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6 General Atomics Technology Package INTRODUCTION AND OVERVIEW The technology package submitted by General Atomics is summarized in Table 6-1 and the flow charts in Figures 6-1 through 6-4. This package is comprised of four basic technologies. · The munitions are disassembled using the Army's baseline disassembly process, modified to include cryofracture of projectiles and mortars once the energetic materials have been removed. · The chemical agents and energetic materials are decomposed (separately) using caustic hydrolysis. · SCWO (supercritical water oxidation) is used to treat the hydrolysates of agent and energetic de- struction. · High-temperature heating is used to decontami- nate metal parts to a 5X level. TABLE 6-1 Summary of the General Atomics Approach General Atomics' technology package is designed to treat the following materials: · projectiles and mortars containing explosives and agent · rockets containing explosives, propellant, igniters, and agent · land mines containing explosives and agent · dunnage, including pallets, metal banding, and DPE, some of which may be contaminated with agent DESCRIPTION OF THE TECHNOLOGY PACKAGE Disassembly of Munitions and the Removal of Agent/Energetics General Atomics proposes using baseline disassem- bly methods with the modifications described below. Major Demilitarization Operation Approach(es) Disassembly of munitions Rockets and mines. Army baseline disassembly process with minor modifications. Projectiles and mortars. Army baseline disassembly process to remove energetics with minor modifications, followed by cryofracture of downloaded munitions to provide better access to agent. Treatment of chemical agent Caustic hydrolysis; SCWO treatment of hydrolysate. Treatment of energetics Waterjet wash-out of energetics from casings; caustic hydrolysis; SCWO treatment of hydrolysate. Treatment of metal parts Heat in electrical metal parts furnace to SX. Treatment of dunnage Shred, macerate, slurry; caustic hydrolysis of slurry; SCWO treatment of hydrolysate. Disposal of waste Solids. Analyze and send dry salts to landfill, possibly after stabilization. Liquids. Analyze and discharge condensate from evaporation of salts to wastewater treatment plant. Gases. Discharge to atmosphere after HEPA filtration and activated carbon adsorption; continuous monitoring for agent. 88
GENERAL ATOMICS TECHNOLOGY PACKAGE Disassemble p roj ecti I es/mo rta rs to C ryof ractu re remove energetics _ | projectiles/mortars ~HI to access agent and \ / Punch/shear fuses and metal parts \ / bu raters munitions Punch and drain agent Dispose of I from rocket dunnage l \~1 Punch and drain agent | from mine Shear rocket to access fuse, bu rater, and propellant / Punch mine _ ~bu rater/booster / FIGURE 6-1 Schematic drawing of General Atom~c's proposed technology package. Rocket Disassemb/y M55 rockets are processed through the baseline dis- assembly rocket-shear machine, and the drained agent is pumped to a surge tank prior to hydrolysis. The rocket pieces (containing the propellant and other en- ergetic materials) are gravity-fed through the discharge chute of the explosion-containment room to the next treatment step, hydrolysis of energetics. The following modifications to the rocket-shear machine are included in the General Atomics proposal: . an increase in the number and change in the loca- tions of the cuts to reduce the size of the pieces of energetics fed to the hydrolysis reactor · an increase in the number and diameter of the holes punched in the agent cavity · the addition of a flushing step, whereby hydroly- sis solution is injected through pressure nozzles inserted into the agent cavity These modifications are intended to facilitate the draining of agent and minimize cross-contamination and co-processing of agent and energetics in the hydrolysis step. Land Mine Disassemb/y General Atomics proposes modifying the baseline mine-unpacking operations and mine machine to im- prove draining and flushing of mine bodies and to in- crease access to the bursters and the booster. The drained liquids and flush solutions are pumped to surge tanks from which they are fed to the hydrolyzers. The mine bodies and energetic materials may, still be con 89 l Hydrolyze agent Hyd rolyze explosives Decontaminate metal parts Treat agent hydrolysate with SCWO Treat explosives hydrolysate with SCWO -| 5X metal parts | laminated with residual agent and energetics, at this stage. They are gravity fed through the discharge chute of the explosion-containment room to the hydrolysis step. Projectile and Mortar Disassemb/y General Atomics proposes using the baseline re- verse-assembly process to remove the energetics from projectiles and mortars. Energetic materials are con- veyed through the explosion-containment room dis- charge chute to the energetics hydrolysis treatment step. General Atomics proposes modifying the baseline process by using cryofracture to provide access to the interior of the munition bodies. General Atomics be- lieves that cryofracture will provide better access to the agent than the baseline process method in which burster wells are pulled and the agent cavity is drained. In the cryofracture operation, the munitions (with explosive charges removed) are loaded, via a special carrier, onto a cryocooling conveyor. The conveyor lowers the munitions into and slowly moves them through a bath of liquid nitrogen (77 K; -321°F) to embrittle the casing. At the bath exit, the munitions are transferred to a hydraulic press where they are frac- tured into pieces while they are still cold. The fractured munition components and chemical agent are then discharged through a chute to the projec- tile rotary hydrolyzes (described in the next section) for further treatment. The metal parts are washed with alkali solution applied through high-pressure nozzles to clean out any remaining agent and transferred to a chemical reactor for further treatment.
