5
General Atomics Technology Package

DESCRIPTION OF THE PROCESS

The General Atomics Total Solution (GATS) technology package proposed for the Blue Grass Army Depot is based on and is very similar to the design General Atomics originally proposed for the treatment of assembled chemical weapons early in the ACWA program (NRC, 1999). General Atomics is the sole developer of the GATS process, including the designs of all of the munitions-processing and dunnage-processing equipment. The balance of the plant design and site infrastructure was prepared by the Parsons Infrastructure and Technology Group.

The specific GATS technology design evaluated by the committee is for the treatment of the particular inventory of agent-filled munitions stored at Blue Grass (i.e., M55 GB and VX rockets, 8-inch GB projectiles, and 155-mm VX and H projectiles). These munitions are described in Table 1-3. The GATS process is designed to treat agent, energetic materials, metal parts (including munitions bodies), dunnage (e.g., wooden pallets and packing boxes used to store munitions), and nonprocess waste—the last-mentioned includes plastic demilitarization protective ensemble (DPE) suits; the carbon from DPE suit filters and plant heating, ventilating, and air-conditioning (HVAC) filters; and miscellaneous plant wastes.

The following discussion of the GATS process is based on Figure 5-1, which identifies the steps of the GATS process designed for a facility at Blue Grass Army Depot (General Atomics, 2001a).1

Disassembly of Munitions

Steps 1, 3, and 4 of the GATS process (Figure 5-1) incorporate comparatively minor modifications to existing baseline system procedures for the reverse assembly of munitions. These procedures were used at the baseline incineration system disposal facilities at Johnston Atoll (in the Pacific Ocean) and Tooele, Utah, where the Army has accumulated more than 10 years of experience in their operation. Rockets are processed by two rocket shear machines (RSM), each operating at the rate of 10 rockets per hour. The rockets are first punched and drained of agent, then flushed with hot water to remove any gelled agent. The flush operation is an addition to the GATS process. After agent removal, the rockets are sheared by the RSM into nine segments to access the fuze, burster, and rocket motor propellant. The sheared segments are transferred to the energetics rotary hydrolyzer (ERH).

Not all the projectiles in storage at Blue Grass Army Depot contain explosive burster charges. Those projectiles with bursters (155-mm HD rounds) are pro-

1  

Note that the step numbers for the Blue Grass design have been modified and reordered from those identified for the GATS process designed for Pueblo Chemical Depot and given in NRC (2001a).



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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot 5 General Atomics Technology Package DESCRIPTION OF THE PROCESS The General Atomics Total Solution (GATS) technology package proposed for the Blue Grass Army Depot is based on and is very similar to the design General Atomics originally proposed for the treatment of assembled chemical weapons early in the ACWA program (NRC, 1999). General Atomics is the sole developer of the GATS process, including the designs of all of the munitions-processing and dunnage-processing equipment. The balance of the plant design and site infrastructure was prepared by the Parsons Infrastructure and Technology Group. The specific GATS technology design evaluated by the committee is for the treatment of the particular inventory of agent-filled munitions stored at Blue Grass (i.e., M55 GB and VX rockets, 8-inch GB projectiles, and 155-mm VX and H projectiles). These munitions are described in Table 1-3. The GATS process is designed to treat agent, energetic materials, metal parts (including munitions bodies), dunnage (e.g., wooden pallets and packing boxes used to store munitions), and nonprocess waste—the last-mentioned includes plastic demilitarization protective ensemble (DPE) suits; the carbon from DPE suit filters and plant heating, ventilating, and air-conditioning (HVAC) filters; and miscellaneous plant wastes. The following discussion of the GATS process is based on Figure 5-1, which identifies the steps of the GATS process designed for a facility at Blue Grass Army Depot (General Atomics, 2001a).1 Disassembly of Munitions Steps 1, 3, and 4 of the GATS process (Figure 5-1) incorporate comparatively minor modifications to existing baseline system procedures for the reverse assembly of munitions. These procedures were used at the baseline incineration system disposal facilities at Johnston Atoll (in the Pacific Ocean) and Tooele, Utah, where the Army has accumulated more than 10 years of experience in their operation. Rockets are processed by two rocket shear machines (RSM), each operating at the rate of 10 rockets per hour. The rockets are first punched and drained of agent, then flushed with hot water to remove any gelled agent. The flush operation is an addition to the GATS process. After agent removal, the rockets are sheared by the RSM into nine segments to access the fuze, burster, and rocket motor propellant. The sheared segments are transferred to the energetics rotary hydrolyzer (ERH). Not all the projectiles in storage at Blue Grass Army Depot contain explosive burster charges. Those projectiles with bursters (155-mm HD rounds) are pro- 1   Note that the step numbers for the Blue Grass design have been modified and reordered from those identified for the GATS process designed for Pueblo Chemical Depot and given in NRC (2001a).

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot FIGURE 5-1 GATS Blue Grass block flow diagram. SOURCE: General Atomics, (2001a).

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot cessed through a single projectile mortar demilitarization (PMD) machine, which removes the whole bursters. Unlike the GATS process described in the ACW II Committee’s report for Pueblo, the bursters removed from the munitions are not sheared as in the baseline system but are transferred directly to the ERH (NRC, 2001a; General Atomics, 2001a). Projectiles without burster charges do not go through the PMD. There are no propellant materials for the projectiles at Blue Grass. Dunnage Separation, Shredding, Grinding, and Slurrying Step 2 is the separation, shredding, and grinding of dunnage and nonprocess wastes. The dunnage shredding and handling system (DSHS) incorporates three subsystems to process (1) wood, originating mainly from pallets, (2) plastic and rubber from DPE suits, and (3) the activated carbon from respirators and from the plant’s numerous carbon filters. The design is based on the assumption that all dunnage and nonprocess wastes are contaminated with agent. The organic materials (e.g., wood, paper, rubber, plastic, metal-free DPE suit material, and spent carbon) are reduced in a series of steps to a particle size of less than 1 mm. The resulting dry material is placed in storage bins from which it is fed into the two commercial hydropulpers, described in Step 9. The resultant slurried material is subsequently transferred via a grinding pump to the high-pressure pumps that feed the SCWO reactors. The wood, plastic and rubber, and spent carbon materials are processed in three separate equipment lines, but the respective fine slurry materials are mixed with energetics hydrolysate to make feed for the SCWO reactors. Wood shredding is itself a four-step process. Pallets and similar dunnage materials are sheared in a low-speed shredder. This is followed by a Komar reducing screw feeder, which also equalizes the downstream flow. The dunnage materials are then further size-reduced in a hammer mill. Metal components, such as nails, are removed by magnetic head pulleys both after the low-speed shredder and after the hammer mill. The metal goes to the heated discharge conveyor (HDC) (Step 16) for 5X decontamination. In the fourth step, the milled wood with the metal removed is ground to less than 1 mm in a micronizer whose design includes a baghouse for dust control. DPE suits are treated by the following steps. Metal parts are manually cut and removed from each DPE suit when the worker is cut out of the suit upon exiting a Category A area. The metal fittings are sent for 5X decontamination to the HDC that treats metal munition parts from the projectile agent removal system (Step 16). The metal-free DPE suit material is fed to a two-stage size-reduction system. In this operation, the material is first shredded to less than 10 mm in a dedicated granulator. Tests showed that further mechanical size-reduction in the granulator was ineffective because the polyvinyl chloride suit material melted rather than tearing. Therefore, after granulation, the DPE material is reduced to less than 1 mm in a cryomicronizer with a liquid-nitrogen-cooled screw feeder. The micronized wood and DPE are mixed together with energetics hydrolysate and spent decontamination solution in hydropulpers (Step 9) and processed through the SCWO reactors of the energetics hydrolysis system. The spent activated carbon from plant HVAC filters and from respirators is first heat-treated in a heated, helical screw conveyor to drive off agent and is then reduced to less than 0.5 mm in a wet spent carbon grinder. Offgas from the processing of the carbon will be treated by the gas treatment system of either the projectile rotary hydrolyzer (PRH) or the ERH. The micronized carbon is mixed with water in the hydropulper (Step 9) and separately processed through the SCWO reactors of the energetics hydrolysis system. Hydrolysis of Energetic Materials In Step 5, energetic materials and associated metal parts from the PMD machine and RSM operations are sent to the ERH, a long, steam-jacketed rotating cylinder with internal spiral flights and lifting flights where the hydrolysis of energetics begins. The hydrolysate from the ERH then goes to continuously stirred tanks in which the hydrolysis is completed. The design for Blue Grass calls for two ERH systems. Table 5-1 lists design parameters for the ERH (and the PRH discussed in Step 8). Hot water and sodium hydroxide solution, along with the energetic materials and associated metal parts, are fed into the ERH at one end and flow concurrently through the rotating cylinder. The liquid in the ERH drum is maintained at a minimum depth of 24 inches. Hydrolysis of the energetic materials by the caustic leaves only small pieces of residual energetics, as shown during the EDS tests. The energetics feed rate is maintained to keep the explosive loading in the ERH to

