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A thermal decomposition model for PBX 9501 (95% HMX, 2.5% Estane® binder, 2.5% BDNPA/F nitro-plasticizer) was implemented by Dickson, et. al. The objective in this study is to estimate parameters associated with this kinetics model so it can be applied to carry out thermal ignition predictions for LX-07 (90% HMX, 10% Viton binder). LX-07 thermal ignition experiments have been carried out using the “Sandia Instrumented Thermal Ignition Apparatus”, SITI. The SITI design consists of solid cylinders (1” diameter × 1” height) of high explosive (HE) confined by a cylindrical aluminum case. An electric heater is wrapped around the outer surface of the case. This heater produces a temperature heating ramp on the outer surface of the case. Internal thermocouples measure the HE temperature rise from the center to locations close to the HE-aluminum interface. The energetic material is heated until thermal ignition occurs. A two–dimensional axisymmetric heat conduction finite element model is used to simulate these experiments. The HE thermal decomposition kinetics is coupled to a heat conduction model trough the definition of an energy source term. The parameters used to define the HE thermal decomposition model are optimized to obtain a good agreement with the experimental time to thermalmore » ignition and temperatures. Also, heat capacity and thermal conductivity of the LX-07 mixture were estimated using temperatures measured at the center of the HE before the solid to solid HMX phase transition occurred.« less

The 9975 Type B shipping package is used within the DOE complex for shipping special nuclear materials. This package is re-certified annually in accordance with Safety Analysis Report for Packaging (SARP) requirements. The package is also used at the Savannah River Site as part of the long-term storage configuration of special nuclear materials. As such, the packages do not undergo annual recertification during storage, with uncertainty as to how long some of the package components will meet their functional requirements in the storage environment. The packages are currently approved for up to 15 years storage, and work continues to provide a technical basis to extend that period. This report describes efforts by the Savannah River National Laboratory (SRNL) to extend the service life estimate of Viton® GLT and GLT-S fluoroelastomer O-rings used in the 9975 shipping package. O-rings of both GLT and GLT-S compositions are undergoing accelerated aging at elevated temperature, and are periodically tested for compression stress relaxation (CSR) behavior. The CSR behavior of O-rings was evaluated at temperatures from 175 to 400 °F. These collective data were used to develop predictive models for extrapolation of CSR behavior to relevant service temperatures (< 156 °F). The predictive model developedmore » from the CSR data conservatively indicates a service life of approximately 37 years for Viton GLT O-rings at the maximum effective service temperature of 156 °F. The estimated service life for Viton GLT-S O-rings is significantly longer.« less

A research and development task was undertaken to determine the permeabilities of hydrogen and dry air through different polymeric glove materials that are used to maintain the integrity of glovebox secondary containment. Fifteen different glove samples were obtained from four different manufacturers and samples cut from these gloves were tested. The gloves included baseline butyl rubber, Viton{reg_sign}, Dupont{reg_sign} Hypalon{reg_sign}, polyurethane, as well as composite gloves. The testing indicated that all of the vendor's butyl rubber gloves and the Jung Viton{reg_sign} gloves performed comparably in both gases.

An experimental project was initiated to characterize mass loss when heating different polymer glovebox glove material samples to three elevated temperatures, 90, 120, and 150 C. Samples from ten different polymeric gloves that are being considered for use in the tritium gloveboxes were tested. The intent of the study was to determine the amount of material lost. These data will be used in a subsequent study to characterize the composition of the material lost. One goal of the study was to determine which glove composition would least affect the glovebox atmosphere stripper system. Samples lost most of the mass in the initial 60 minutes of thermal exposure and as expected increasing the temperature increased the mass loss and shortened the time to achieve a steady state loss. The most mass loss was experienced by Jung butyl-Hypalon{reg_sign} at 146 C with 12.9% mass loss followed by Piercan Hypalon{reg_sign} at 144 C with 11.4 % mass loss and Jung butyl-Viton{reg_sign} at 140 C with 5.2% mass loss. The least mass loss was experienced by the Jung Viton{reg_sign} and the Piercan polyurethane. Unlike the permeation testing (1) the vendor and fabrication route influences the amount of gaseous species that is evolved. Additional testingmore » to characterize these products is recommended. Savannah River Site (SRS) has many gloveboxes deployed in the Tritium Facility. These gloveboxes are used to protect the workers and to ensure a suitable environment in which to handle tritium gas products. The gas atmosphere in the gloveboxes is purified using a stripper system. The process gas strippers collect molecules that may have hydrogen or its isotopes attached, e.g., waters of hydration, acids, etc. Recently, sulfur containing compounds were detected in the stripper system and the presence of these compounds accelerates the stripper system's aging process. This accelerated aging requires the strippers to be replaced more often which can impact the facility's schedule and operational cost. It was posited that sulfur bearing and other volatile compounds were derived from glove off-gassing. Due to the large number of gloves in the facility, small mass loss from each glove could result in a significant total mass of undesirable material entering the glovebox atmosphere and subsequently the stripper system. A thermogravimetric analysis (TGA) study was conducted to determine the amount of low temperature volatiles that may be expected to offgas from the gloves. The data were taken on relatively small samples but are normalized with respect to the sample's surface area. Additional testing is needed to determine the composition of the off-gassing species. The TGA study was conducted to ascertain the magnitude of the issue and to determine if further experimentation is warranted or necessary.« less