9o ~ E ra I ~ ~ o _ _ I __----1 l -2°9 l ~ I ~ L _ _ i_ _ _ 9 ~ ~ o I___ ___--- o~_~ A_ -- ~g~5~ T ~zing l _ __. . ~1 I rid 1 ~ Ut ~;~1 ~ L _ _ _ _ _ _ _ _ _ _ - t- - - ~ I ~I o ~_~: , L_____ _: ~ ~
GENERAL ATOMICS TECHNOLOGY PACKAGE I | Receive | | Manually | I I l munitions ~ unpack I ~from storage munitions ~I ~1 11[J ~ uncontaminated Monitor/ dunnage ~separate offsite for dunnage disposal , Treat metal parts to 5X in batch ~ metal parts c furnace b _ Sort/shred/ slurry/ Treat slurry a decontaminate ~ with SCWO dunnage FIGURE 6-3 Block flow diagram for treatment of rockets. Treatment of Chemical Agent The agent drained from the rockets and mines is con- tinuously fed from the surge tank to the agent hydroly- sis reactor (AHR), a continuously stirred tank reactor (Levenspiel, 1962), where it is hydrolyzed using the Army' s agent neutralization process (see Appendix D.~. The AHR is operated at 90°C and atmospheric pres- sure and is blanketed with nitrogen. Although agent hydrolysis should not generate any gases, the nitrogen blanketing is used as a precaution. The AHR effluent gas, mostly nitrogen, is passed through activated car- bon filters and released to the plant ventilation system, which is vented through additional activated carbon fil- ters prior to release to the environment. The hydrolysate from the AHR is pumped to a stor- age tank where it is sampled and analyzed for agent. If the agent concentration exceeds design specifications, the hydrolysate is returned to the AHR to continue the hydrolysis. Otherwise, the hydrolysate is fed to the agent hydrolysate SCWO system. 91 l Decontaminate l l metal parts to 5X l ~in HDOb~d l . ..... __ l ~--------- 1 Shear fuze/ l burster/ l l Hydrolyze Treat l ~ rocket motor ~energetics ~ hYdrOIysate 1 ~ ~1 1 1 1 ·---------------_____ . 1 Punch/drain _ ~, agen and warhead n RSM e __________ 1 1 Notes: a. Dry salt/solids and ship off-site for disposal b. Ship 5X metal/residue off-site for disposal c. May require decontamination/further processing if contaminated (unlikely) d. HDC = baseline heated discharge conveyor e. RSM = baseline rocket shear machine The agent from the cryofractured projectiles and mortars may contain shards of solids that cannot be readily treated in a stirred tank reactor. Therefore, this agent is treated in the projectile rotary hydrolyzer (PRH). The PRH is a horizontal cylinder with a high lip at each end and slip seals between each lip and a solid bulkhead. It is operated at atmospheric pressure and equipped with a jacket that can be fed either steam or coolant to maintain a temperature of 90°C (194°F). The PRH rotates slowly, tumbling the contents, mixing them, and moving them down its length. At the feed end of the PRH, caustic is directed through high-pressure nozzles to flush agent from the solid metal parts, forming a hydrolysate solution. At different points in the PRH, the solids mixed with the hydrolysate are passed over screens that drain the free hydrolysate through a surge tank to the AHR. The PRH cleans residual agent from the munition fragments and acts as the primary reactor for agent hydrolysis. The AHR hydrolyzes any residual agent not hydrolyzed in
92 ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS , Punch ., l burster/ l l _ l booster ~ · in Ml N c I | Decontaminate | I metal parts to l l 5Xin HDCb,d l ~ ' . energy l . . . . . . . . . l l . , ~ I ___ ___ ___ ___ ___ ___ ___ I Punch /drain I ~, | Receive | | Manually| ~ I agent kind | ~ ~ | Hydrolyze I r Treat l munitions ·1 unpack I ~mine in I · agent · hydrolysate l l from storage muni tions l lMINC l l with SCWO e~ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . ~L ~ u ncontar n ~ nated Sepa rate/ dunnage ~monitor offsite for dunnage disposal 1 l , Treat metal parts Sort/shred/ I to 5X i n batch sl u try/ Treat sl u try a l metal parts _ decontaminate · SCWO l furnace b dunnage FIGURE 6-4 Block flow diagram for treatment of land mines. the PRH. The effluent gases from the PRH are scrubbed and passed through carbon filters before being released to the plant ventilation system. Treatment of Energetics Energetic materials removed during the disassem- bly process are conveyed through the explosion-con- tainment room discharge chute into the energetics ro- tary hydrolyzer (ERH). The ERH, similar in design and operation to the PRH, also operates at atmospheric pressure and approximately 90°C (194°F), which is above the melting point of TNT. The technology pro- vides claims