Shrapnel impact probability and diagnostic port failure analysis for LLNL`s explosives testing contained firing facility (CFF)
Lawrence Livermore National Laboratory` s (LLNL) Contained Firing Facility (CFF) is a facility to be constructed for explosives testing of up to 60 kg of explosives at LLNL` s Site 300 Explosives Test Site. The CFF will be a large, rectangular, reinforced concrete firing chamber, lined with steel for shrapnel protection. The CFF will contain several glass ports for cameras, lasers, and other diagnostic equipment to be used for data collection during planned explosives detonations. Glass is used due to the need for the greatest possible optical clarity. This study was performed during the CFF final design stage to determine probabilities and consequences (bounding and best estimate) of impact of shrapnel, due to concerns about the possible effects of rebounding shrapnel on these glass diagnostic ports. We developed a customized version of the Persistence of Vision{trademark} Ray-Tracer (POV-Ray{trademark}) version 3.02 code for the Macintosh TM Operating System (MacOS{trademark}). POV-Ray creates three- dimensional, very high quality (photo-realistic) images with realistic reflections, shading, textures, perspective, and other effects using a rendering technique called ray-tracing. It reads a text file that describes the objects and lighting in a scene and generates an image of that scene from the viewpoint of a camera, also described in the text file. The customized code (POV-Ray Shrapnel Tracker, V3.02 - Custom Build) generates fragment trajectory paths at user designated angle intervals in three dimensions, tracks these trajectory paths through any complex three-dimensional space, and outputs detailed data for each ray as requested by the user, including trajectory source location, initial direction of each trajectory, vector data for each surface/trajectory interaction, and any impacts with designated model target surfaces during any trajectory segment (direct path or reflected paths). This allows determination of the three-dimensional trajectory of each simulated particle, as well as overall and individual fragment probabilities of impact with any designated target(s) in the three-dimensional model. It also allows identification of any areas of particular concern due to grouping (in discrete areas) of fragment paths that lead to hits on the target areas of concern. The default code output includes data for specified fragment paths up through four reflections, with the number of target hits for each path segment listed. Output is grouped by target number, arbitrarily assigned in order as the target objects are declared in the input model text file. Hits on the targets are listed by path segments (e.g., direct path, one bounce, two bounces, etc.). The code has the capability to output a separate data file containing full x, y, and z directional data for each fragment path, to output just the data for a user specified number of reflections, or to output data for just the paths that lead to hits on the specified targets. The code assumes that the shrapnel originates from a point source located at the defined camera position in the model. The shrapnel pieces are assumed to be ideal, spherical, point-sized objects. Travel paths are assumed to be short and at high speed, i.e., gravitational curvature of the shrapnel paths is ignored. Reflections are assumed to be ideal, i.e., the reflection angle is equal to the incident angle. Both irregular fragment shapes and rotational momentum of the fragments would be expected to cause individual fragments to deviate from the ideal fragment paths. However, the aggregate real-world fragment paths would not be expected to significantly deviate from the ideal paths because of the averaging out of the deviations. Any collisions or other interactions between fragments are ignored. The analysis code has the capability to simulate non-ideal reflections caused by irregular fragment shapes by introducing either regular or random surface roughness or bumpiness. However, no simulation method available in the analysis code has been identified to simulate the effects of rotational energy.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 302861
- Report Number(s):
- UCRL-JC-129396; CONF-980616-; ON: DE98058618; BR: YN0100000
- Resource Relation:
- Conference: Conference on integrating safety analysis into safety management, Park City, UT (United States), 15-19 Jun 1998; Other Information: PBD: 22 May 1998
- Country of Publication:
- United States
- Language:
- English
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