A task was undertaken to compare various properties of different glovebox gloves, having various compositions, for use in gloveboxes at the Savannah River Site (SRS). One aspect of this project was to determine the tensile strength (TS) of the gloves. Longitudinal tensile samples were cut from 15 different gloves and tensile tested. The stress, load, and elongation at failure were determined. All of the gloves that are approved for glovebox use and listed in the glovebox procurement specification met the tensile and elongation requirements. The Viton{reg_sign} compound gloves are not listed in the specification, but exhibited lower tensile strengths than permissible based on the Butyl rubber requirements. Piercan Polyurethane gloves were the thinnest samples and exhibited the highest tensile strength of the materials tested.

As part of the characterization of various glovebox glove material from four vendors, the permeability of gas through each type as a function of temperature was determined and a discontinuity in the permeability with temperature was revealed. A series of tests to determine the viscoelastic properties of the glove materials as a function of temperature using Dynamic Mechanical Analysis (DMA) was initiated. The glass transition temperature and the elastic and viscoelastic properties as a function of temperature up to maximum use temperature were determined for each glove material. The glass transition temperatures of the gloves were -60 C for butyl, -30 C for polyurethane, -16 C Hypalon{reg_sign}, - 16 C for Viton{reg_sign}, and -24 C for polyurethane-Hypalon{reg_sign}. The glass transition was too complex for the butyl-Hypalon{reg_sign} and butyl-Viton{reg_sign} composite gloves to be characterized by a single glass transition temperature. All of the glass transition temperatures exceed the vendor projected use temperatures.

The Savannah River Site (SRS) is currently storing plutonium materials in the K-Area Materials Storage (KAMS) facility. The materials are packaged per the DOE 3013 Standard and transported and stored in KAMS in Model 9975 shipping packages, which include double containment vessels sealed with dual O-rings made of Parker Seals compound V0835-75 (based on Viton{reg_sign} GLT). The outer O-ring of each containment vessel is credited for leaktight containment per ANSI N14.5. O-ring service life depends on many factors, including the failure criterion, environmental conditions, overall design, fabrication quality and assembly practices. A preliminary life prediction model has been developed for the V0835-75 O-rings in KAMS. The conservative model is based primarily on long-term compression stress relaxation (CSR) experiments and Arrhenius accelerated-aging methodology. For model development purposes, seal lifetime is defined as a 90% loss of measurable sealing force. Thus far, CSR experiments have only reached this target level of degradation at temperatures {ge} 300 F. At lower temperatures, relaxation values are more tolerable. Using time-temperature superposition principles, the conservative model predicts a service life of approximately 20-25 years at a constant seal temperature of 175 F. This represents a maximum payload package at a constant ambient temperature of 104 F,more » the highest recorded in KAMS to date. This is considered a highly conservative value as such ambient temperatures are only reached on occasion and for short durations. The presence of fiberboard in the package minimizes the impact of such temperature swings, with many hours to several days required for seal temperatures to respond proportionately. At 85 F ambient, a more realistic but still conservative value, bounding seal temperatures are reduced to {approx}158 F, with an estimated seal lifetime of {approx}35-45 years. The actual service life for O-rings in a maximum wattage package likely lies higher than the estimates due to the conservative assumptions used for the model. For lower heat loads at similar ambient temperatures, seal lifetime is further increased. The preliminary model is based on several assumptions that require validation with additional experiments and longer exposures at more realistic conditions. The assumption of constant exposure at peak temperature is believed to be conservative. Cumulative damage at more realistic conditions will likely be less severe but is more difficult to assess based on available data. Arrhenius aging behavior is expected, but non-Arrhenius behavior is possible. Validation of Arrhenius behavior is ideally determined from longer tests at temperatures closer to actual service conditions. CSR experiments will therefore continue at lower temperatures to validate the model. Ultrasensitive oxygen consumption analysis has been shown to be useful in identifying non-Arrhenius behavior within reasonable test periods. Therefore, additional experiments are recommended and planned to validate the model.« less