that the combination of rotary mixing, melting, and base hydrolysis converts solid explosives and energetics into a hydrolysate that can be treated by SCWO. (Treatment of the screened metal parts is dis- cussed below.) The results of tests conducted by Gen- eral Atomics and Los Alamos National Laboratory are included in the proposal to support the use of the ERH (General Atomics, 1998~. _ 1 Notes: a. Dry salt/solids and ship offsite for disposal b. Ship 5X metal/residue offsite for disposal c. MIN = baseline mine machine d. HDC = baseline heated discharge conveyor Hydrolysis of the energetics is expected to take from one to six hours, depending on temperature, mixing, and concentration of NaOH. At the time the technol- ogy package was submitted, neither optimum param- eters nor the optimum size of the reactors had been determined. The proposal states that the rotary hydro- lyzer for the final process will be oversized to extend residence time, if necessary. The hydrolysate from the ERH is pumped to a stor- age tank where it is sampled and analyzed for agent and energetics. If either is found in excess of allowable concentrations, additional time is allowed to continue the hydrolysis. If analysis shows that the hydrolysate is acceptable, it is then fed to the energetics hydrolysate SCWO system. The effluent gas from the ERH consists of nitrogen, water vapor, a small quantity of hydrogen produced by the chemical reaction of aluminum parts with caustic, and traces of volatile organic compounds. This effluent gas is treated in the same manner as effluent gas from the AHR.
GENERAL ATOMICS TECHNOLOGY PACKAGE Treatment of Hydrolysate with Supercritical Water Oxidation The General Atomics technology package includes two of SCWO units-one to treat the hydrolysate from agent neutralization and one to treat the hydrolysate from energetics neutralization. The basic SCWO process is described in Appendix F. Only the specifics of General Atomics' implementation of SCWO are described here. To treat agent hydrolysate, General Atomics pro- poses using a vertical, cylindrical SCWO reactor, simi- lar in configuration to systems General Atomics tested for the Army in 1997 (GA, 1997; NRC, 1998~. In these tests, mineralization levels for the organic constituents in the hydrolysate were high (i.e., conversion of carbon to carbon dioxide, hydrogen to water, and phosphorus, chlorine, and sulfur to inorganic phosphates, chlorides, and sulfates, respectively). In addition, extremely low levels of light organic compounds were found to be present in the off-gas stream (NRC, 1998~. There was, however, significant corrosion and erosion of the tita- nium from the reactor walls (NRC, 1998~. Therefore, General Atomics proposes using a platinum liner in the ACWA application. The reactor operating pressure and temperature are approximately 650°C (1,200°F) and 230 aim (3,400 psi). Treatment of Metal Parts The metal parts that collect on the screen at the exits of the ERH and PRH are deposited on electrically heated discharge conveyors, which raise the metal tem- perature to more than 1,000°F for at least 15 minutes, thereby meeting the 5X decontamination criterion. General Atomics expects that some small fuze-train explosives may escape complete hydrolysis in the ERH and PRH and that these will initiate on the conveyors. General Atomics expects to show in its demonstrations that the initiation of fuzes will not be energetic enough to damage the conveyors. Treatment of Dunnage Dunnage consists of materials, like wooden pallets, metal banding, and DPE suits, some fraction of which iGeneral Atomics experienced problems in fabricating a platinum liner for the ACWA demonstrations, so an Inconel 718 reactor with no liner was used instead. 93 may be contaminated with agent. General Atomics pro- poses to treat this material by shredding and separation of the metals, followed by SCWO treatment of the non- metals and 5X treatment of the metals. A low-speed shredder breaks up pallets, boxes, and other bulk dunnage or process waste materials. Next, the rough-shredded wood is reduced to small chunks in a hammer mill and then to fine particles in a micronizes. The micronized product is mixed with water and moved to a hydropulper where it is reduced to particles smaller than 0.5 mm in diameter, which is well within the tar- get size (less than 1 mm) for SCWO processing. Dust from the micronizer is collected in a bag-house, drummed, and combined with the reduced process feed