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot TABLE 5-1 Key Design Parameters for GATS ERH and PRH Parameter ERH PRH Residence time (hr) 5 1 Drum diameter (ft) 8 6 Drum length (ft) 50 40 Flight (ft/pitch) Spiral, 2.5 Spiral, 2.5 Nominal rotational speed (rotations/hr) 4 16 Operating temperature 105°C (bursters), 120°C (rockets) 194°F (90°C) Operating pressure Negative 0.5-inch water column to ambient Negative 0.5-inch water column to ambient NaOH (dry weight) (lb/lb propellant) 6.5 (7.3 × stoichiometric)   (lb/lb explosives) 0.83 (1 × stoichiometric)   (lb/lb aluminum) 1.482 (1 × stoichiometric)   Liquid flow direction Cocurrent Countercurrent   SOURCE: Adapted from General Atomics (2001a). less than 17.5 pounds TNT equivalent; the system is designed to safely contain an accidental detonation of this size. The solids residence time is approximately 5 hours, a time that was shown during Demo I and EDS testing to be sufficient for the essentially complete hydrolysis of rocket propellant in the original aluminum casing. Because of their large size and the metal casing, these chunks of propellant are considered by the designers (and by the committee) to represent worst-case conditions for processing by the ERH. The ERH has two types of flights, spiral and lifting. The spiral flights transport material axially along the cylinder. The lifting flights slowly agitate the hydrolyzing solution and the solids. The drum is steam-jacketed to maintain the ERH contents at the desired temperature for the particular energetic materials being processed. The ERH is operated as a single-temperature-zone reactor when processing parts from projectiles and as a two-temperature-zone reactor when processing rocket parts. For projectile processing, the temperature is maintained along the entire ERH length at 110°C. Because this is above the melting temperature of the TNT in the bursters, hydrolysis occurs rapidly in the caustic solution. The hydrolysis solution is maintained at 8 M NaOH at the feed inlet, and the feed rate is controlled to match the feed rate of the projectile bursters. For rocket processing, the ERH is divided into two zones. The first part of the reactor, nominally 10 feet, is initially fed 4 M (14 weight percent) NaOH with the temperature kept at 105°C to accommodate the relatively quick dissolution of the aluminum and burster material. The residence time in the first 10 feet of the reactor is 1 hour. To handle the slower hydrolysis rate of the propellant, the remaining 40-foot section of the reactor—the second zone—is operated at high caustic concentrations and temperatures. Additional NaOH solution (50 weight percent) is added to the ERH through a pipe 8 feet from the feed inlet to raise the caustic concentration to 13 M (37 weight percent). The second zone is kept at 120°C. At the discharge end of the ERH, the slurry is drained through a perforated section into a sump. The solid materials, which include unreacted fuze components, segments of fiberglass and steel casings from rocket motors, small quantities of residual rocket propellant, and steel burster tubes and nose closures, are lifted out of the solution by the spiral flights and fed into a chute leading directly onto the HDC, discussed in Step 13, for 5X decontamination. The slurry from the ERH sump is pumped to one of two continuously stirred reactors (two for each ERH, four for the plant) to complete the hydrolysis, if necessary. Because the sodium hydroxide dissolves any aluminum present in the munitions, converting it to aluminum hydroxide, the aluminum hydroxide is prevented from clogging downstream components by neutralizing the completely reacted hydrolysate with hydrochloric or sulfuric acid, causing the dissolved aluminum to form a precipitate, which is then filtered (Step 7). The hydrolysate is sent to holding tanks to await secondary treatment in the SCWO reactors. Air is drawn through the ERH to remove fumes, including particulate, mist, and the hydrogen produced

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot from the hydrolysis of aluminum in the munitions, and to dilute the offgas to well below the lower explosive limit (LEL). The principal constituents of the ERH gas stream are these: ventilation air (room air), which is used to dilute hydrogen in the ERH nitrogen, which is used to purge the HDC water vapor, which evaporates from the hydrolysate in the ERH drum organic gases that evolve during the hydrolysis process, including nitroglycerine and nitrosodiphenylamine The vent gas from the ERH flows through an electrically heat-traced duct (to prevent condensation) into an electric heat exchanger that raises its temperature to 260°C (500°F) and then into a CATOX unit to destroy residual organic contaminants. The gas is then cooled to between 12°C and 15°C (60°F) in a scrubber/condenser that removes additional contaminants. The gas then flows through an induced draft fan, discharging into the plant’s HVAC system. The pressure in the ERH is continuously monitored at the vent gas exit duct of the ERH drum to ensure that it operates at subatmospheric pressure. In addition, the hydrogen gas concentration is measured in the ERH drum vent gas exit duct to ensure that hydrogen gas concentration remains below 50 percent of its LEL. Signals from these monitors are used to control the ventilation gas flow by changing the speed of the induced draft fan. Cryofracture of Munitions Step 6 of the GATS process is the projectile agent removal system. After the energetic materials and associated metal parts have been removed and sent to the ERH, the agent cavity of the munition body is accessed by a cryofracture process. Cryofracturing involves first embrittling the munition by cooling it in a liquid nitrogen bath (77 K, ̱−321°F, ̱−196°C) and then transferring it via an overhead robot to a hydraulic press that cracks open the agent cavity, thereby exposing the frozen, solidified, or gelled agent and agent heels. The cracked, frozen agent and munitions go to the PRH (Step 8), which is discussed below. The cryocooling bath is modeled after commercial food-freezing tunnels. Key design parameters for each cryofracture train are given in Table 5-2. Projectiles TABLE 5-2 Key Design Parameters for Each GATS Cryofracture Train Parameter Value Cryocooling conveyor (two trains)   Dimension (ft) 25 (L) × 5 (W) × 4 (H) approx. Max speed (ft/min) 0.75 Capacity 20 munitions (in each bath) Liquid N2 capacity (gal) 2,000 (in each bath) Munition residence (min) 40, in bath Cryofracture press (one train)   Tonnage (tons) 500 (24-inch stroke) Cycle time (sec) 30 Ventilation air flow (lb/hr) 4,800 Liquid nitrogen usage boil-off 1 lb liquid nitrogen/lb munition+ 400 lb/day Flush water per fracture (gal) 1.0   SOURCE: Adapted from General Atomics (2001a). and mortars (minus energetic components) are conveyed from the PMD machine ECR to the cryobath loading station in a horizontal orientation. A cryobath loading robot places each round onto a moving link belt that conveys the munitions completely submerged through the liquid nitrogen bath. The residence time in the liquid nitrogen is sufficient to freeze the munition and associated agent to the temperature of liquid nitrogen. At the discharge end, the belt lifts the munitions out of the bath, and the unloading robot places it onto the anvil of the cryopress (hydraulic press). The press base is a tilt table that sends the cracked munitions into a discharge chute, which in turn sends both the metal and frozen agent into the feed chute of the PRH. Residual material, including any melted agent, is flushed from the cryopress with hot water into the PRH along with the remaining munitions components. Test data appear to indicate that the cryopress operation provides good removal of the agent from the munition body and improves the accessibility of the hydrolysis solution in the PRH to the metal surfaces of the agent cavity (General Atomics, 1993). The cryofracture system for cracking chemical weapons was developed and tested by General Atomics for the Army during a test program that is discussed later in the chapter. Munitions-processing bay-bridge robots, as used in the baseline system, have been fitted with new end effectors for loading and harvesting mu-

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot nitions from the cryobath and transferring them into the cryopress. Aluminum Precipitate Filtration In Step 7, after the energetics hydrolysate from the continuously stirred tank hydrolysis operation has been pumped into a holding tank, acid is added to precipitate aluminum, and the hydrolysate is filtered through an automatic filter press to remove precipitated aluminum compounds. The liquid effluent goes to the dunnage hydropulper (Step 9). The filter cake from the press is sent to an electrically heated screw conveyor (Step 15) for 5X treatment. Projectile Rotary Hydrolyzer In Step 8, accessed frozen agent is hydrolyzed with hot caustic (when processing GB and VX) or hot water (when processing HD), and agent-contaminated metal parts from the cryofracturing step are washed in one of two PRHs. The PRHs are smaller but similar in function and construction to the two ERHs (see Table 5-1). The liquid flow in the PRH is countercurrent to the flow of solids. The PRHs are externally steam heated to maintain the temperature at the desired level. The drum of the PRH is fitted with a spiral flight and lifting flights to transport and mix the munition fragments axially along the drum from feed to discharge. A stationary shell of thermal insulation encloses the drum. Depending on the agent being processed, either caustic (GB and VX) or hot water (HD) is introduced at the discharge end and flows countercurrent to the stream of solids. The liquid, which dissolves the frozen agent and/or agent heels, is discharged through a screen at the feed end of the PRH, separating the solution from the freshly introduced metal fragments. At the discharge end, the lifting flights lift the metal fragments out of the solution onto a chute leading to an HDC, which is distinct from but similar to the HDC to which ERH materials are discharged. The PRH hydrolysate is discharged to a stirred tank, where the hydrolysis of agent is completed. Air is drawn through the PRH to remove volatile materials, and the gaseous effluent is passed through a CATOX, scrubber, and carbon filters prior to release to the plant’s HVAC system. The solids, consisting of the washed munitions parts, go into the HDC that treats metal parts from the projectile agent removal system (Step 16), where they are decontaminated to a 5X level. Dunnage Hydropulping In Step 9 of the GATS process, the dry, size-reduced dunnage materials and nonprocess wastes from Step 2 are slurried with energetics hydrolysate in preparation for feeding to one of the SCWO reactors. Following the removal of precipitated aluminum compounds by filtration in Step 7, the energetics hydrolysate is transferred to one of two hydropulpers. Spent decontamination solution used in various decontamination operations in the plant also goes to the hydropulper tanks. In the hydropulpers, the ERH hydrolysate fluid is mixed with the dry material produced from shredding and micronizing the organic dunnage and other waste materials to produce a slurry. Additional water or a dilute solution of NaOH is added as needed to adjust water content, neutralize any residual agent, and otherwise adjust the slurry to meet the feed requirements of the SCWO reactors. Proprietary additives are used to ensure that the solids remain in suspension and that the slurry can be reliably pumped and processed in the SCWO reactor system (Step 11). The hydropulper tanks are continuously stirred and periodically sampled prior to transfer of their contents to an energetics hydrolysate slurry storage tank, from which the slurried dunnage and neutralized energetics are pumped to the SCWO reactors. Completion of Agent Hydrolysis In Step 10, the agent drained from rockets or the PRH hydrolysate solution (and any residual agent) is transferred to one of the four batch reactor vessels of the projectile agent hydrolysis system. These vessels, equipped with high-shear agitators and containing caustic solution (or water when processing agent HD), complete the hydrolysis of the agent drained from rockets or the remaining agent in the PRH hydrolysate solution. The hydrolysate then is stored in the vessel pending verification of agent destruction. These reactor vessels are similar in design to the ones that will be used in the hydrolysis of bulk mustard agent at the Aberdeen Chemical Agent Disposal Facility. See Table 5-3 for key design parameters of the neutralization system tanks. Treatment by Supercritical Water Oxidation Step 11 of the GATS process is treatment of the hydropulped dunnage slurried with energetics hydroly-

