previously-developed coaxial loads, but also introduce new issues. In this paper, we will describe the behavior of these stripline loads and examine some of the issues that arise through their use. ©2009 IEEE.

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TYPE Conference YEAR 2009
OSTIScopus

Lower bounds for the kinetic energy and resistance of wire array Z pinches on the Z pulsed-power accelerator

Physics of Plasmas

Waisman, Eduardo M.; Cuneo, Michael E.; Lemke, Raymond W.; Sinars, Daniel; Stygar, William A.

Approximate lower bounds for the kinetic energy and magnetic flux dissipation for tungsten wire arrays on the Z pulsed-power accelerator at Sandia National Laboratories [R. B. Spielman, Phys. Plasmas 5, 2105 (1998)] are obtained. A procedure, extending previous work determining pinch inductance as a function of time [E. M. Waisman, Phys. Plasmas 11, 2009 (2004)], is introduced and applied to electrical and x-ray energy measurements. It employs the pinch energy balance to determine lower bounds for the plasma kinetic energy just before the main pinch reaches the axis and for the magnetic flux dissipation during stagnation. From the lower bound for the dissipated flux, a lower bound for pinch resistance after x-ray peak power is estimated. The results of applying the introduced energy balance procedure to selected tungsten wire array implosions on Z are given. It is believed that this is the first time that a measure of wire array Z-pinch resistance at stagnation is obtained purely from data analysis without recourse to specific assumptions on the plasma motion. © 2008 American Institute of Physics.

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TYPE Journal Article YEAR 2008
ScopusOSTI
Results 101–125 of 167
Results 101–125 of 167