for further treatment. Plastic and rubber materials are treated the same way, except that the hammer mill is replaced with a granu- lator. The output of the granulator is cryocooled (using liquid nitrogen) prior to being fed to the micronizes. Carbon steel pieces are separated out magnetically and sent to the metal parts furnace (MPF) for 5X de- contamination. The MPF is identical to furnaces used to decontaminate metal, except induction heating is used rather than natural gas. The MPF is vented through activated carbon and HEPA filters. Process Instrumentation, Monitoring, and Control The process parameters to be monitored are routine and include pH, temperature, and pressure of all streams. All monitors are commercially available. Feed Streams The technology provider generated a mass balance for the processing of 80 VX-filled 155-mm projectiles per hour (GA, 1998; Appendix B). This balance is for the entire plant except for the brine reduction area and the plant ventilation system. Feed streams are shown in Table 6-2. General Atomics' technology package requires only two reagent feeds: (1) oxygen or air to the SCWO sys- tem and (2) sodium hydroxide (caustic) for hydrolysis of agent and energetics and to neutralize the acids pro- duced by the SCWO destruction of the hydrolysate. The process is a net producer of water (due to
94 TABLE 6-2 Process Inflow Streams for the General Atomics Technology Package (80 VX-filled 155-mm projectiles per hour) Component ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS Amount (lb/hr) · metal parts that have been cleaned and decontami- nated to the 5X condition · spent carbon (from treating gas and exhaust air)- although this might be treated on site by the SCWO equipment vx 480 · spent HEPA filter elements Munition dunnage Nonprocess dunnage Steel 420 472 7,102 Aluminum Explosives NaOH for munition handling 607 to energetics rotary hydrolyzer 277 Total 884 Water with caustic to agent hydrolyzer to agent hydrolyzer to energetics rotary hydrolyzer with caustic to ERH to dunnage processing Total 220 911 2,370 2,194 416 6.548 12,439 The mass flows for the waste streams are shown in Table 6-4. Start-up anti Shutdown Start-up and shutdown are summarized on a process- by-process basis in Table 6-5. The shutdown proce- dure is the reverse of the start-up procedure-the flow of contaminated material is replaced with a flow of clean hydrolysis solution. No final shutdown (decom- missioning) procedures are included in the technology package. EVALUATION OF TH E TECH NOLOGY PACKAG E Nitrogen6,999 Process Efficacy to HDC #1470 to HDC #2470 Effectiveness of Munitions Disassembly Total8,407 Kerosene Decontamination fluid s37 400 Plant ventilation process air 48,9s6 Total plant inflow Source: GA, 1998. 80,415 SCWO) and, except for start-up, does not require addi- tional water. Liquid nitrogen is required for the cryocooling processes and for inert blanketing of reac- tors and tanks. Waste Streams The following waste streams leave the plant: · dried salts from SCWO that probably contain traces of organic materials and potentially hazard- ous metals - gases from process vents and from the SCWO sys- tems that are passed through HEPA and activated carbon filters (Table 6-3 shows the air emissions from the process and indicates their general type) General Atomics introduces two new technologies into the disassembly process causticjet clean-out and cryofracturing of projectiles and mortars. Both tech- nologies have been used in other industrial and muni- tions disposal processes. Waterjet clean-out of opened shells appears to be a reasonable way of breaking up and flushing away energetic materials in the cut and broken pieces without creating a high shear, which would increase the possibility of accidental detonation or deflagration. The committee, therefore, concluded that this modification was not likely to create opera- tional problems; however, no data are available on the amount of residual material that would remain after waterjet cleaning. In 1991, an NRC panel evaluated the use of cryo- fracture for accessing agent and energetic components in chemical munitions prior to incineration (NRC, 1991~. At that time, the panel was concerned that the incineration of munition fragments after cryofracture was not adequately understood and concluded that cryofracture was not necessary in conjunction with in- cineration because the heat of incineration would re- move residual agent, including gelled agent.