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot TABLE 5-3 Key Design Parameters for the GATS Projectile Agent Hydrolysis System Mustard (HD) agent hydrolysis • Eight 6,428-lb, 15-wt% HD agent /water batches per day . . . • Following confirmation of agent destruction, HCl is neutralized with sodium hydroxide. • Batch hydrolysis at 194°F • Reaction time 1½2 hr • Total batch time 5½2 hr Sarin (GB) agent hydrolysis • Eight 5,205-lb, 7-wt% GB agent /NaOH batches per day . . . • Batch hydrolysis at 120°F • Reaction time 2 hr • Total batch time 5 hr VX agent hydrolysis • Three, 5,104-lb, 22.7-wt% VX agent /NaOH batches per day . . . • Batch hydrolysis at 194°F • Reaction time 5 hr • Total batch time 11 hr   SOURCE: This table was reproduced from General Atomics (2001a). The committee has omitted the chemical equations because they were not balanced and some formulae were inaccurate. sate by SCWO. Step 12 is the treatment of agent hydrolysate by SCWO. The final GATS design for Blue Grass includes five SCWO reactors (General Atomics, 2001a). The basic SCWO reactor is a retort-style pressure vessel with injectors at the upper end to feed the wastes, air, and a supplementary fuel. Isopropyl alcohol is used as a supplementary fuel during start-up or when needed to maintain the temperature. Early tests of the SCWO reactors (discussed below) indicated significant corrosion and plugging. Plugging problems were solved by procedural modifications that include periodic flushing with clean water at slightly subcritical conditions. The corrosion is mitigated by inserting various composite liners that resist the corrosivity of the different feed streams. The EDS II tests (discussed later in the chapter) showed that titanium backed by Hastealloy C-276 provides adequate corrosion resistance for treating tetrytol hydrolysate, M28 propellant hydrolysate, and slurried dunnage in these two hydrolysates. It also showed that C-276 alloy has sufficient corrosion resistance for treating VX hydrolysate, given the short duration of the VX disposal campaigns at Blue Grass. When treating HD and GB hydrolysate, corrosion was severe for all materials. Thus, the design calls for using an additional sacrificial titanium wear liner that is thick enough to withstand 500 hours of operation (assuming a corrosion rate equal to that measured during the EDS II testing). Although the corrosion rate is high, the liner is designed so that no replacement is necessary during processing of the comparatively small quantities of H in the Blue Grass stockpile. Processing the far greater amounts of GB in the stockpile would require a changeout of the sacrificial titanium wear liner, whose thickness during EDS was sufficient to withstand 120 hours of operation. Therefore, during the GB campaign, the technology provider has scheduled each reactor to be periodically removed from service under a conservative preventive maintenance program that would include replacement of the wear liner and the full-length removable liner after 110 hours. The different liner configurations proposed for use at Blue Grass are shown in Figure 5-2. The first three liner configurations (left to right) shown are the reference designs proposed for the GATS SCWO reactors at Blue Grass on which all of the operations are based. The two rightmost designs are tentative improvements in the liner system. General Atomics proposes to investigate these backup designs if subsequent tests confirm their improved performance, or if they are needed for other reasons. Test results to date on these two “product improvement” designs are noted later in this chapter, but these liner configurations were not considered by the committee as part of its evaluation of the current GATS SCWO system design. Thus, the final design as evaluated consists of a liner system composed of an Inconel 600 insulating barrier over a Hastelloy C-276 removable sleeve. The Hastelloy C-276 sleeve is mounted in the reactor by bolting the flange on the top of the sleeve between the cylindrical body of the reactor and the reactor head. Water-cooled seals are used in this joint. A full-length, cylindrical removable liner is inserted into the Hastelloy C-276 sleeve assembly. The two are separated by spacers, which also hold the removable liner in place while allowing some differential expansion and contraction. The liner during the disposal campaigns when tetrytol and M28 propellant hydrolysates and slurried dunnage are treated is a commercially available titanium pipe. When processing VX hydrolysate, the liner is made of Hastelloy C-276 pipe. When processing HD and GB hydrolysates, a titanium pipe is inserted as an additional sacrificial wear liner into the