This report documents the review of Application for Contents Amendment for Shipping Isentropic Compression Experiment (ICE) Apparatus in 9977 Packaging, prepared by Savannah River Packaging Technology (SRPT) of Savannah River National Laboratory (SRNL) of Savannah River Nuclear Solutions, LLC, -- the Submittal -- at the request of the Department of Energy's (DOE) National Nuclear Security Agency's (NNSA) Albuquerque Facility Operations Division, for the shipment of the ICE apparatus from Los Alamos National Laboratory (LANL), to Sandia National Laboratory (SNL). The ICE apparatus consists of a stainless steel assembly containing about 8 grams of {sup 239}Pu or its dose equivalent as noted in Table 1, Comparison of 9977 Content C.1 and the ICE Radioactive Contents, of the Submittal. The ICE target is mounted on the transport container assembly base. A Viton{sup R} O-ring seals the transport container base to the transport container body. Another Viton{sup R} O-ring seals the transport container handle to the transport container body. The ICE apparatus weighs less than 30 pounds and has less than 0.6 watts decay heat rate. For the Model 9977 Package, the maximum payload weight is 100 pounds and the maximum decay heat rate is 19 watts. Thus, the maximum payload weight andmore » the maximum decay heat rate for the Model 9977 Package easily bound those for the ICE apparatus. This Addendum supplements the Safety Analysis Report for Packaging (SARP), Revision 2, for the Model 9977 Package and Addendum 1, Revision 2, to Revision 2 of the Model 9977 Package SARP. The ICE apparatus is considered as part of Content Envelope C.6, Samples and Sources, under the submittal for the Model 9978 Package SARP currently under review. The Staff at Lawrence Livermore National Laboratory (LLNL) recommends that the Submittal be approved by the DOE-Headquarters Certifying Official (EM-60), and incorporated into a subsequent revision to the current Certificate of Compliance (CoC), to the Model 9977-96 Packaging.« less

Isentropic compression experiments and numerical simulations on LX-04 (HMX / Viton 85/15) were performed respectively at Z accelerator facility from Sandia National Laboratory and at Lawrence Livermore National Laboratory in order to study the isentrope and associated Hugoniot of this HE [1][2][3][4][5]. 2D and 3D configurations have been calculated here to test the new beta version of the electromagnetism package coupled with the dynamics in Ls-Dyna and compared with the ICE Z shot 1067 on LX 04. The electromagnetism module is being developed in the general-purpose explicit and implicit finite element program LS-DYNA{reg_sign} in order to perform coupled mechanical/thermal/electromagnetism simulations. The Maxwell equations are solved using a Finite Element Method (FEM) for the solid conductors coupled with a Boundary Element Method (BEM) for the surrounding air (or vacuum). More details can be read in the reference [6][7].

Compatibility and outgassing studies of non-nuclear materials were carried out in support of the W80 Life Extension Program. These studies included small-scale laboratory experiments as well as participation in Sandia's Materials Aging and Compatibility test (MAC-1). Analysis of the outgassing signature of removable epoxy foam (REF) revealed unusually high levels of volatile organic compounds in the material. REF was replaced with the polyurethane PMDI. Laboratory compatibility tests of high priority materials were performed and revealed incompatibilities between Viton A (LX-07 binder) and syntactic polysulfide as well as Viton A and REF. With the removal of REF from the system, the incompatibility with Viton A is not an issue. In the case of the viton/polysulfide, both of these materials have a history of reliability in the stockpile, and the observed results, while scientifically interesting, appear to be a laboratory anomaly. Participation in the MAC-1 test led to a detailed study of Viton A degradation. At elevated temperatures up to 70 C, the Viton A samples darkened and exhibited increased crosslinking. Laboratory experiments were pursued to correlate the observed changes to exposure to specific compounds that were present in the MAC-1 canister atmospheres. Exposure to siloxanes resulted in changes similar to thosemore » seen in the MAC-1 samples. Knowledge gained from the MAC-1 test will be applied to the upcoming MAC-2 test planned for FY06. Finally, the suitability of isotopically labeled nitrogen fill gas ({sup 15}N{sub 2}) was addressed. This gas will behave as standard nitrogen with no compatibility concerns expected.« less

Synopsis of project activity: 1998--Awarded cost share grant from DOE. 1st Qtr 1999--Developed fail safe lubricating system. 2nd Qtr 1999--Performed first large scale test with nitrile based bearings. It failed due to material swelling. Failure was blamed on improper tolerance. 3rd Qtr 1999--Material tests were performed with autoclaves and exposure tests to Casa Diablo fluids. Testing of Viton materials began. Alternate bearing designs were developed to limit risk of improper tolerances. 4th Qtr 1999--Site testing indicated a chemical attack on the bearing material caused the test failure and not improper bearing tolerance. 1st Qtr 2000--The assistance of Brookhaven National Laboratory was obtained in evaluating the chemical attack. The National Laboratory also began more elaborate laboratory testing on bearing materials. 2nd Qtr 2000--Testing indicated Viton was an inappropriate material due to degradation in Casa Diablo fluid. Testing of EPDM began. 3rd Qtr 2001--EPDM bearings were installed for another large scale test. Bearings failed again due to swelling. Further testing indicated that larger then expected oil concentrations existed in lubricating water geothermal fluid causing bearing failure. 2002-2003--Searched for and tested several materials that would survive in hot salt and oil solutions. Kalrez{reg_sign}, Viton{reg_sign}ETP 500 and Viton{reg_sign}GF were identified as possible candidates. 2003-2005--Kalrez{reg_sign}hasmore » shown superior resistance to downhole conditions at Casa Diablo from among the various materials tested. Viton ETP-500 indicated a life expectancy of 13 years and because it is significantly less expensive then Kalrez{reg_sign}, it was selected as the bearing material for future testing. Unfortunately during the laboratory testing period Dupont Chemical chose to stop manufacturing this specific formulation and replaced it with Viton ETP 600S. The material is available with six different fillers; three based on zinc oxide and three based on silicon oxide. Samples of all six materials have been obtained and are being tested at the National Laboratory in Brookhaven, New York. This new material's properties as a bearing material and its ability to adhere to a bearings shell must be reviewed, but cost information deemed the material to be too expensive to be economical.« less

