The V26 containment vessel was procured by the Project Manager, Non-Stockpile Chemical Materiel (PMNSCM) for use on the Phase-2 Explosive Destruction Systems. It was fabricated under Code Case 2564 of the ASME Boiler and Pressure Vessel Code, which provides rules for the design of impulsively loaded vessels [1]. The explosive rating for the vessel, based on the Code Case, is nine (9) pounds TNT-equivalent for up to 637 detonations. This report documents the results of tests that were performed on the vessel at Sandia National Laboratories to qualify the vessel for explosive use [2]. Three of these explosive tests consisted of: (1) 9lbs bare charge of Composition C-4 (equivalent to 11.25lbs TNT); (2) a 7.2lbs bare charge of Composition C-4 (equivalent to 9lbs TNT); (3) a bare charge of 9lbs cast TNT. The results of these tests are compared in order to provide an understanding of how varying charge size affects vessel response when the ratio of free volume to charge volume is small, and in making direct comparisons between TNT and Composition C-4 for TNT equivalency calculations. In a previous paper [3], the 7.2lbs bare charge of Composition C-4, (2) above, was compared to 7.2lbs of Composition C-4 distributed into 6 charges.
This report documents the results of two of tests that were performed on an explosive containment vessel at Sandia National Laboratories in Albuquerque, New Mexico in July 2013 to provide some deeper understanding of the effects of charge geometry on the vessel response [1]. The vessel was fabricated under Code Case 2564 of the ASME Boiler and Pressure Vessel Code, which provides rules for the design of impulsively loaded vessels [2]. The explosive rating for the vessel, based on the Code Case, is nine (9) pounds TNT-equivalent. One explosive test consisted of a single, centrally located, 7.2 pound bare charge of Composition C-4 (equivalent to 9 pounds TNT). The other test used six each 1.2 pound charges of Composition C-4 (7.2 pounds total) distributed in two bays of three.
The objective of the test was to qualify the vessel for its intended use by subjecting it to a 1.25 times overtest. The criteria for success are that the measured strains do not exceed the calculated strains from the vessel analysis, there is no significant additional plastic strain on subsequent tests at the rated design load (shakedown), and there is no significant damage to the vessel and attached hardware that affect form, fit, or function. Testing of the V25 Vessel in 2011 established a precedent for testing V26 [2]. As with V25, two tests were performed to satisfy this objective. The first test used 9 pounds of Composition C-4 (11.25 lbs. TNT-equivalent), which is 125 percent of the design basis load. The second test used 7.2 pounds of Composition C-4 (9 lbs. TNT-equivalent) which is 100 percent of the design basis load. The first test provided the required overtest while the second test served to demonstrate shakedown and the absence of additional plastic deformation. Unlike the V25 vessel, which was mounted in a shipping cradle during testing, the V26 vessel was mounted on the EDS P2U3 trailer prior to testing. Visual inspections of the EDS vessel, surroundings, and diagnostics were completed before and after each test event. This visual inspection included analyzing the seals, fittings, and interior surfaces of the EDS vessel and documenting any abnormalities or damages. Photographs were used to visually document vessel conditions and findings before and after each test event.
Establishing design and inspection criteria for impulsively loaded vessels requires a precise understanding of the damage mechanisms and failure modes experienced by the vessels. To that end, Stress Engineering Services, Inc. performed a metallurgical examination of three impulsively loaded vessels that Sandia National Laboratories had intentionally tested to failure, two by impulsive loading and one by hydrotest after impulsive load testing. The vessels were scale models of Type 316 stainless steel vessels use for disposal of chemical ordnance. The examination identified microstructural effects, mechanical damage, and fractographic features associated with exposure to impulsive loads. In particular, the examination identified damage associated with wave interference patterns and unusual patterns of deformation and cracking associated with residual ferrite stringers within the austenitic matrix of the alloy. The characterization of the damage mechanisms leading to failure has direct relevance to ASME design criteria, to the selection of appropriate materials, and to inspection practices for impulsively loaded vessels.
In a multiyear research agreement with Tenix Investments Pty. Ltd., Sandia has been developing field deployable technologies for detection of biotoxins in water supply systems. The unattended water sensor or UWS employs microfluidic chip based gel electrophoresis for monitoring biological analytes in a small integrated sensor platform. This instrument collects, prepares, and analyzes water samples in an automated manner. Sample analysis is done using the {mu}ChemLab{trademark} analysis module. This report uses analysis results of two datasets collected using the UWS to estimate performance of the device. The first dataset is made up of samples containing ricin at varying concentrations and is used for assessing instrument response and detection probability. The second dataset is comprised of analyses of water samples collected at a water utility which are used to assess the false positive probability. The analyses of the two sets are used to estimate the Receiver Operating Characteristic or ROC curves for the device at one set of operational and detection algorithm parameters. For these parameters and based on a statistical estimate, the ricin probability of detection is about 0.9 at a concentration of 5 nM for a false positive probability of 1 x 10{sup -6}.