PETN ignition experiments and models.

Ignition experiments from various sources, including our own laboratory, have been used to develop a simple ignition model for pentaerythritol tetranitrate (PETN). The experiments consist of differential thermal analysis, thermogravimetric analysis, differential scanning calorimetry, beaker tests, one-dimensional time to explosion tests, Sandia's instrumented thermal ignition tests (SITI), and thermal ignition of nonelectrical detonators. The model developed using this data consists of a one-step, first-order, pressure-independent mechanism used to predict pressure, temperature, and time to ignition for various configurations. The model was used to assess the state of the degraded PETN at the onset of ignition. We propose that cookoff violence for PETN can be correlated with the extent of reaction at the onset of ignition. This hypothesis was tested by evaluating metal deformation produced from detonators encased in copper as well as comparing postignition photos of the SITI experiments.

Realistic radiological dispersal device hazard boundaries and ramifications for early consequence management decisions.

If dispersal occurs from an explosive radiological dispersal device, first responders need to know what actions they need to take to protect life and property. Many of the decisions required to minimize exposure will be made during the first hour. To help the first responder decide what countermeasures to employ, Sandia National Laboratories has established realistic hazard boundaries for acute and sub-acute effects relevant to radiological dispersal devices. These boundaries were derived from dispersal calculations based on the aerosolization behavior of devices tested in the Sandia Aerosolization Program. For 20 years, the Sandia Aerosolization Program has performed explosive and non-explosive aerosolization tests relevant to radiological dispersal devices. This paper discusses (1) the method and technical bases used to establish hazard boundaries and the appropriate actions that apply within those areas and (2) whether large-scale evacuations or sheltering in place are appropriate responses to a radiological dispersal device event.