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot FIGURE 5-2 GATS SCWO liner materials and configuration. SOURCE: General Atomics (2001a). full-length titanium liner at the top portion of the reactor, where the corrosion has been found to be the worst. In summary, all of the GATS composite liner systems consist of three major components: (1) an Inconel 600 insulating barrier, (2) a Hastelloy C-276 outer sleeve liner, and (3) a full-length, removable liner made of titanium or Hastelloy C-276. In addition, for HD and GB hydrolysates, a short-wear liner is inserted into the removable liner. The GATS design calls for five SCWO reactors. Three of the SCWO units are dedicated to processing the energetics hydrolysate slurry and two to processing agent hydrolysate. The three SCWO units for processing energetics hydrolysate slurry have titanium liners that are expected to last for the duration of operations at a Blue Grass facility. The two agent hydrolysate SCWO units have liner types and change-out frequencies appropriate for the specific agent. With two SCWO units used for agent hydrolysate, one unit is always available as a spare. Table 5-4 gives the specifications for the SCWO reactors. The reactors operate at approximately 650°C (1,200°F) and 3,400 psig. These conditions are well above the critical temperature and pressure of water. The oxidizer is either pressurized ambient air or a synthetic air consisting of a mixture of oxygen and nitrogen at a 21:79 volume ratio, delivered at a feed rate that is 20 percent in excess of the stoichiometric requirement.2 Isopropyl alcohol and water are used to adjust the waste feed to the proper heating value. The isopropyl alcohol is added as an auxiliary fuel whenever needed to maintain an autogenous3 feed mixture to the SCWO reactor. During system start-up, an electric preheater and the isopropyl alcohol feed are used to heat the reactor to the desired operating temperature. When the reactor is at operating temperature, the preheater is turned off, hydrolysate flow is initiated, and auxiliary fuel and water flows are adjusted to control the temperature at the set point. The fluid discharged from the SCWO reactor passes through a water-cooled heat exchanger and staged-pressure gas-liquid separation equipment. Noncondensable gases, mostly nitrogen, carbon dioxide, and the excess oxygen, are monitored and filtered before release to the environment via the plant HVAC HEPA filter and activated carbon adsorption system. Liquids are monitored and transferred to the brine recovery area. If fluid does not meet release specifications, it is returned to a storage tank for off-specification product and reprocessed in the SCWO reactors. 2   The equipment that will be used had not been specified at the time this report was prepared. 3   Autogenous means that the heat released from the oxidation reaction is sufficient to maintain the reactor temperature so that no external heat is needed to maintain the process temperature.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot TABLE 5-4 SCWO System Design Parameters Equipment Component Requirement (Normal Operating Conditions) Reactor 18.4-in. I.D. × 221 in. long (process dimensions) 3.25-in. thick vessel (1 1/4 Cr, 1/2 Mo) steel Removable liner, outer support sleeve ¼4-in. C-276 Removable liner, full length, inner corrosion-resistant sleeve ¼4-in. C-276 Removable liner assembly in upper reactor zone Multiple liner options depending on feed Process oxidant Air Water feed pump (to preheater) 6 gpm, 3,800 psi Hydrolysate feed pump 15 gpm, 3,800 psi Quench pump 32 gpm, 3,800 psi Auxiliary feed pump 3 gpm, 3,800 psi High-pressure oxygen system 3,100 lb/hr (for synthetic air) High-pressure nitrogen system 12,800 lb/hr (for liner purge and synthetic air) Hydrolysate tank 10-hr holdup, 25% free space, 12,000 gal Water tank 4-hr holdup, 25% free space, 2,400 gal Auxiliary fuel 750-gal tank Transfer pumps 4 pumps Start-up preheater 600 kW steam generator, 1,000°F, 3,800 psi Cooldown heat exchanger 22 million Btu/hr, U-tube heat exchanger Gas pressure letdown Redundant control valves and pressure regulators Liquid pressure letdown Redundant capillaries and control valves NOTE: Two SCWO units are for processing energetics hydrolysate (slurried with dunnage), two SCWO units are for processing agent hydrolysate, and one SCWO is available for either service; five interchangeable trains total. SOURCE: Adapted from General Atomics (2001a). As previously noted, the three-component basic liner is fitted into the SCWO reactor pressure vessel by bolting the flange of the Hastelloy C-276 sleeve liner (the horizontal component in Figure 5-2) between the SCWO reactor pressure vessel and the reactor head. A small flow of nitrogen gas is maintained in the gap between the liner and the pressure vessel. The nitrogen flow insulates the reactor wall, keeps corrosive fluids from touching the reactor wall, and prevents binding of the liner assembly to facilitate its removal. With this design, the liner can be periodically replaced to compensate for corrosion, and the pressure vessel can be fabricated from low-alloy steel with a relatively thin corrosion-resistant coating. Treatment of Metal Parts In Step 13, solids from the ERH pass through a chute to an HDC; in Step 16, metal parts from the PRH pass through another chute to a similar but different HDC. The HDCs are electrically heated and purged with nitrogen. The materials in each HDC are heated to 1,000°F (538°C) and held at temperature for at least 15 minutes. The conditions are sufficient to decontaminate the solids to a 5X level or to cause residual energetic materials that might remain in the solids to decompose. The solids leaving the HDCs are cooled and disposed of off-site. Offgases from the HDCs in Steps 13 and 16 are passed through the respective gas treatment systems of the ERH or PRH before being discharged to the plant ventilation system. Water Recovery and Salt Disposal In Step 14, the brine from the four SCWO reactors is concentrated using evaporation/crystallization equipment to reclaim the water and generate solid salt cake for off-site disposal. The evaporation/crystallization step has been eliminated from the designs for the bulk agent disposal facilities at the Newport, Indiana, and Aberdeen, Maryland, sites, and brine from the baseline system facility at Tooele, Utah, is being sent off-site rather than processed in the facility’s brine reduction area. It is the committee’s understanding that the off-site disposal of SCWO liquid effluent and the elimination of this step is being investigated for Blue Grass as well.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot The brine recovery system (BRS) receives the effluents from the SCWO units processing agent hydrolysate and energetics hydrolysate slurry and separates the water for recycle from the salts for disposal. The BRS consists of a reverse osmosis system, a regenerative heat exchanger, a brine concentrator, a crystallizer, and solids separators. The BRS converts the SCWO effluent, which is approximately 2 to 4 weight percent salt solution (primarily sodium sulfate, sodium fluoride, sodium chloride, and sodium monophosphate), to a salt cake and a high-purity water that is recycled into the process as needed. Unneeded water is discharged. Decontamination of Aluminum Precipitate In Step 15, the precipitated aluminum salts produced in Step 7 are decontaminated. This step is necessary to ensure that the precipitate meets 5X decontamination requirements before being sent off-site for disposal. The 5X decontamination is to be done in a dedicated electrically heated screw conveyor. Design and Throughput Basis for the GATS The GATS process is designed to process the stockpile of chemical munitions stored at Blue Grass Army Depot (shown in Table 1-3). It treats the entire assembled munition, including agent, energetics, munition casing, and associated packaging and processing waste materials. The quantities of these materials in need of processing are listed in Table 5-5. The GATS process is designed to coprocess projectiles and rockets containing the same type of agent to minimize processing time. Three campaigns are planned: one for coprocessing GB projectiles and GB rockets, one for coprocessing VX projectiles and VX rockets, and one for HD projectiles alone. Five sets of mass and energy balances have been produced: (1) GB projectiles and rockets coprocessing, (2) GB rockets alone (after all GB projectiles are gone), (3) VX projectiles and rockets coprocessing, (4) VX rockets alone (after all VX projectiles are gone), and (5) HD projectiles alone. Processing rates have been selected, as shown in Table 5-6. The duration of the processing campaigns for munitions disposal is set by the processing rates of the two RSMs and the one PMD machine, with the other processing equipment sized to match these rates. The RSMs are operated during the GB and VX rocket campaigns. The PMD machine extracts bursters during pro TABLE 5-5 Waste Materials to Be Processed per Munition Material Amount Wood 4.33 lb per rocket 8.55 lb per 8-in. projectile 12.67 lb per 155-mm projectile Decontamination solution 5 lb per round DPE suits 0.15 lb per round Carbon 0.3 lb per round Waste oil 0.3 lb per round Miscellaneous metal 0.4 lb per round Hydraulic fluid 0.4 lb per round   SOURCE: Adapted from General Atomics (2001c). cessing of HD projectiles only. It acts only as a conveyor during the GB and VX campaigns, with no operation on the projectiles. The RSM operating rate is 10 rockets per hour per machine, a 6-minute cycle during which one rocket is brought into the ECR, punched and drained, and flushed. During the same 6 minutes, a second rocket is moved from the punch-drain-flush station to the RSM, is sheared into nine segments, and then is transferred to the ERH. This processing rate is well within the demonstrated processing rate for the RSM in the baseline incineration system. Experience at Johnston Atoll Chemical Agent Disposal System (JACADS) with the RSM shows typical rates of 18 to 22 rockets per hour per RSM (without flushing). The maximum operating rate of the PMD machine is specified at 50 projectiles per hour. This rate is used only for the 310 processing hours scheduled for 155-mm HD projectiles. In the 72-second cycle, the PMD machine loads one projectile on the rotating table, while in the same period removing the nose closure from a second projectile, the fuze well cup and burster from a third, and unloading a fourth projectile from the table to the projectile agent removal system. Experience with the PMD machine at the Johnston Atoll baseline system facility shows that the theoretical maximum operating rate of 144 projectiles per hour has never been achieved. Maximum rates of 48 rounds per hour were used for 155-mm HD and 155-mm VX processing. Two-thirds of the rounds were processed at rates exceeding 30 rounds per hour, and more than one third at rates exceeding 40 rounds per hour. Lessons learned during baseline system operations at Johnston Atoll are expected to improve the rate and availability of the PMD machine.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot TABLE 5-6 Munition Processing Rates and Durations Munition Name Number (rounds) Processing Rate (rounds/hour) Processing Time (hours) Processing Days (at 12 hours/day) M55 GB rocket 51,417 20 2,571 214 8-inch GB projectile 3,977 10 398 Coprocessed with GB rockets M55 VX rocket 17,733 20 886 74 155 mm VX projectile 12,816 20 641 Coprocessed with GB rockets 155 mm HD projectile 15,492 50 310 26 Total 101,435     314   SOURCE: Adapted from General Atomics (2001a). A GATS facility for Blue Grass would operate 24 hours per day, 46 weeks per year. According to the General Atomics EDP, the equipment for munitions processing, energetics and agent extraction, and hydrolysis is assumed to operate productively 72 hours per week (averaging 12 hours per day, 6 days per week). SCWO equipment is assumed to operate productively 132 hours per week (averaging 22 hours per day, 6 days per week), but with only 50 percent utilization (i.e., 100 percent spare capacity is provided). The GATS process design is sized on the assumption that a Blue Grass facility overall will only be operating productively 38 percent of the time, i.e., 38 percent availability. The requirement for 38 percent online availability means an offline allowance of 62 percent of the time, which can be used for equipment maintenance and repairs. The required capacity factor of 38 percent sets a very low reliability requirement for the equipment and provides a margin for combined equipment failure rates within a processing line. With the selected RSM and PMD machine rates, all equipment and processes are sized to achieve the required average weekly output of 3,600 155-mm H projectiles, 1,440 155-mm VX projectiles, 720 8-inch GB projectiles, or 1,440 rockets (VX or GB) per week. If the actual average operating hours achieved during the munition processing campaigns exceed 72 hours per week, the plant would complete operations ahead of schedule. The GATS process components are sized so that all material processing can be balanced on a weekly basis. For example, all agent hydrolysate and energetics/dunnage hydrolysate produced during a given time period would be completely processed by SCWO during a similar time period. Buffer storage at the front end of each process is sized to prevent minor upsets in flow from affecting total throughput. The ERH and PRH operate on a cycle that follows the operation of the RSMs and PMD machine or cryofracture steps. Hydrolysate and decontaminated metal parts emerge from the projectile agent removal system and ERH steps after the design residence time—from 2 to 6 hours. Hydrolysate is collected in buffer storage tanks so that the SCWO operations can be independent of the other parts of the process. The 16 unit operations shown in Figure 5-1 are evaluated by the committee in subsequent sections of this chapter. For clarity, some secondary unit operations (such as CATOX units) are not shown in Figure 5-1. The GATS design anticipates the movement of munitions from storage to the MDB using modified ammunition vans (MAVs). Transport will be in two steps: first to the container handling building (CHB), and then to the unpack area (UPA) in the MDB. INFORMATION USED IN DEVELOPING THE ASSESSMENT Engineering-Design-Related Documents In December 2001, General Atomics issued a final draft of the EDP for a full-scale pilot plant implementing its technology package at Blue Grass Army Depot (General Atomic, 2001a). The EDP includes technical descriptions and data, drawings, a preliminary hazard analysis, and cost and schedule analyses. The committee used it as the primary source of information for this assessment. Other EDP-related documents used in the assessment include the initial draft of the EDP and the study plan and test reports for the EDS submitted by General Atomics (with addendum) (General Atomics,

