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Title: Thermal safety characterization on PETN, PBX-9407, LX-10-2, LX-17-1 and detonator in the LLNL's P-ODTX system

Abstract

Incidents caused by fire and other thermal events can heat energetic materials that may lead to thermal explosion and result in structural damage and casualty. Thus, it is important to understand the response of energetic materials to thermal insults. The One-Dimensional-Time to Explosion (ODTX) system at the Lawrence Livermore National Laboratory (LLNL) has been used for decades to characterize thermal safety of energetic materials. In this study, an integration of a pressure monitoring element has been added into the ODTX system (P-ODTX) to perform thermal explosion (cook-off) experiments (thermal runaway) on PETN powder, PBX-9407, LX-10-2, LX-17-1, and detonator samples (cup tests). The P-ODTX testing generates useful data (thermal explosion temperature, thermal explosion time, and gas pressures) to assist with the thermal safety assessment of relevant energetic materials and components. This report summarizes the results of P-ODTX experiments that were performed from May 2015 to July 2017. Recent upgrades to the data acquisition system allows for rapid pressure monitoring in microsecond intervals during thermal explosion. These pressure data are also included in the report.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1396199
Report Number(s):
LLNL-TR-739143
DOE Contract Number:
AC52-07NA27344
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY

Citation Formats

Hsu, P. C., Strout, S., Reynolds, J. G., Kahl, E., Ellsworth, F., and Healy, T.. Thermal safety characterization on PETN, PBX-9407, LX-10-2, LX-17-1 and detonator in the LLNL's P-ODTX system. United States: N. p., 2017. Web. doi:10.2172/1396199.
Hsu, P. C., Strout, S., Reynolds, J. G., Kahl, E., Ellsworth, F., & Healy, T.. Thermal safety characterization on PETN, PBX-9407, LX-10-2, LX-17-1 and detonator in the LLNL's P-ODTX system. United States. doi:10.2172/1396199.
Hsu, P. C., Strout, S., Reynolds, J. G., Kahl, E., Ellsworth, F., and Healy, T.. 2017. "Thermal safety characterization on PETN, PBX-9407, LX-10-2, LX-17-1 and detonator in the LLNL's P-ODTX system". United States. doi:10.2172/1396199. https://www.osti.gov/servlets/purl/1396199.
@article{osti_1396199,
title = {Thermal safety characterization on PETN, PBX-9407, LX-10-2, LX-17-1 and detonator in the LLNL's P-ODTX system},
author = {Hsu, P. C. and Strout, S. and Reynolds, J. G. and Kahl, E. and Ellsworth, F. and Healy, T.},
abstractNote = {Incidents caused by fire and other thermal events can heat energetic materials that may lead to thermal explosion and result in structural damage and casualty. Thus, it is important to understand the response of energetic materials to thermal insults. The One-Dimensional-Time to Explosion (ODTX) system at the Lawrence Livermore National Laboratory (LLNL) has been used for decades to characterize thermal safety of energetic materials. In this study, an integration of a pressure monitoring element has been added into the ODTX system (P-ODTX) to perform thermal explosion (cook-off) experiments (thermal runaway) on PETN powder, PBX-9407, LX-10-2, LX-17-1, and detonator samples (cup tests). The P-ODTX testing generates useful data (thermal explosion temperature, thermal explosion time, and gas pressures) to assist with the thermal safety assessment of relevant energetic materials and components. This report summarizes the results of P-ODTX experiments that were performed from May 2015 to July 2017. Recent upgrades to the data acquisition system allows for rapid pressure monitoring in microsecond intervals during thermal explosion. These pressure data are also included in the report.},
doi = {10.2172/1396199},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 9
}

Technical Report:

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  • Incidents caused by fire and combat operations can heat energetic materials that may lead to thermal explosion and result in structural damage and casualty. Some explosives may thermally explode at fairly low temperatures (< 100 C) and the violence from thermal explosion may cause a significant damage. Thus it is important to understand the response of energetic materials to thermal insults. The One Dimensional Time to Explosion (ODTX) system at the Lawrence Livermore National Laboratory has been used for decades to measure times to thermal explosion, threshold thermal explosion temperature, and determine the kinetic parameters of thermal decomposition of energeticmore » materials. Samples of different configurations (pressed part, powder, paste, and liquid) can be tested in the system. The ODTX testing can also provide useful data for assessing the thermal explosion violence of energetic materials. This report summarizes the results of our recent ODTX experiments on PETN powder, PBX-9407 pressed part, LX-10 pressed part, LX-17 pressed part and compares the test data that were obtained decades ago with the older version of ODTX system. Test results show the thermal sensitivity of various materials tested in the following order: PETN> PBX-9407 > LX-10 > LX-17.« less
  • Cross-comparison of the results of two computer codes for the same problem provides a mutual validation of their computational methods. This cross-validation exercise was performed for LLNL's ALE3D code and AKTS's Thermal Safety code, using the thermal ignition of HMX in two standard LLNL cookoff experiments: the One-Dimensional Time to Explosion (ODTX) test and the Scaled Thermal Explosion (STEX) test. The chemical kinetics model used in both codes was the extended Prout-Tompkins model, a relatively new addition to ALE3D. This model was applied using ALE3D's new pseudospecies feature. In addition, an advanced isoconversional kinetic approach was used in the AKTSmore » code. The mathematical constants in the Prout-Tompkins code were calibrated using DSC data from hermetically sealed vessels and the LLNL optimization code Kinetics05. The isoconversional kinetic parameters were optimized using the AKTS Thermokinetics code. We found that the Prout-Tompkins model calculations agree fairly well between the two codes, and the isoconversional kinetic model gives very similar results as the Prout-Tompkins model. We also found that an autocatalytic approach in the beta-delta phase transition model does affect the times to explosion for some conditions, especially STEX-like simulations at ramp rates above 100 C/hr, and further exploration of that effect is warranted.« less
  • This study was performed to explore and assess the worst-case response of a W89-type weapons system, damaged so as to expose detonator and/or detonator safing strong link (DSSL) cables to the most extreme, credible lightning-discharge, environment. The test program used extremely high-current-level, fast-rise-time (1- to 2-{mu}s) discharges to simulate lightning strikes to either the exposed detonator or DSSL cables. Discharges with peak currents above 700 kA were required to explode test sections of detonator cable and launch a flyer fast enough potentially to detonate weapon high explosive (HE). Detonator-safing-strong-link (DSSL) cables were exploded in direct contact with hot LX-17 andmore » Ultrafine TATB (UFTATB). At maximum charging voltage, the discharge system associated with the HE firing chamber exploded the cables at more than 600-kA peak current; however, neither LX-17 nor UFTATB detonated at 250{degree}C. Tests showed that intense surface arc discharges of more than 700 kA/cm in width across the surface of hot UFTATB [generally the more sensitive of the two insensitive high explosives (IHE)] could not initiate this hot IHE. As an extension to this study, we applied the same technique to test sections of the much-narrower but thicker-cover-layer W87 detonator cable. These tests were performed at the same initial stored electrical energy as that used for the W89 study. Because of the narrower cable conductor in the W87 cables, discharges greater than 550-kA peak current were sufficient to explode the cable and launch a fast flyer. In summary, we found that lightning strikes to exposed DSSL cables cannot directly detonate LX-17 or UFTATB even at high temperatures, and they pose no HE safety threat.« less
  • Spectra of the visible emission from detonating PETN and PBX 9407 have been obtained and clearly show CN (B/sup 2/..sigma../sup +/)), CH(A/sup 2/..delta..), C/sub 2/ (d/sup 3//PI//sub g/) and NO/sub 2/(A/sup 2/B/sub 2/) as emitting species. Relative vibrational level populations in CN(B) and C/sub 2/(d) were measured from the intensity of their well-resolved vibronic bands in the PETN detonations. These results were used to calculate Boltzmann vibrational temperatures of 3300 +- 300 K and 4100 +- 800 K for CN(B) and C/sub 2/(d), respectively. These may be lower limits to the actual detonation temperature.