GENERAL ATOMICS TECHNOLOGY PACKAGE TABLE 6-3 Potential Air Emission Points for the General Atomics Technology Package Source Type Disposition SCWO system pressure let-down particulates, vapors APCD,a environment and liquid-gas separation Washing of metal parts droplets, particulates, vapor room ventilation Punching and draining of munitions droplets, particulates, vapor room ventilation Cryofracturing droplets, particulates, vapor room ventilation Thermal treatment (SX) furnace vapor APCD, environment Building ventilation system particulates, vapor APCD, environment fair pollution control device In the present application, the ACW Committee has concluded that a key factor in the decontamination of munitions is good access to the residual agent in the munitions to ensure that the washing and hydrolysis are effective. Although improving access to the agent cavity is desirable, the committee found no data to in- dicate that cryofracturing would provide better access to liquid agent than more conventional approaches, such as shearing. The ACW Committee then investigated whether the cryofracture process might improve safety or operabil- ity over the baseline process for accessing agent in pro- jectiles and mortars. As discussed in Appendix C, the baseline disassembly process has encountered some difficulties in opening the agent cavity (removing the burster well) and draining the agent. Using cryofracture TABLE 6-4 Process Outflow Streams for the General Atomics Technology Package (80 VX-filled 155-mm projectiles per hour) Component Amount (lb/hr) Salt and other nonmetal solids from agent SCWO from energetics/dunnage SCWO Total Treated steel Treated tramp metal and glass Water from agent SCWO from energetics/dunnage SCWO Total Total plant outflow 1,181 949 2,130 7,102 120 3,913 10,369 14,282 80,414 Source: GA, 1998. 95 to break open the rounds would eliminate the difficul- ties with pulling the burster wells, some of which are welded in place. Furthermore, if the agent is gelled or crystallized, cryofracture should represent an improve- ment over the baseline suction approach. The commit- tee, therefore, concluded that if the robustness and abil- ity of cryofracture to access the agent cavity could be verified, cryofracture might improve performance over the baseline disassembly process. Effectiveness of Agent Detoxification Agent hydrolysis has been studied extensively, and full-scale plants are being constructed at Aberdeen, Maryland, and Newport, Indiana, to destroy the agent stored there in bulk. These plants are scheduled to be completed before the full-scale implementation of ACWA technologies. Thus, the experience from these facilities should be available to the ACWA program. General Atomics would rely primarily on hydrolysis for achieving a high destruction efficiency for agents (99.9999 percent). (See Appendix E for a detailed dis- cussion of agent hydrolysis.) Effectiveness of Energetics Destruction Although this process appears to be capable of de- stroying the energetic materials, the rate at which these materials will be processed cannot be determined at this time. The rate-limiting step for energetic destruc- tion is the hydrolysis reaction (see Appendix E), which, in this application, is mass-transfer limited (i.e., the chunks of energetic material must be dissolved into the hydrolysis solution, and the rate of dissolution is
96 ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS TABLE 6-5 Routine Start-up Procedures for the General Atomics Technology Package Baseline disassembly Follows the standard procedures developed by the Army. Cryofracture Liquid nitrogen bath is filled with nitrogen and munitions introduced. AHR Process monitors and controls are activated. Reactor is filled with caustic solution and brought to temperature. Agent or contaminated solids are introduced, as appropriate. ERH and PRH Process monitors and controls activated. Reactor is filled with caustic solution and brought to temperature while liquid is recycled. Solid materials are introduced. SCWO reactors Process monitors and controls are activated. Reactor is fed a mixture of pure water. Reactor is brought to temperature using auxiliary heaters. Kerosene and oxygen are gradually introduced at operating temperature to begin the chemical reaction. Kerosene is gradually replaced with hydrolysate. Evaporator/crystallizer Process monitors and controls and condenser coolant flow are activated. Tested SCWO effluent is introduced. System is brought up to operating temperature. Hydrolysate is introduced. Filter belt is activated. limited by their surface area). The smaller the pieces, the faster the hydrolysis. At this point, there is little data to confirm that the chunks from the disassembly processes would be small enough to dissolve at the pro- jected rates. If testing shows that the actual rate is dif- ferent from the projected rate, the capacities or number of reactors will have to be adjusted. Substituting a rotary reactor for a stirred reactor ap- pears to alleviate the problem of jamming when metal parts are introduced. Tumbling, which will occur