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot Treatment of Hydrolysates and Dunnage by Supercritical Water Oxidation (Steps 11, 12, and 14) Step 11 is treatment by SCWO of the energetics hydrolysate mixed with hydropulped dunnage. Step 12 of the GATS process is treatment of the agent hydrolysate from the continuously stirred reactors by SCWO. The two steps are evaluated collectively. The Blue Grass design incorporates changes based on over 4,900 hours of testing with waste and nearly 5,800 “hot hours” (either waste or only fuel) of operation of SCWO systems similar to that proposed for Blue Grass. Table 5-7 lists the major test campaigns for the GATS SCWO system that were conducted in support of this design and that were considered by the committee. This time of operation may be compared to the 16 months of operation encompassing a total of 11,311 SCWO reactor hours estimated to be necessary at Blue Grass (General Atomics, 2001a). As previously noted, the Demo I and EST tests showed that SCWO was an effective method for destroying the organic materials found in the agent and energetics hydrolysates and in the dunnage at Blue Grass, but that the SCWO reactor was subject to two basic problems: effective transport of solids and identification of suitable materials of construction. The solids transport problem is caused by the use of sodium hydroxide for neutralization of agent and the presence of chlorine, sulfur, fluorine, or phosphorus in the agents. These materials lead to the formation of various inorganic compounds that must be flushed out of the SCWO system periodically. These inorganic compounds generally dissolve in liquid water (at subcritical conditions) but precipitate under the supercritical conditions of the SCWO reactor.5 The behavior of the precipitates is complicated because some melt at SCWO conditions and others remain solid. Based on the test results, the committee concluded that periodic flushing of the system and other operating procedures that General Atomics developed during the testing should prevent accumulation of solids and plugging of the reactor during operation. However, the committee is still concerned that such a system has never been tested at larger scale. The corrosion of the reactor walls (as exemplified in Table 5-8) further complicates the solids problem because the products of corrosion include metal salts or oxides that are insoluble in both subcritical and supercritical water. Also, the warheads of rockets, the end caps from shipping tubes, and other munition parts are made of aluminum, which forms a hydroxide in the caustic and exacerbates the solids handling problems. General Atomics has developed proprietary additives and routine flushing procedures that successfully manage the solids transport problems. Unfortunately, one of the additives increased the corrosion rate, especially that of titanium. Based on the new information from the tests listed in Table 5-7, the committee reassessed the SCWO system’s performance and operability. Ultrasonic testing after the tetrytol hydrolysate-dunnage and M28 hydrolysate-dunnage tests showed that the full-length titanium liner (leftmost liner of Figure 5-2) had excellent liner life with no visible or measurable degradation of the liner (<3 mils) after the extended-duration tests of these materials. The SCWO treatment of the micronized dunnage (with metal removed) slurried with energetics hydrolysate was of concern to the committee until it received the EDS test reports. The EDS tests showed that the SCWO system can successfully process slurries of organic materials, even if they contain small quantities of tramp metal. The SCWO testing of energetic hydrolysate slurried with shredded and micronized dunnage was successfully demonstrated. No liner changes appear to be necessary for the treatment of the energetics hydrolysate-dunnage slurry during the full SCWO campaign. As discussed below, corrosion remains a problem with hydrolysates of mustard agent, GB, and VX. However, because the duration of both the VX and H disposal campaigns is short, no liner changes will be required. Only the SCWO treatment of GB will require liner change-outs. For the titanium liner configuration (i.e., the middle configuration in Figure 5-2), the two SCWO reactors treating GB hydrolysate will each require six liner changeouts. A Pt/Ti hybrid liner (the rightmost configuration in Figure 5-2) promises to reduce the number of change-outs to one per reactor during the GB disposal campaign. The problem in the treatment of the two organophosphorus agents appears to be associated with the phosphorus they contain. The phosphorus present as a phosphate in the reactor appears to attack the protective TiO2 film that coats the titanium metal. Once this film is removed, the exposed Ti metal is attacked by water and oxygen. Oxygen forms more TiO2, which in turn is 5   Some of these salts would dissolve under “high pressure” supercritical conditions, but these conditions require pressures that are substantially above those of the SCWO reactors of the GATS design.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot TABLE 5-8 Corrosion of Titanium Liners During GATS EDS Workup Tests with HD Hydrolysate Date Event Fuel Hours Feed Hours Total Hot Hours 10/4/00 Start Ti rolled-sheet liner #1 (Grade 7, 0.030 in. thick). 0 0 0 10/5/00 Small hole in liner about 2 in. below nozzle tip. Two patches each several inches square with wall thinning of about 10 mils. 10 23 33 11/1/00 Start Ti rolled-sheet liner #2 (Grade 7, 0.030 in. thick). 0 0 0 11/2/00 Ti pit depth ~10 mil. General thickness loss <~1 mil. 6 33 39 11/12/00 ~2,000 small pits counted with maximum depth ~10 mil. Switch to new liner for 5% HD hydrolysate simulant tests. 16 145 161 11/14/00 Start repaired Ti rolled-sheet liner #1. 10 23 33 11/17/00 Switch to testing of Grade 2 pipe liners. 17 85 102 11/18/00 Start Ti pipe liner #1 (Grade 2, 0.110 in. thick). 0 0 0 11/19/00 Pitting noted 16 in. below nozzle tip. Maximum depth ~10 mil. 2 20 22 11/22/00 Pitting from 6 to 18 in. below nozzle tip. Maximum depth ~20 mil. Maximum general corrosion ~5 mil. 7 47 54 11/30/00 Maximum general corrosion ~50 mil, primarily in top 3.5 in. below the nozzle tip. Maximum pit depth ~20 mil. 10 105 115 12/1/00 Start inverted Ti pipe liner #1 (Grade 2, 0.110 in. thick). 10 105 115 12/5/00 Maximum corrosion ~85 mil, a bit less than 1 mil/hr. Corrosion primarily in top 3.5 in. below the nozzle tip. 21 200 221 12/12/00 Ti pipe liner #1 returned to original orientation. 27 237 264 12/17/00 Ti pipe liner #1 broken during removal from Hastelloy sleeve. 38 294 332   SOURCE: Adapted from General Atomics (2001a). attacked by phosphate. Water forms both TiO2 and TiH2. In fact the most depleted part of the corroded liner was found to have been completely converted to titanium hydride (General Atomics, 2001a). The titanium hydride does not appear to cause any problems. It seems to hold up well, and the 20 percent swelling caused by the hydride formation seems to lock the titanium into place. According to General Atomics, the rate of phosphorus attack is reasonably linear (General Atomics, 2001f). Thus, a thicker liner will have a longer life. For example, the values for liner life (shown by hours per reactor) in Table 5-9 are computed by assuming that a thicker (0.5-inch-thick) liner will be destroyed at the same rate as was the thinner liner during the tests. The committee believes that this assumption is reasonable in the absence of firm data; however, the assumption does introduce a level of uncertainty about the actual life of the liners for the disposal campaigns for GB munitions at Blue Grass. Because there are relatively few VX munitions at Blue Grass, total operation with VX hydrolysate shown in Table 5-9 is projected to be only 216 hours split between two reactors, i.e., 108 hours per reactor. Even under the worst corrosion conditions, the VX hydrolysate disposal campaign will take less time than the liner lifetime experienced (with the much thinner liner) during EDS testing. The GB disposal campaign will require 1,522 reactor hours split between two reactors. This will require six liner changes per reactor, or twelve liner changes over the total 16-month operating life of the plant. The number of reactor liner changes shown in Table 5-9 assumes that each reactor’s life is only 761 hours, divided by seven liners, or about 110 hours. In the opinion of the committee, this still constitutes a very large amount of maintenance This liner life, which is used by General Atomics as the basis for its design, is shorter than the 120-hour projected liner life that was based on the EDS test results. This shorter projected life and the extra SCWO reactor provide additional margins of safety in the overall design. The General Atomics EDP for Blue Grass addressed the uncertainty surrounding SCWO liner life in two ways. First, the EDP design includes an extra SCWO system that can be put online if the number of liner changes is larger or the time required to perform liner changes longer than anticipated. Second, extra time has been built into the operating schedule to compensate for the uncertainties. The 500-hour tests were conducted on a SCWO reactor with an internal diameter of approximately 4 inches. The full-scale system will have an internal