Results are reported for a project testing the capabilities of a mass spectrometer-based system for analyzing in-situ organic compounds on a variety of substrates. The system, which was built and operated at Lawrence Livermore National Laboratory (LLNL), is termed a Contamination Analysis Unit (CAU) and employs vacuum and thermal desorption of surface residues, followed by ionization and analysis with a Leybold Inficon Transpector mass spectrometer. The CAU was employed in this study to examine soils, cleaner residues, and substrates on Space Shuttle Reusable Solid Rocket Motor (RSRM) components. Project work was supported by ATK Thiokol Propulsion. Major project objectives include: (1) Determine residual propellant and liner components with the CAU after test coupons have been cleaned. (2) Determine if the CAU can detect solvent that has soaked into NBR insulation material, and if possible, determine the time following solvent application during which the cleaning agent is detectable. (3) Test CAU capabilities for analyzing non-flat surfaces on the inside and outside surfaces of the RSRM (12-foot diameter), and nozzle throat housing surfaces (5-foot diameter). (4) Determine if solvent extraction and gas chromatography (GC) approaches are able to enhance the surface analysis data available through use of the mass-spectrometer-based CAU. (5) Determinemore » the CAU's detection limit for various soils and cleaners. (6) Determine if contact of both Viton and silicon O-rings with critical substrates will result in any visual evidence of the contact, when observed under black light. (7) Demonstrate CAU viability during routine Thiokol manufacturing operations.« less

Water samples previously acquired from superheated (>140 C) zones within hydrological test boreholes of the Drift Scale Test (DST) show relatively high fluoride concentrations (5-66 ppm) and low pH (3.1-3.5) values. In these high temperature regions of the rock, water is present superheated vapor only--liquid water for sampling purposes is obtained during the sampling process by cooling. Based on data collected to date, it is evident that the source of the fluoride and low pH is from introduced man-made materials (Teflon{trademark} and/or Viton{trademark} fluoroelastomer) used in the test. The test materials may contribute fluoride either by degassing hydrogen fluoride (HF) directly to produce trace concentrations of HF gas ({approx}0.1 ppm) in the high temperature steam, or by leaching fluoride in the sampling tubes after condensation of the superheated steam. HF gas is known to be released from Viton{trademark} at high temperatures (Dupont Dow Elastomers L.L.C., Elkton, MD, personal communication) and the sample water compositions indicate near stoichiometric balance of hydrogen ion and fluoride ion, indicating dissolution of HF gas into the aqueous phase. These conclusions are based on a series of water samples collected to determine if the source of the fluoride is from the degradation of materials originally installedmore » to facilitate measurements. Analyses of these water samples show that the source of the fluoride is the introduced materials, that is the Viton{trademark} packers used to isolate test zones and/or Teflon{trademark} tubing used to draw water and steam from the test zones. In particular, water samples collected from borehole (BH) 72 high temperatures ({approx} 170 C) prior to introduction of any Viton{trademark} or Teflon{trademark} show pH Values (4.8 to 5.5) and fluoride concentrations well below 1 ppm over a period of six months. These characteristics are typical of condensing DST steam that contains only some dissolved carbon dioxide generated by water-mineral-gas reactions in the rock. With the introduction of the Viton{trademark} packer materials and Teflon{trademark} sampling tube in BH72, the water samples show pH values drop to 3.8, while fluoride rises to 2.4 ppm within three days. After nine days, the pH values reach as low as 3.4 and fluoride concentrations rise as high as 7.5 ppm in the collected samples. The background information describing the fluoride issue and a summary of the water collection activities along with the analytical results are provided below. The results of the field test confirm the hypothesis that the source of the fluoride in specific samples from the DST is the introduced test materials (i.e. Viton{trademark} and/or Teflon{trademark}). This is positive from the perspective of repository performance, particularly waste package and drip shield degradation behavior, as deleterious introduced materials would be avoided in an operating repository. Ongoing laboratory testing to be Completed in January 2002, and additional testing in BH72 and BH55 will address further details, such as the specific material introducing the fluorine and the material breakdown process.« less

The oblique impact test series on LX-10-0 Lot 710-2 was completed. Two instrumented oblique impact tests were done using RX-04-DW dropped at 45{degrees}, 5{prime} on a smooth steel surface. One additional oblique impact using RX-04-EB at 45{degrees} 3.5{prime} was done. An instrumented vertical drop and oblique impact series was begun on RX-04-EC (96/4 HMX/Viton).

