Section 2 POPOVER Review Panel Report The POPOVER Review Panel The purpose of the POPOVER test series was to measure and collect data from experiments designed to verify the integrity of the Big Explosive Experiment Facility (BEEF). The ultimate goal of these tests was to gain absolute confidence in the integrity of BEEF'S structures and equipment and to allow personnel to operate in that facility's Bunker B4-300 during future experiments. To amin this goal, an independent assessment of the POPOVER test series was carried out by assembling a group of mechanical, civil, and instrumentation engineers and experts in explosives safetythe POPOVER Review Panel. The Review Panel members and their areas of expertise were: C. F. (Joe) Baker (civil and blast effects) Bart W. Costerus (instrumentation) Anthony M. Davito, chairman (structural) Paul J. Grace (explosives safety) Chi Yung (John) King (structural and blast effects) Thomas A. Nelson (structural mechanics) John W. Pastrnak (mechanical and blast effects) David W. Prokosch (explosives safety) This report documents the evaluation of BEEF by the POPOVER Review Panel. POPOVER Review Panel Report The site shall be capable of multiple reuse with a low probability of damage to diagnostic equipment and without injury to test personnel when thousands of pounds of conventional HE per experiment are detonated. BEEF Site and Bunker Description BEEF is located in Area 4 at NTS. Two bunkers, B4-300 and B4-480, at the BEEF site were selected for the project because they met the B-Division criteria and because calculations showed that they would withstand pressures and shocks from explosive activities with minimum modifications. Figure 3-1 shows a plan view and cross section of the layout of Bunkers B4-300 and B4-480. After verification, Bunker B4-300 will contain the personnel-occupied control room and laser sources. The BEEF bunkers will be fitted with a portable fire extinguisher system and smoke detectors. Bunker B4-480 will serve as a camera room containing five stations for high-speed fhming cameras and imageconverter cameras with optical ports to the f h g table. A Febetron housing is located 33 ft (10 m) from, and directly in line with, the large test shots. Figure 3-2 shows the configuration of the Febetron housing before an earth berm (located just in front of the housing) was constructed. OSHA Requirement In addition to the above requirements, the Occupational Safety and Health Administration (OSHA) has set an exposure limit to impulsive or impact noise of 140 dB peak C-weighted sound pressure, regardless of the impulse frequency or pulse duration.6 In the case of BEEF, personnel exposures to impulsive noise caused by the explosives detonation will most likely be the controlling factor.

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Researchers at Lawrence Livermore National Laboratory are developing a high performance filament wound composite firing vessel intended for containment of one time detonation of explosive assemblies that contain toxic metals and gaseous by-products. A 2-meter diameter pressure vessel is being designed for containment of up to 80 lb tnt equivalent explosive without leakage. Due to the complexity of assuring good o-ring sealing ability for explosive generated dynamic pressures in excess of 40,000 psig (280 MPa), multiple seals in-series are used at the vessel openings. To assess and monitor the integrity of these seals during actual detonations within the vessel; miniature pressure and gas sample measurements were made upon the interstitial volume between the o-ring seals. Recent results of this prototype monitoring system indicated that at least two of the seven o-ring seals were required to adequately prevent transient leakage of toxic particulates from test series CVD-2a as evidenced by mass spectrograph quantities of 10% argon vessel pre-charge as a fiducial indicator gas and later confirmed by particulate swipes for metals.

A worldwide trend for explosives testing has been to replace open-air detonations with containment vessels, especially when any hazardous materials are involved. As part of the National Nuclear Security Administration's (NNSA) effort to ensure the safety and reliability of the nation's nuclear stockpile, researchers at Lawrence Livermore National Laboratory have been developing a high performance filament wound composite firing vessel that is nearly radiographically transparent. It was intended to contain a limited number of detonations of metal cased explosive assemblies in radiographic facilities such as the Advanced Hydrodynamic Facility (AHF) being studied by Los Alamos National Laboratory. A 2-meter diameter pressure vessel was designed to contain up to 35 kg (80 lb) of TNT equivalent explosive without leakage. Over the past 5 years a total of three half-scale (1 meter diameter) vessels have been constructed, and two of them were tested to 150% load with 8.2 kg (18-pound) spheres of C4 explosive. The low density and high specific strength advantages used in this composite vessel design may have other additional applications such as transporting sensitive explosives that could otherwise be moved only in very small quantities. Also, it could be used for highly portable, explosive containment systems for law enforcement.

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...