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot TABLE 5-9 Liner Lifetime and Replacement Calculations for Blue Grass Facility SCWO Reactors Feed Liner Material Total Time in Reactor (hr) No. of Reactors Time per Reactor (hr) Maximum Corrosion Rate Mils Corroded No. of Liner Change-outsa GB hydrolysate Ti/Ti 1,522 2 761 2.5 mil/hr 1,903 6 (per reactor) GB hydrolysate improvementb Pt/Ti 1,522 2 761 <0.5 mil/hr (for Ti) 380 1 (per reactor) Energetics from GB munitions/dunnage Ti 6,943 3 2,164 <1 mil/100 hr 22 0 VX hydrolysate C-276 216 2 108 0.4 mil/hr 43 0 Energetics from VX munitions/dunnage Ti 2,399 3 800 <1 mil/100 hr 8 0 H Ti/Ti 229 2 115 0.5 mil/hr 58 0 Energetics from H munitions/dunnage Ti 116 3 39 <1 mil/100 hr 0 0 aBlue Grass liner change-outs—all titanium and C-276 liners 0.5-in. initial wall thickness, change-out when 0.2 in. remaining. bPlatinum (0.030-in. thick) wear liner has shown good performance after 128 hr of testing with GB and VX hydrolysate simulants. Pt corrosion is negligible and Ti corrosion rate is reduced to <0.5 mil/hr, resulting in one Ti liner change per reactor with GB hydrolysate at Blue Grass. SOURCE: Adapted from General Atomics (2001a). diameter of approximately 18 inches and will be 18 feet long. Because this is a substantial increase in size, the impact on the corrosion rate, plugging by precipitates and other solids, and other performance factors cannot be reliably assessed until the scaled-up SCWO unit is operated. In conclusion, the next step in the application of a SCWO system at Blue Grass is the actual construction and testing of one full-scale unit under actual conditions. In the committee’s opinion, the information that additional testing on a smaller scale would provide would only be of marginal value for the construction and operation of the full-scale system. Water Recovery and Salt Disposal In Step 14 of the GATS process, the brine from the SCWO reactors is concentrated for water recovery and generating a solid salt cake for off-site disposal. Although the EDP did not include specific design parameters for this unit operation, it is existing technology, and assuming that the SCWO reactor produces an effluent with the very low organic content called for in design specifications, appropriate concentration/crystallization equipment is commercially available. The committee notes that other chemical weapons demilitarization facilities have eliminated this processing step and suggests that similar changes be evaluated for the Blue Grass facility. ASSESSMENT OF INTEGRATION ISSUES The issues surrounding integration of General Atomics’ technology package at the current stage of design were addressed in the ACW II Committee’s earlier report for EDS I, which addressed ACWA technology options for disposal of the Pueblo stockpile (NRC, 2001a). The committee’s analysis is equally applicable to a GATS facility at Blue Grass and is presented again below with some updating and adaptation for Blue Grass. Component Integration Destruction of the Blue Grass stockpile in time to meet the CWC treaty deadline will require that the availability and throughput of each processing step, along with redundant process trains and sufficient buffer storage capacity between individual processing steps as necessary, result in the specified destruction rate. General Atomics has conducted a detailed throughput analysis that takes into account intermediate storage capacity. On the basis of this analysis, General Atomics has verified that planned throughput rates can be achieved. Proper training of plant operating and maintenance personnel is important, because their effectiveness contributes to process availability. General Atomics has designed the GATS process and sized the equipment to process the Blue Grass

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot stockpile in 16 months (General Atomics, 2001a). The output rate from the reverse-assembly PMD system determines the size and number of units for all downstream process equipment. Because the GATS PMD equipment is similar to the equipment used in the baseline incineration system, the operating experience from baseline facilities led General Atomics to conclude that a throughput rate of 50 rounds per hour per machine would be attainable. General Atomics has estimated that the long-term average capacity for the GATS design for Blue Grass (actual throughput per year/maximum theoretical throughput per year) is 38 percent. To meet this availability, two PMD machines are required to handle the Blue Grass stockpile. The size and number of the rest of the General Atomics process equipment is designed to match the throughput of the PMD operation. For example, two SCWO reactors are used to treat the downstream agent hydrolysate, and two more SCWO units are used to treat the micronized dunnage and energetics hydrolysate waste stream. Integrating the individual processing steps requires effective process monitoring and control to ensure that appropriate materials are fed to each processing step and that all materials discharged from the plant meet all safety and environmental specifications. Monitoring and control of the integrated facility will be based primarily on the methods used in the baseline system. The overall monitoring and control system consists of the basic process control system (BPCS), the emergency shutdown system (ESS), and PLCs (programmable logic controllers) for individual equipment units. The BPCS is composed of microprocessor-based controllers for monitoring and control. The ESS is a dedicated safety system of PLCs or microprocessor-based controllers that provide protective logic and shutdown capability. The means of controlling machines throughout a GATS facility are similar to those used for the baseline system machines (i.e., sequence-enabled functions with position switches). Most of the monitoring instruments specified in the GATS design package are simple and reliable, having been used extensively in the chemical industry. Control valves and monitors for temperature and pressure, as well as distributed control systems and PLCs, have also been widely used in industry. Process Operability The operability of the SCWO reactors remains a significant issue. The reactors’ operating conditions are set to balance competing conditions for minimizing plugging by salts and minimizing liner corrosion. That is, the conditions for good salt transport (and hence minimal plugging) are also the conditions that cause maximum corrosion. Conversely, operating conditions with minimum corrosion are conducive to the precipitation of salts, which can cause plugging. General Atomics has approached this problem by (1) the use of a proprietary additive to improve salt transport and (2) designing the SCWO reactors with a removable sacrificial liner that would be replaced at regularly scheduled intervals. This combination, along with careful monitoring and control of temperature, pressure, additive feed rates, and other operating conditions, reduces the severity of the salt plugging and corrosion problems, but not sufficiently. The committee believes the SCWO system will still be very difficult to operate, especially at full scale (see also the section on maintenance issues, below). Monitoring and Control Strategy As discussed in previous NRC reports, except for the monitoring of corrosion and salt plugging, discussed above, the GATS process does not require any unusual monitoring or control systems (NRC, 1999, 2000a). The process control strategies consist of straightforward monitoring of pressure, flow rate, and temperature by well-established methods and equipment. General Atomics believes that monitoring the turbidity resulting from suspended titanium dioxide in the reactor effluent will effectively monitor corrosion rates. Monitoring the turbidity of the effluent gives a good indication of the instantaneous corrosion rate, which can be used to ensure that operating conditions remain within the desired range. However, the decision to shut the process down for liner replacement would be facilitated if the extent of corrosion could also be monitored. This could be done by adapting one of various probe designs available commercially or developed in previous SCWO studies (Macdonald and Kriksunov, 2001). Another simple method would be to measure the electrical conductivity of the thermocouple well. Maintenance Issues The EDS testing clearly showed that successful operation of the SCWO system requires an aggressive,