The Materials Consultation Group of SRTC has completed a review of existing literature and data regarding the useable service life of Viton{reg_sign} GLT fluoroelastomer O-rings currently used in the Model 9975 packaging assemblies. Although the shipping and transportation period is normally limited to 2 years, it is anticipated that these packages will be used for longer-term storage of Pu-bearing materials in KAMS (K-Area Materials Storage) prior to processing or disposition in the APSF (Actinide Packaging and Storage Facility). Based on the service conditions and review of available literature, Materials Consultation concludes that there is sufficient existing data to establish the technical basis for storage of Pu-bearing materials using Parker Seals O-ring compound V835-75 (or equivalent) for up to 10 years following the 2-year shipping period. Although significant physical deterioration of the O-rings and release of product is not expected, definite changes in physical properties will occur. However, due to the complex relationship between elastomer formulation, seal properties, and competing degradation mechanisms, the actual degree of property variation and impact upon seal performance is difficult to predict. Therefore, accelerated aging and/or surveillance programs are recommended to validate the assumptions outlined in this report and to assess the long-term performance of O-ringmore » seals under actual service conditions. Such programs could provide a unique opportunity to develop nonexistent long-term performance data, as well as address storage extension issues if necessary.« less

Effects caused by stimulating once-shocked, weathered high explosives (OSW-HE) are investigated. The sensitivity of OSW-HE to mechanical stimuli was determined using standard industry tests. Some initial results are given. Pieces of OSW-HE were collected from active and inactive firing sites and from an area surrounding a drop tower at Los Alamos where skid and spigot tests were done. Samples evaluated were cast explosives or plastic bonded explosive (PBX) formulations containing cyclotrimethylenetrinitramine (RDX), cyclotetramethylene tetranitramine (HMX), 2,4,6-trinitrotoluene (TNT), mock or inert HE [tris(beta-chloroethyl)phosphate (CEF)], barium nitrate, cyanuric acid, talc, and Kel-F. Once-shocked, weathered LX-10 Livermore explosive [HMX/Viton A, (95/5 wt %)], PBX 9011 [HMX/Estane, (90/10 wt %)], PBX 9404 [HMX/nitrocellulose, tris(beta-chloroethyl) phosphate, (94/3/3 wt %)], Composition B or cyclotol (TNT/RDX explosives), and PBX 9007 (90% RDX, 9.1% styrene, 0.5% dioctyl phthalate, and 0.45 resin) were subjected to the hammer test, the drop-weight impact sensitivity test, differential thermal analysis (DTA), the spark test, the Henkin`s critical temperature test, and the flame test. Samples were subjected to remote, wet cutting and drilling; remote, liquid-nitrogen-cooled grinding and crushing; and scanning electron microscope (SEM) surface analyses for morphological changes.

A program for evaluating packaging components that may be used in transporting mixed-waste forms has been developed and the first phase has been completed. This effort involved the screening of ten plastic materials in four simulant mixed-waste types. These plastics were butadiene-acrylonitrile copolymer rubber, cross-linked polyethylene (XLPE), epichlorohydrin rubber, ethylene-propylene rubber (EPDM), fluorocarbon (Viton or Kel-F), polytetrafluoroethylene, high-density polyethylene (HDPE), isobutylene-isoprene copolymer rubber (butyl), polypropylene, and styrene-butadiene rubber (SBR). The selected simulant mixed wastes were (1) an aqueous alkaline mixture of sodium nitrate and sodium nitrite; (2) a chlorinated hydrocarbon mixture; (3) a simulant liquid scintillation fluid; and (4) a mixture of ketones. The testing protocol involved exposing the respective materials to 286,000 rads of gamma radiation followed by 14-day exposures to the waste types at 60{degrees}C. The seal materials were tested using vapor transport rate (VTR) measurements while the liner materials were tested using specific gravity as a metric. For these tests, a screening criterion of 0.9 g/hr/m{sup 2} for VTR and a specific gravity change of 10% was used. Based on this work, it was concluded that while all seal materials passed exposure to the aqueous simulant mixed waste, EPDM and SBR had the lowest VTRs. In themore » chlorinated hydrocarbon simulant mixed waste, only Viton passed the screening tests. In both the simulant scintillation fluid mixed waste and the ketone mixture simulant mixed waste, none of the seal materials met the screening criteria. For specific gravity testing of liner materials, the data showed that while all materials with the exception of polypropylene passed the screening criteria, Kel-F, HDPE, and XLPE offered the greatest resistance to the combination of radiation and chemicals.« less

Nine variations of the formulation previously selected (HMX/Viton/Al) were tested during the quarter for a slow explosive to be used in a PBX lens systems. All but two showed stable velocities in a 1-inch diameter by 5-inch long rate stick; one appears to have a velocity which will approach a velocity index of 1.5 with LX-04.

The oblique impact sensitivity of UK-UK-simulated HMX in 85 to 90% formulation with Viton is not enough lower, if any, to encourage richer formulations or change to Bridgewater processes for this reason alone. Fifty-pound cyclotol 75/25 hemispheres gave moderate reactions (No. 4) as low as 3.5 foot (14{degrees}); lower tests have not been performed yet. {open_quotes}Reduced-H.E.{close_quotes} pieces of PBX 9404, 2, 3, 4, and 5 inches thick, respectively, were tested at 1.75 foot (14{degrees}) resulting in a 6 reaction for the 5 inches thick piece while the remaining three pieces gave 0 reactions.