in the rotary reactor, is a standard industrial method of mix- ing solids with liquids. Effectiveness of Supercritica/ Water Oxidation The treatment of the agent hydrolysate by SCWO and the treatment of the SCWO effluent by evapora- tion and filtration are also being designed into the fa- cility at Newport, Indiana. Experience from operating this facility should be available to the ACWA program for follow-on assessments. However, as is pointed out in Appendix F and in Using Supercritical Water Oxi- dation to Treat Hydrolysate from V7( Neutralization (NRC, 1998), although there is a keen interest in using SCWO for treating a variety of wastes, very little pro- duction experience is available. SCWO appears to be capable of decomposing the hydrolysis products into waste streams that can be dis- posed of in an environmentally sound manner. (Mus- tard does contain volatile low molecular weight chlori- nated hydrocarbons that can be difficult to treat, but they are expected to be oxidized by SCWO. However, this will have to be demonstrated.) The volume of air emissions from the process is small and will be fur- ther treated by activated carbon and HEPA filters. With proper monitoring of the adsorbers and filters, these small emissions should easily meet regulatory requirements. The aqueous stream from the process consists mostly of pure water, the vast majority of which is recycled to the process. In the opinion of the committee, the small amount of excess water appears to be acceptable to a wastewater treatment plant. The solid waste from the process consists mainly of sodium salts, phosphate, chloride, fluoride, and sulfate. Most likely, these solids will contain some hazardous compounds and elements (how much is not known yet). In the committee's opinion, the nature of this stream and the probable concentration of hazardous constitu- ents should not prevent its being stabilized and safely disposed of in a hazardous-waste landfill. However, this conclusion must be confirmed by further studies. Sampling and Analysis The process appears to have no unusual sampling or analytical problems and requires only well developed and generally accepted procedures. Maturity The overall process is a combination of several inte- grated operations, all of which are operated in a batch or semibatch mode. All of the technologies, with the exception of SCWO, have a substantial background, although some require demonstrations for their use
GENERAL ATOMICS TECHNOLOGY PACKAGE with chemical weapons. The least mature operations are described below. Hydrolysis of Energetics. Energetic materials have been hydrolyzed safely in the laboratory for more than a century, but large-scale hydrolysis has been rare. As noted in Appendix E, the problem is the size of the pieces being hydrolyzed. Because hydrolysis is a solid- liquid reaction, it occurs only at the solid-liquid inter- face. If a fixed mass of energetic material is broken into many small pieces, rather than a few larger ones, a much larger total surface area is presented to the hy- drolyzing solution, and the hydrolysis rate can be pre- dicted with reasonable accuracy. However, the sizes of the pieces of explosives and propellant can vary widely in each batch, which could slow the hydrolysis or even stop it if products are deposited on the surface layers. Avoiding this problem will require additional develop- ment for this technology and for other technologies that propose to use hydrolysis to destroy the energetics. SCWO Operation at the Proposed Scale. The only SCWO system in commercial operation belongs to Huntsman Corporation and is located at their Austin, Texas, facility (Lyon and Ullrich, 1998~. This system has been operating for about two years, treating ap- proximately five gallons per minute of wastewater con- taining approximately 10 percent organic material. This system is about one-fourth the size of the system pro- posed by General Atomics. A reactor with the same design proposed by General Atomics has been tested on a variety of materials similar to those being treated in this program, but the maximum duration of the tests has been about 40 hours (NRC, 1998~. General Atom- ics has recently shipped a SCWO system for treating shipboard wastes to the U.S. Navy (Hazelbeck et al., 1998), and the Army is planning to use SCWO units for treating VX hydrolysate in Newport, Indiana, with SCWO systems similar in design and size to General Atomics' proposed system. SCWO Durability. The durability of the components and materials of the SCWO system in the highly corro- sive environment generated by the treatment of feed materials containing large amounts of sulfur, phospho- rus, and chlorine must be determined (NRC, 1998~. General Atomics recognizes this problem and has presented materials-corrosion data in its proposal 97 identifying potential materials of construction that would minimize corrosion. Platinum linings are plan- ned for areas of the reactor that will be particularly vulnerable to corrosion. However, the fabrication of a platinum liner for the ACWA demonstration was not successful. General Atomics