Empirical validation of the conceptual design of the LLNL 60-kg contained-firing facility

Abstract

This is an informal report intended primarily for internal or limited DISCLAIMERThis document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes.This report has been reproduced directly from the best available copy. AbstractIn anticipation of increasingly stringent environmental regulations, Lawrence Evermore National Laboratory (LLNL) is proposing to modify an existing facility to add a 60-kg firing chamber and related support areas. This modification will provide blast-effects containment for most of its open-air, highexplosive, firing operations. Even though these operations are within current environmental l i m i t s , containment of the blast effects and hazardous debris will further drastically reduce emissions to the environment and minimize the hazardous waste generated.of its long-term ability to contain all blast effects from repeated internal detonations of high explosives.Another concern is how much other portions of the facility outside the firing chamber must be hardened to ensure personnel protection in the event of an accidental detonation while the chamber door is open.To assess these concerns, a 1/4-scale replica model of the planned contained firing chamber was engineered, constructed, and tested with scaled explosive charges ranging from 25 to 125% of the operational explosives limit of 60 kg. From 16 detonations of high explosives, 880 resulting strains, blast pressures, and temperatures within the model were measured to provide information for the final design.The major design consideration of such a chamber is its overall structural dynamic response in terms Executive SummaryBased on measurements obtained from scaled detonation experiments within a 1/4scale replica model, factors of safety for dynamic yield of the fixing chamber structure were calculated and compared to the design criterion of totally elastic response. The rectangular, reinforced-concrete chamber model exhibited a lightly damped vibrational response that placed the structure in alternating cycles of tension and compression. During compression, both the reinforcing steel and the concrete remained elastic. During tension, the rei...