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot proactive maintenance program to replace (1) the thermocouple well and (2) the titanium liner after every 120 hours or so of operation. Replacement of internal components of the SCWO reactor is a time-consuming, elaborate procedure that involves cooling the system, flushing with clean water, manually removing the pressure head from the reactor, manually removing the liner, inverting the liner or replacing it with a new liner, reassembling the reactor, and restarting the system. General Atomics has performed this procedure more than 100 times on reactors with test-size (3- to 4-inch ID) liners during the EDS and other SCWO test programs (Hong, 2001). During the EDS tests, the shutdown/start-up procedure required an average of 7 hours (3 to 11 hours) to complete. However, maintenance has been performed only on comparatively small test-size SCWO reactors. The SCWO reactors proposed for the Blue Grass facility are approximately 18 inches in diameter and 18 feet long. Thus, the length of the liner to be removed is considerably greater than the length of liners removed to date. The head at the top of an 18-inch reactor will not only be larger, but it will also have to be considerably thicker to withstand more than 20 times the force from internal pressure. Thus, the head on the full-scale reactor will be heavier and bulkier and will have more and larger bolts to be removed and replaced than the small SCWO test reactors. It will also have a larger sealing surface that will have to be set and pressure tested. In the committee’s experience, proper pressure sealing of equipment is very time consuming. Consequently, the time and effort required to change the liner are likely to be much greater than those required in the EDS and Demo I tests. Process Safety The ACW I Committee concluded in its original report that there were “no unusual or intractable process safety problems” associated with the GATS process (NRC, 1999). However, in a subsequent evaluation of the Demo I test results, some aspects of process design for which safety needs to be addressed were identified (NRC, 2000a). General Atomics also acknowledged these safety design requirements in its report on the Demo I test results (General Atomics, 1999a): Modify the design to incorporate equipment for removing precipitated aluminum compounds to minimize aluminum-caused salt plugging and associated maintenance. (For Blue Grass, aluminum removal requirements are minimal because the only aluminum in the munitions is expected to be in fuze assemblies.) Control volatile organic vapors generated in the ERH to prevent the accumulation of explosive mixtures in the ERH offgas system and to minimize the maintenance requirements for removing condensed organics from fugitive emissions entering the ERH explosion containment cubicle. Incorporate safety features to preclude dust explosions in the DSHS. All of these concerns have been addressed in the EDS design package to the extent possible at this design stage (General Atomics, 2001a). During the information-gathering phase of this report, the committee learned of an occurrence on December 2, 2000, involving backflow of fuel into the liquid oxygen feed line for the General Atomics SCWO reactor being tested in Corpus Christi, Texas, for treatment of VX hydrolysate at the Newport site (PMACWA, 2000). This backflow caused an overpressure (possibly in excess of 5,000 psig) and permanent expansion of part of the liquid oxygen feed line. The overpressure is believed to have come from the oxidation of fuel in the oxygen line. An earlier occurrence (July 14, 2000) involving the oxygen feed line caused a release of oxygen through the relief valve, which caused a grass fire from melting metal components of the relief valve.6 The fire was attributed to removal of the high-pressure and high-high-pressure shutdowns from the pump circuit control and the use of stainless steel rather than Monel metal for the pressure relief valve. Based on these incidents, the committee inferred that the General Atomics SCWO system would continue to be vulnerable to fires if pure oxygen and nitrogen were used to produce synthetic air for the SCWO reactors. The committee notes that the final preliminary hazards analysis (PHA) in the EDP for Blue Grass recommends redundant oxygen sensors to protect against high oxygen levels in the synthetic air mixture (General Atomics, 2001a). Use of compressed air, however, would completely eliminate this hazard, and General Atomics notes in its summary of the PHA that it may consider using compressed air to reduce costs. 6   Bernard Bindel, safety engineer, PMCD, personal communication on March 26, 2001.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot As a part of the EDS design package, General Atomics prepared a PHA in accordance with MIL-STD-882C (DoD, 2000). The committee’s review of the final PHA and the Hazard Tracking Recommendations and Resolution (HTRR) log, indicates that the PHA and the HTRR make good use of engineering changes to reduce risk and rely primarily on procedural or administrative controls where the actions of operator and maintenance personnel are a threat. The PHA considered hazards in three categories: agent release, personnel injury, and system damage. This multiattribute approach provides increased assurance of achieving safety goals for preventing agent release and protecting personnel because it also suggests ways to make the system operate more reliably, thereby requiring less repair and maintenance. The final EDP PHA for Blue Grass confirms some committee concerns and recommends measures to address them. For example, a cover is recommended for the cryobath, with venting of vapors through a CATOX system when evaporating liquid nitrogen for purposes of bath cleaning and repair. Similarly, recommendations in the PHA include added instrumentation and equipment redundancy to reduce the chance that hydrogen gas will accumulate in the ERH and its vent gas. The PHA appears to have been conducted in a satisfactory manner at this stage of design. Of course, it will have to be updated as the GATS design progresses to completion for use in construction. Worker Health and Safety The conclusions regarding worker health and safety in the ACW I Committee’s original and supplemental reports are still valid (NRC, 1999, 2000a). The primary hazardous materials used during the destruction of agent and energetics are sodium hydroxide, liquid and gaseous oxygen, liquid and gaseous nitrogen, and methane (natural gas) for boiler fuel. Sodium hydroxide will be delivered in concentrated liquid form (50 weight percent) and diluted with water to produce the required weaker solutions. This corrosive caustic is handled safely in similar quantities and concentrations throughout the chemical industry and should not be unusually hazardous in the GATS process. Liquid and gaseous oxygen, liquid and gaseous nitrogen, and methane are also handled routinely and safely in many industries and do not present an unusual hazard to workers. The committee’s review of the PHA reveals extensive recommendations for assuring worker safety. This result supports the committee’s earlier conclusion that an adequate level of worker safety would be provided for in the design and the procedures that would be used for facility construction and operation. Public Safety Accidental releases of agent or other regulated substances to the atmosphere or the groundwater system are extremely unlikely. Caustic scrubbing and activated carbon filtration are used on all gaseous process streams. Based on experience with the baseline facilities, these measures should provide a reasonable level of safety. Hold-test-release systems are not provided for gaseous effluents, but the scrubbing and filtration scheme, combined with the standard automatic continuous air monitoring system (ACAMS) monitors used at baseline facilities, should provide adequate protection for all gaseous process effluents. The facility HVAC design is similar to the design at existing baseline facilities, where air flows from clean areas to potentially contaminated areas and then through high-efficiency particulate air (HEPA) and activated carbon filters before release to the atmosphere. The primary cause of a release of agent or other regulated substances would be the explosion of a munition or the rupture of a pipe or vessel, but the likelihood of such events should be extremely small. This conclusion is based on the committee’s review of the General Atomics EDP for Blue Grass and the understanding that the PMCD will require a comprehensive quantitative risk assessment (QRA) for the final facility design to ensure acceptable levels of risk. A QRA, which is much more detailed than the PHA performed at this stage of design, is a risk management tool during actual operation of the facility and forms a basis for evaluating proposed changes in design or operation in accordance with Chemical Stockpile Disposal Program (CSDP) risk-management policies and procedures (PMCD, 1996, 1997). QRAs are typically developed in parallel with the completion of the facility design and construction. However, because design-based solutions to high-risk hazards can be implemented more easily during the design stage than during the construction stage, early implementation of the QRA process can be advantageous. The later in the design that a QRA is prepared, the greater the tendency to rely on procedural and administrative solutions, which often complicate operations and are less effective than design modifications.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot TABLE 5-10 500-hr Test Effluent Quality   HD TD MD GB VX (200 hr) TOC (liquid) (ppm) ≤1.3 <1 ≤1.9 <2.6 <1 TCLP metals (liquid) (ppm) Meets criteria except for 5 ppm Cr in feed Meets criteria Meets criteria Cr = 0.7, Ti = 0.6 (?) Ni = 50, Cr = 13 CO (gas) (ppm) <10 <10 <10 <10 <10 NOx/ SOx (gas) (ppm) <1/<1 <1/<1 <1/<1 5.2/0.2 Not analyzed Dioxins/furans 200 times below EPA MACT standard Not analyzed 72 times below EPA MACT standard Not analyzed Not analyzed NOTE: HD, HD hydrolysate; TD, tetrytol hydrolysate slurried with shredded and micronized dunnage (palettes, DPE suits, gloves, etc.); MD, M-28 rocket propellant and burster hydrolysates slurried with shredded and micronized dunnage that has had the hydrolyzed aluminum removed by filtration; GB, GB hydrolysate; VX, VX hydrolysate. SOURCE: Adapted from General Atomics (2001a). Human Health and the Environment The environmental impact of the proposed GATS process appears to be minimal. All handling and processing of agent will be conducted indoors in sealed rooms that are vented through HEPA and carbon filters. Liquid and solid waste streams will be relatively small and manageable and will be subjected to hold-test-release procedures. Effluent Characterization The liquid effluent, which consists of water from the evaporator/crystallizer used to produce the solid filter cake produced by the brine-recovery operation, should not pose a significant hazard to human health or to the environment. While the evaporator/crystallizer system has not been tested yet, the composition of the water and solid filter cake can be readily determined from an analysis of the SCWO liquid effluent. As shown in Table 5-10, the liquid effluent is essentially free of organics. The source of the chromium and nickel that were found in some of the effluents is generally believed to be corrosion products from the SCWO reactor components. These elevated levels of metals indicate that the solid filter cake will need to be treated (e.g., by stabilization) prior to disposal in a hazardous waste landfill.7 Much of the water recovered from the evaporator/ crystallizer is recycled for use in the process. As also shown in Table 5-10, the gaseous effluents contain very low concentrations of hazardous constituents. Furthermore, the flow rates of the gaseous effluents from the SCWO reactor are very low. Thus, the mass emissions of hazardous air pollutants (concentration times gas flow rate) from the SCWO reactor are extremely low. These emissions are further cleaned by passing them through carbon filters. This combination should ensure that the total impact on health and the environment of the SCWO system is minimal. This must be confirmed through formal testing, including comprehensive, full analytical scans that indicate the quantities of a large number of compounds of environmental concern,8 and by fully developed site-specific health and ecological risk assessments for the process. 7   There is a common misconception that the absence of hazardous constituents in a waste makes it nonhazardous. In fact, any waste that is produced by a hazardous waste treatment process such as this is legally hazardous unless it goes through a lengthy legal “delisting” process. The effluent from the Newport Chemical Weapons Destruction Facility’s SCWO system has been delisted by the Indiana Department of Environmental Management. 8   EPA analyses are done with 8000 Series methods, especially those using gas chromatography/mass spectrometry scans (e.g., methods 8260B, “VOCs by GC/MS,” and 8270C, “Semi-VOCs by GC/MS”).