LX-04-1 is DOE`s safest ``creep resistant`` conventional high explosive (CHE) with excellent thermal and long term compatibility properties. Because LX-04-1 contains 15% Viton by weight, it exhibits outstanding resistance to mechanical stimuli such as could be encountered in an accident scenario at the Pantex Plant. A large energy fluence is required to initiate LX-04-1. The most likely methods to generate this energy into the individual cracked W70 HE is via dropping the unit onto the floor (or tooling) or the cracked HE rubbing against itself. In either case, not enough energy is available to cause the LX-04-1 to even mildly react as evidenced by the supporting data that follows. Experimenters have developed a number of sensitivity tests, each seeking to initiate reaction in a rigidly prescribed manner so that results from different investigators may be compared. Although it is possible for an explosive to exhibit high sensitivity on some tests and low sensitivity on others, LX-04-1 consistently shows low sensitivity to detonation on all tests. Table 1 compares the general stability and energy properties of LX-04-1 with PBX-9404 and LX-10-2.

A series of experiments at Los Alamos National Laboratory explored the efficacy of ammonium hydroxide solutions in converting HMX (cyclotetramethylene-tetranitramine, or Octogen) and HMX-based explosives to nonenergetic, nonhazardous materials. When 80 g of explosive was converted in a reactor operating at 85 psig pressure at 140 C, the principal gaseous products were nitrous oxide (46% to 51%), nitrogen (22% to 32%), and ammonia (17% to 28%). Formate and hexamethylene-tetramine (hexamine) account for effectively 100% of the carbon-bearing aqueous species. Nitrate, nitrite, and acetate were present in the liquid in trace amounts. The process effectively treated molding powders of the plastic-bonded explosives PBX 9501 (2.5% estane), LX-04 (15% viton), and PBX 9404 (3% nitrocellulose). Results were compared with those achieved using sodium hydroxide solutions at 150 C in a pressurized reactor.

In fiscal year 1993, tests of an o-ring/tetraseal retainer designed to replace a gasket-type seal used in PUREX-type process jumper connectors encouraged the design of an improved seal block. This new seal block combines several parts into one unitized component called an integral seal block. This report summarizes development and leak testing of the new integral seal block. The integral seal block uses a standard o-ring nested in a groove to accomplish leak tightness. This seal block eliminates the need to machine acme threads into the lower skirt casting and seal retainers, eliminates tolerance stack-up, reduces parts inventory, and eliminates an unnecessary leak path in the jumper connector assembly. This report also includes test data on various types of o-ring materials subjected to heat and pressure. Materials tested included Viton, Kalrez, and fluorosilicone, with some incidental data on teflon coated silicone o-rings. Test experience clearly demonstrates the need to test each seal material for temperature and pressure in its intended application. Some materials advertised as being {open_quotes}better{close_quotes} at higher temperatures did not perform up to expectations. Inspection of the fluorosilicone and Kalrez seals after thermal testing indicates that they are much more susceptible to heat softening than Viton.

This illustrative test was undertaken as a result of on-going failure of elastomer components in plutonium gloveboxes. These failures represent one of the major sources of required maintenance to keep gloveboxes operational. In particular, it was observed that the introduction of high specific activity Pu-238 into a glovebox, otherwise contaminated with Pu-239, resulted in an inordinate failure of elastomer components. Desiring to keep replacement of elastomer components to a minimum, a decision to explore a few possible alternative elastomer candidates was undertaken and reported upon herewith. Sample specimens of Neoprene, Urethane, Viton, and Hypalon elastomeric formulations were obtained from the Bacter Rubber Company. Strips of the elastomer specimens were placed in a plutonium glovebox and outside of a glovebox, and were observed for a period of three years. Of the four types of elastomers, only Hypalon remained completely viable.

The chemical compound benzene (C/sub 6/H/sub 6/) has a melting point of 5.5/sup 0/C, a boiling point of 80.1/sup 0/C, and is widely used as a solvent and chemical intermediate throughout the chemical, petrochemical, and associated industries. Although the toxic and carcinogenic natures of benzene have been known for some time, the strict 1 ppM regulation governing human exposure to it as a vapor or a liquid is relatively recent. Because of regulations and concern, the National Institute for Occupational Safety and Health requested that a study be performed to determine the rate at which liquid benzene would permeate certain protective garment materials. Accordingly, this work presents the results of such measurements on butyl, natural, neoprene, nitrile, surgical, Tyvek, vinyl and Viton rubbers and elastomers, and the following composites or supported elastomers: butyl-coated nylon, ethylene vinyl acetate/polyethylene-coated polyester, polyethylene-coated Tyvek, and polyvinyl alcohol. Included in these determinations were studies to correlate the protective clothing swelling or weight change following immersion in benzene with the actual rate at which the materials were permeated by benzene so that ultimately a screening test might be recommended concerning the permeation or lack of permeation through given materials.

TATB PBX growth was reduced significantly by using binders other than the Kel-F 800. Kraton G-6500 (a co-polymer of styrene and ethylenebutylene) and three polyester resins exhibited less growth than formulations containing Estane, Vistanex, and Viton A binders.

