Determination of Residual Low-Order Detonation Particle Characteristics
Matthew Bigl | U.S. Army Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory
Inherent in the increased effort by the Department of Defense (DoD) to sustain military training ranges is the necessity to understand the loading of munitions constituents on those ranges. High-order detonations deposit very little explosive residues on ranges, and failure to detonate (a dud) leads to no short-term (year to decade) deposition as the explosive filler remains encased in the munition body. The majority of explosives deposited on ranges result from low-order (LO) detonations that are characterized by 0.1-25% of the munitions’ energetic filler scattered as particles on the impact area. The spatial distribution, size, mass, morphology, and composition of particles from LO detonations are crucial factors in contaminant fate and transport models and munitions Life Cycle Environmental Assessments (LCEA). The primary objective of this project is to demonstrate the methodology for LO command detonation, sampling, and laboratory processing for post-detonation LO particles. By demonstrating a validated methodology for LO detonation investigations, current and future munitions can be accurately characterized to provide critical data to fate and transport models and LCEAs.
The technology to be demonstrated under this research will consist of a method for initiating, sampling, processing, and analyzing LO detonation particles from both conventional and insensitive munitions. Prior research under ER-2219 showed that LO detonations of common artillery rounds can be initiated using a command-detonation system on ice, allowing for the entire residual energetics mass to be collected. Preliminary work on samples of these particles show that they can be isolated by freeze-drying and then studied intact. This research will demonstrate this technology on 60- and 81-mm insensitive and conventional mortar rounds and will characterize the residual LO detonation particles. Previous work characterizing these events has relied on the use of sieving in order to estimate particle size, whereas under this demonstration the research team will utilize a Laser Diffraction Particle Size Analyzer (LDPSA), newly acquired by U.S. Army Cold Regions Research and Engineering Laboratory (CRREL). LDPSA is a more precise measurement of particle size with an extremely high dynamic range (100 nm to 5 mm), crucial to the understanding of energetic compound fate and transport. Additional analyses of particle mass, morphology, composition, and spatial distribution around the point of detonation will also be made.
Cleanup of legacy contamination on ranges is estimated at over $10B, and offsite migration of these contaminants threatens range sustainment and warfighter access to realistic training. As models are being developed to track the fate and transport of contaminants on ranges and new munitions are being developed and certified, there is an immediate need for empirical data on LO characteristics of both conventional and insensitive munitions. This technology and its produced data will provide constraints on fate and transport models and LCEAs, leading to cost savings and environmental protection through improvements to site characterization and remediation efforts, environmental impact assessment, and acquisition risk avoidance.