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot Completeness of Effluent Characterization The liquid and solid effluents are well characterized. As the ACW I Committee noted in its original and supplemental reports, the gaseous process emissions will have to be characterized for health risk assessments and environmental risk assessments required by EPA guidelines (NRC, 1999, 2000a). These results, along with the results of analyses of metals emissions (including chromium VI), can be used to assess the environmental impact of a facility through accepted risk-assessment methods (EPA, 1998). Effluent Management Strategy The proposed strategy appears to be reasonable and should protect public health and the environment. Off-site Disposal Options Dunnage. Experience at the baseline system facilities at Johnston Atoll and Tooele, Utah, has shown that only a tiny fraction of dunnage is contaminated with agent. Uncontaminated dunnage from these two stockpile locations is being disposed of off-site by commercial waste management facilities (McCloskey, 1999; U.S. Army, 1998). Off-site management of uncontaminated dunnage is also planned for both the Newport and Aberdeen sites. Off-site management of dunnage from Blue Grass would greatly reduce the on-site processing requirements and greatly simplify process integration by eliminating the need for size reduction and SCWO treatment of the dunnage. Off-site disposal of other agent-free waste streams, such as hydrolysates, may be possible, thereby reducing the number or size of treatment steps. Brines. Brines produced from air pollution control processes at the baseline facility at Tooele, Utah, are currently being shipped off-site for disposal by commercial waste management facilities. Environmental Compliance and Permitting The combination of technologies in the General Atomics technology package is not expected to lead to problems with environmental compliance or permitting. All process waste streams except the SCWO offgas will be evaluated prior to release to confirm that they are either free of regulated substances or that these substances are at acceptable concentrations. The SCWO offgas will be released to the environment via the plant HVAC HEPA and activated carbon filters. The committee considered the small amounts of PCBs that are suspected to be present in rocket motors and concluded that these amounts are far too small to pose an environmental concern. No data on PCBs were provided in any of the tests that the committee evaluated. Any small amounts of PCBs that may be present from rockets treated would end up in one of the solid waste streams and be at a concentration well below regulatory limits. ASSESSMENT OF OVERARCHING TECHNICAL ISSUES Overall Engineering Design Package The EDS test results with the PRH, the ERH, and their HDCs appear to warrant proceeding with these GATS components. The method for treating dunnage and energetics also has been reasonably tested. Corrosion of the SCWO reactor liner and other internal components is high but manageable. All issues about whether the GATS process would be able to destroy the munitions stored at Blue Grass within a reasonable period of time appear to have been resolved. In conclusion, The GATS process meets the whole-plant availability requirement of 38 percent. Readily available, inexpensive titanium grade 2 is a suitable SCWO reactor liner material for TD and MD, and with the addition of a titanium wear liner, as shown in Figure 5-2, it is suitable for processing GB and HD. Readily available Hastelloy C-276 is a suitable SCWO reactor liner material for VX. Improvements have been identified and demonstrated that may afford a lower corrosion rate for SCWO liners and improve effluent quality for all chemical agents, including GB (see the two rightmost liner configurations in Figure 5-2). SCWO system pressure and temperature control are well maintained. Suitable salt transport has been achieved for all feeds to SCWO system reactors; a salt flush is required not more than once a day.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot The SCWO system achieves high organic destruction efficiency. The SCWO system is safe. Steps Required Before Implementation The following additional testing/piloting activities should be carried out in parallel with facility design, construction, and permitting activities: Consider a design change to replace manufactured air (made from liquid oxygen and nitrogen sources) with high-pressure air compressors for the SCWO oxidants. Consider a separate feed conveyor for GB and VX projectiles that do not contain energetics. The conveyor would bypass the PMD area and feed projectiles directly into the projectile agent removal system. Additional Testing/Piloting The following additional testing/piloting activities should be considered in parallel with the facility design, construction, and permitting activities. None of these suggestions are critical to the success of the present operation: Develop an agent sampling and analysis protocol for trace amounts of agent in energetics hydrolysate. Develop a pilot-scale ERH, and demonstrate and verify the materials flow. Develop and test a full-scale SCWO reactor system to verify performance parameters, including preventive maintenance operations. Develop and test other SCWO liners to further reduce liner preventive maintenance requirements. The initial evaluation of the GATS process by the ACW I Committee identified the following steps required for implementation (NRC, 1999). These steps are reevaluated below. Conduct tests of the cryofracture process to ascertain if it provides better access to the agent cavity in projectiles and mortars than the baseline disassembly process. The cryofracture data that were provided resolve this issue. Cryofracture also prevents the effervescent foaming of agent. Sample and analyze air emissions from the demonstration system. The air emissions will have to be measured to a level of detail and accuracy that can be used for HRAS [health risk assessments] and environmental risk assessments required by EPA. Subsequent testing that included extensive analyses of air emissions revealed no obvious concerns. The tests consistently showed extremely low levels of organic contaminants in all SCWO effluents. Final determinations of safety and environmental acceptability can only be made through a formal risk assessment process that will occur as part of the permitting program. Verify that energetic materials encased in metal (e.g., rocket or other munitions fragments) will be hydrolyzed. The EDS testing appears to demonstrate that energetic materials encased in metal can be hydrolyzed successfully, although some questions remain about the completeness of the hydrolysis. During the Demo I testing, fuzes were observed to have “popped” on the HDC, indicating that they may not have been completely hydrolyzed. However, the level of popping appears to have been within the design specifications of the HDC for such events. Ascertain how well the SCWO process can handle high-solids materials (shredded dunnage). SCWO testing was conducted using energetic hydrolysate slurried with shredded and micronized dunnage. The tests showed very low corrosion rates with an inexpensive titanium liner and excellent organic destruction efficiency. The committee concluded that these tests were successful. Determine erosion and corrosion behavior of the components of the SCWO system. The EDS testing and other testing cited in this report has provided design information on the erosion and corrosion of SCWO components. The data, which appear to be reliable, show that corrosion rates are acceptable for the energetics-dunnage slurries, which are the largest streams to be treated at Blue Grass. The results do confirm component corrosion when processing GB, VX, and HD hydrolysate. As discussed earlier under maintenance issues, the corrosion appears to present a significant but not unmanageable maintenance burden for operators and maintenance personnel. Table 5-11 summarizes the status of recent developments concerning the processing of various waste streams by the SCWO reactor.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot TABLE 5-11 Status of Recent Developments on Treatment of Various Waste Streams by SCWO Waste Stream Problem Approach Recent Developments HD hydrolysate Platinum corrosion and mechanical instability Use of a titanium reference liner with extended change-out frequency for a given full-scale reactor every 500 hr or longer Titanium liner showed corrosion rates compatible with 500 hr of operational life. Other test data indicated that a platinum liner (per Configuration 5 in Table 5-2) would be sufficiently corrosion resistant to not need change-out during HD hydrolysate disposal at Blue Grass. GB and VX hydrolysate Titanium corrosion and embrittlement For GB: Extend titanium reference liner change-out frequency using multiple reactors or implement Pt wear liner product improvement For VX: Adopt Hastelloy C-276 reference liner or implement wear liner product improvement Problem is being managed through an aggressive preventive maintenance program. Tetrytol hydrolysate/dunnage slurry Operational difficulties encountered while encountered while processing mixed dunnage containing carbon Processing the carbon separately with internal baffles in SCWO reactor to ensures sufficient residence time; alternatively, decontaminating carbon to 5X using one of several processes (e.g., heated discharge conveyor or Al filter cake dryer) 153 hr of successful testing processing slurried carbon separately using modified SCWO reactor; concluded on 12/2/01. M22 propellant hydrolysate/dunnage slurry Aluminum precipitate caused problems in SCWO reactor and downstream components Implementation of improved filtration technique and verification of correct SCWO feed composition by sampling and analysis Treatment of hydrolysate slurry, including filtration of aluminum compounds, was successfully tested in MD runs (see also Table 5-1). FINDINGS AND RECOMMENDATIONS Findings Finding (Blue Grass) GA-1. The GATS process appears to have reached a level of maturity sufficient for construction of a full-scale facility at Blue Grass, not-withstanding the issues raised in the subsequent findings. The testing that has been conducted has shown that the General Atomics SCWO system is a high-maintenance operation; however, the level of maintenance that is required for the application of the SCWO system in particular, and the GATS process in general, in a Blue Grass facility is not beyond the ability of well-trained operators and maintenance personnel. Finding (Blue Grass) GA-2. In the committee’s opinion, the number of SCWO reactor liner changes required to process the stockpile at Blue Grass, while high, is manageable. Finding (Blue Grass) GA-3. The committee still has some concern about possible problems when scaling up from the existing GATS SCWO reactor to the full-scale design. Finding (Blue Grass) GA-4. Although the General Atomics cryofracture process was not demonstrated during the ACWA program, the committee believes the technology to be sufficiently mature for implementation in a Blue Grass facility. This finding is based on the results of the tests conducted between 1982 and 1993, during which time 3,695 explosively configured, agent-simulant-filled projectiles, rockets, and mines were opened by cryofracture. Finding (Blue Grass) GA-5. The GATS process for handling energetics within the ERH will result in the mixing of a lead-containing propellant (M28) with tetrytol when rockets with tetrytol bursters are treated.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot This combination might lead to the formation of lead picrate. Finding (Blue Grass) GA-6. The ERH was tested in a batch mode; however, the design proposed for both the ERH and PRH for Blue Grass is operated in a continuous mode. The resulting equipment is an ERH 50 feet long and a PRH 40 feet long. In the opinion of the committee, this equipment may prove difficult to maintain. Recommendations Recommendation (Blue Grass) GA-1. The hydrolysis streams for the processing of propellant and burster materials must be kept separate until the formation of lead picrate has been ruled out. Recommendation (Blue Grass) GA-2. The technology provider should consider that the ERH and PRH units for a full-scale GATS process at Blue Grass be batch units similar in design to those tested.