Operability thresholds for thermally damaged EBW detonators

Journal Article · Sun Jan 02 23:00:00 EST 2022 · Combustion and Flame

DOI:https://doi.org/10.1016/j.combustflame.2021.111953· OSTI ID:1841979

Hobbs, Michael L. ^[1]; Kaneshige, Michael J. ^[1]; Coronel, Stephanie A. ^[1]

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1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Operability thresholds that differentiate between functional RP-87 exploding bridge wire (EBW) detonators and nonfunctional RP-87 EBW detonators (duds) were determined by measuring the time delay between initiation and early wall movement (function time). The detonators were inserted into an externally heated hollow cylinder of aluminum and fired with current flow from a charged capacitor using an exploding bridge wire (EBW initiated). Functioning detonators responded like unheated pristine detonators when the function time was 4 μs or less. The operability thresholds of the detonators were characterized with a simple decomposition cookoff model calibrated using a modified version of the Sandia Instrumented Thermal Ignition (SITI) experiment. These thresholds are based on the calculated state of the PETN when the detonators fire. The operability threshold is proportional to the positive temperature difference (ΔT) between the maximum temperature within the PETN and the onset of decomposition (~406 K). Furthermore, the temperature difference alone was not sufficient to define the operability threshold. The operability threshold was also proportional to the time that the PETN had been at elevated temperatures. That is, failure was proportional to both temperature and reaction rate. The reacted gas fraction is used in the current work for the reaction correlation. Melting of PETN also had a significant effect on the operability threshold. Detonator failure occurred when the maximum temperature exceeded the nominal melting point of PETN (414 K) for 45±5 s or more.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: NA0003525
• OSTI ID: 1841979
• Alternate ID(s): OSTI ID: 1862422
• Report Number(s): SAND--2022-0108J; 702381
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Vol. 238; ISSN 0010-2180
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
Cookoff
Detonators
PETN
Thermal damage