Viton rubber O rings to be used in the plasma-containment vessel of the ZT-40 torus were molded and tested for their sealing ability. To meet the stringent requirements for these parts, the mold design and mold surface preparation should adhere strictly to the Viton manufacturer's recommendations. In addition, the molding stock must be worked either by injection molding or by a preprocess such as extrusion.

Twenty candidate sealants representing ten different polymer types were evaluated as potential solar collector sealants. Polymer types tested included epichlorohydrin rubber, EPDM rubber, silicone, polysulfide, acrylate rubber, and a fluoroelastomer. Initial screening of sealants consisted of measuring high temperature stability and adhesion retention. Several sealant compositions exhibited satisfactory performance in these tests and were selected for further evaluation. These materials were based on an EPDM rubber, a Viton fluoroelastomer, and silicone polymers. Further testing of these candidate materials included determination of adhesion retention under uv/water/heat conditions, fogging temperature, low temperature flexibility, and physical properties. Four silicone-based materials appeared to be suitable candidates for sealing solar collectors. These include Dow Corning 90-006-02 and 3120, General Electric 1200, and PR-1939 from Products Research and Chemical Corporation.

A series of boron-filled vinyl copolymer elastomer (VCE) and Viton A fluoroelastomer formulations was prepared and the physical characteristics of the cured formulations determined. Their weight loss on heating to 300/sup 0/C, as determined by two different analytical methods, did not agree. The presence of up to 0.23 percent boric acid in the boron powders used to fill a standard boron-filled VCE elastomer did not appear to affect the physical characteristics of the cured formulation. 7 tables. (auth)

The halogenated ethanes 1,2-dichloroethane; 1,1,1-trichlorethane; and 1,1,2-trichlorethane are used as chemical intermediates and in metal working operations, and polychlorinated biphenyls (PCBs) have in the past been used by the tens of millions of pounds in various roles in American industry. Because of the widespread use and hazardous or potentially carcinogenic nature of these compounds, a study was performed to determine the degree of protection which was afforded against these compounds by certain protective garment materials. The materials evaluated in these studies have included: butyl rubber, milled nitrile rubber, neoprene rubber latex, nitrile rubber latex, polyethylene, poly(vinyl alcohol), surgical rubber latex, Teflon, and Viton as well as the following composite or multilayered materials: butyl-coated nylon, polyethylene-coated Tyvek, polyurethane-coated nylon, and poly(vinyl chloride)-coated nylon. The breakthrough time at which each liquid phase compound permeated these materials was studied by the time lag method. For the noncomposite materials, the results of these breakthrough studies were correlated with their equilibrium weight changes following immersion in the test liquids. Results of these studies have shown that most materials currently used in the construction of protective garment material in the United States are of a generally unsatisfactory nature with respect to protecting the worker against themore » halogenated ethanes and the PCB used in this study.« less

Equilibrium water vapor pressure and total moisture content were measured for samples of TATB-10 percent Kel-F, TATB-6 percent Estane, and TATB-9 percent Viton in a temperature range from 296 to 365/sup 0/K. Heats of vaporization were obtained for temperatures from 296 to 333/sup 0/K. Below 333/sup 0/K the water in the samples behaved as dissolved water and the Clausius-Clapeyron equation was applicable, while above 333/sup 0/K the water dissolved in the samples became very mobile and for practical purposes it was considered to be available in its entirety in the gas phase. The total moisture content of the samples was found to be

The development and testing of seals and lubricants for journal-type roller-cone rock bits for drilling into geothermal reservoirs at temperatures over 260/sup 0/C (500/sup 0/F) are described. The conditions experienced by seals and lubricants subjected to geothermal drilling are reviewed along with the basic design requirements for roller-cone bit seals and journal bearing lubricants. Two unique test facilities are described: a seal test machine which simulates pressures, temperatures, and mechanical eccentricities, and a lubricant tester capable of evaluating load-bearing ability at temperature and pressure. Three candidate elastomeric compounds demonstrated 288/sup 0/C (550/sup 0/F) capability and several others demonstrated 260/sup 0/C (500/sup 0/F) or greater capability. Successful elastomeric seal candidates were proprietary compounds based on EPDM, Kalrez, and/or Viton polymers. Three mechanical seals for reservoir temperatures over 288/sup 0/C (550/sup 0/F) are presented. Lubricant screening tests on more than 50 products are summarized, and several newly developed lubricants which meet both the compatibility and lubrication requirements are described. Several seal/lubricant systems are recommended for laboratory or field geothermal drilling tests in roller-cone drill bits. The future availability of drill bits for geothermal use is discussed, as well as the potential spinoffs of the program findings for nongeothermal roller-cone bits.

High temperature seals (elastomeric and mechanical) and lubricants were developed specifically for journal-type rock bits to be used in geothermal well drilling. Results at simulated downhole conditions indicate that five selected elastomeric seals (L'Garde No. 267, Utex Nos. 227, 231 and HTCR, and Sandia Glow Discharge Coated Viton) are capable of 288/sup 0/C (500/sup 0/F) service. Two prototype mechanical seals did not achieve the life determined for the elastomeric seals. Six lubricants (Pacer PLX-024 oil, PLX-043 oil, PLX-045 oil, Geobond Oil, and Geobond Grease) demonstrated 316/sup 0/C (600/sup 0/F) capability. Recommendation is made for full-scale simulated geothermal drilling tests utilizing the improved elastomeric seals and lubricants.

Samples of Kel-F 800, Viton A and Estane 5702-F1 were annealed at 323/sup 0/K and their crystallinity was tested by x-ray diffraction, thermal mechanical analysis, and differential scanning calorimetry. After annealing for three months, all three samples exhibited some crystalline properties.

Four batches of experimental PETN have been made for incorporation into LX-13 (Extex). A control batch was reprecipitated in the conventional manner (shock reprecipitation from acetone into violently agitated water) while three batches were made in the Micronizer: Two of these were treated with MRL 22A.with one of the treated batches being heat stabilized for 8 hours at 116 C. Two 500-pound batches of RX-04-EC (4% Viton A) were made to supply material for the special studies of the effects of deviations in the composition of LX-10 type explosive. An attempt was made to mold a skid test part from ECX. Inadequate curing of the binder made mold stripping difficult.

This report is the second compilation of methods for analyzing explosives. All the methods were developed for routine performance by techniques, and an attempt has therefore been made to keep them as simple as possible. Methods are presented for analyzing plastic-bonded explosives based on sym-cyclomethylenetetra-nitramine (HMX), based on viton in addition to HMX, and based on pentraerythritol tetranitrate (PETN).

Data from sieve analyses of HMX and HMX recovered from LX-04-1 has been compiled for correlation to quality parameters. Particle size distributions on HMX received from LRL have been completed along with other HMX lots specified by them. Sieve analysis of recrystallized PETN was obtained using the now normal procedure for HMX. A statistical investigation of production LX-04-1 examined the dependence of density, elongation, and ultimate tensile strength on particle size distributions ({Pi}) and Viton content. The {Pi} was found to correlate well with density, increases in fines decreasing density. An experimental to determine the effect of binder solvent on HMX {Pi} during removal of Viton from pressed LX-04-1 was performed. This study has indicated no drastic effect on the distribution by the length of time the binder solvent is on the material. HMX and recrystallized PETN surface area measurements obtained form the Perkin-Elmer sorptometer are tabulated in this report. Recrystallized PETN has been examined under the microscope and counts made on the number of crystals with given shape. A frequency distribution was calculated for each group present in a 1 mm{sup 2} area. Experiments to determine the extent of grinding or reduction of particle size of HMX agitated in an ultrasonic vibrator for increasing times have been done. The data have indicated a time of three--five minutes is adequate to disperse agglomerates without undue breaking or grinding of solid crystals. It is possible to do some grinding under severe conditions in the ultrasonic bath.

This project was initiated to study the manufacture of new explosive formulations. Production and quality parameters are determined; among these are viscosity, composition, particle size distribution, processing variables and raw materials, and their effect on operation, safety characteristics, producibility, and physical and explosive properties. Pastes, extrudables, and PBX`s are among the formulations. One 20-pound batch of XTX-8003 was made to complete a milling study and two 28-pound batches were made to fill an LRL order. No problems were encountered during the manufacturing operation, and test fire results were satisfactory. The effort to resolve some of the problems with LX-04 included evaluating reprocessing techniques and testing various binders. Outstanding elongation results were obtained with Fluorel 1700 binder. Also, a reasonably good elongation was obtained with Lot 16 Viton when the slurry coating was performed in the 100-gallon kettle. The washing and reworking, with extra solvent, of production Lot 27B improved elongation somewhat, but not enough for production acceptance.

The purpose of this project is to determine the thermal properties of explosives, and to continue the development and evaluation of thermal tests. Two preliminary experiments were conducted to determine (1) how the time-to-explosion (TE) using Lee Plugs (short stainless steel and aluminum) would compare with the TE obtained using the lead plugs; and (2) how the Lee Plugs would perform with du Pont`s EL-511 and Tacot at 314{degrees}C and 362{degrees}C., respectively. The Pantex-built chromatograph is operating as a two-column instrument, and the findings of an extensive check out of the instrument are reported. The chemical reactivity test sample holders were shown to evolve approximately 30{mu}l of N{sub 2} + O{sub 2} and 3 {mu}l of CO{sub 2} when heated for 22 hours. A number of thermal tests were made on two lots of LX-04-1 (39A and 38B) to determine if any differences could be detected that would explain why Lot 38B tensile strength is much better than 39A when both were made from the same lot of Viton A. Some differences were detected, but they have not been related to the tensile strength of the material. The time-to-explosion for various Adiprenes with HMX are reported, and they indicate that there could be some reactivity between the Adiprene and HMX. Pantex and LASL DTA thermograms and pyrolograms for PETN and Extex are reported for comparison to determine how the sensitivity of Pantex instruments compare with LASL, and if these instruments could be used to qualify PETN and Extex in accordance with LASL Specification 13Y-104481.