proposes developing a scheduled maintenance and replacement program based on anticipated corrosion rates, but these rates have not been established. Therefore, materials of con- struction remains a critical issue that must be resolved. The treatment of dunnage using SCWO also raises some concerns regarding durability. First, the slurry stream will be very large. In fact, because of the vol- ume of this stream, General Atomics initially proposed that the dunnage be tested and that uncontaminated dunnage be sent off site for disposal. Second, the abil- ity of existing pumps to pump the slurry up to the high SCWO pressures has not been tested. General Atomics claims that a proprietary pump has been developed, but no data on its reliability was provided to the co~it- tee. Third, the behavior of solid materials in the SCWO, but reactor is unknown. Even though metal will be re- moved during the size-reduction process, some metal shards will probably pass through to the SCWO, but it is not known whether the SCWO system will be ca- pable of handling them. Process Robustness The overall process appears to be capable of with- standing the following problems. Incomplete Drainage of Agent or Gelled Agent in the Munitions. Once the free liquid has been drained from rockets and mines, the whole munition will be flushed with hot hydrolysis solution or water and then immersed in hydrolysis solution for an extended pe- riod of time. Any remaining agent will be destroyed by subsequent 5X treatment. Although this process ap- pears promising, it has not been demonstrated that the flushing and immersion steps will fully remove any gelled agent. If gelled agents were to remain, process- ing rates might have to be reduced to allow for in- creased residence time in the furnace. Cryofracture, which will be used to access the agent in projectiles and mortars also appears promising but has not yet been demonstrated to improve on the baseline draining method.
98 ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS Variations in the Composition of Agent or Energetics. Variations in composition of the feed material might affect hydrolysis and SCWO. Because hydrolysis will be performed on a batch basis, any failure in the hy- drolysis stage of the process could be corrected by ex- tending the time for hydrolysis or increasing the con- centration of reagent. SCWO has already achieved exceptionally high destruction levels for a wide variety of organic compounds. In addition, the semi-batch pro- cess allows for the SCWO effluent to be collected and held until it has been thoroughly analyzed. General Atomics indicates that if the effluent does not meet specifications after initial processing, it can be retreated until it does meet specifications. Difficulty in Removing Nose Closures on Projectiles and Mortars. The use of cryofracture eliminates the need to remove the nose closures on projectiles and mortars. Cryofracture appears to be a robust technol- ogy, and the equipment is commercially available at the required scales. One common use of cryofracture is to break up waste tires for use as fuels for boilers or cement kilns or to reduce their volume for disposal in a land-fill. General Atomics cites research indicating that the cryofracture process has been improved significantly since it was developed in the late 1980s. The cited re- search is an extensive series of tests General Atomics conducted for the Air Force in which solid-fuel rockets were frozen in liquid nitrogen and fractured success- fully. Because the munitions involved in this program are smaller than the Air Force rockets and will not con- tain explosives, new problems are not expected to arise. Monitoring and Contro/ The process does not require any unusual monitor- ing or control systems. All of the monitoring and con- trol systems are commercially available and appear to be reliable. Applicability Before a plant based on this technology package would be ready for operation, many of the technologies will have been used for the destruction of chemical agents at Newport and Aberdeen. To date, some of the technologies (SCWO of propellant hydrolysate, cryo- fracturing of projectiles and mortars) have only been tested at reduced scale and/or throughput. In spite of these limitations, the process appears to be a reason- able application of the technologies. The General Atomics technology package addresses all of the mu- nitions identified in DOD's REP; therefore, it should be applicable to any storage site. Process Safety The General Atomics technology package would re- quire the following unique equipment: · a modified (from baseline) rocket-shear machine · a modified (from baseline) mine machine · rotary hydrolyzers (based on a modified rotary- drum dryer design) for the hydrolysis of energet- ics from all munitions and the decontamination of metal parts after the cryofracture of projectiles and mortars · conveyors to carry projectiles and mortars through the cooling vessels prior to cryofracture · robots to unpack projectiles end mortar rounds end place them in the cryocoolers (may be similar to baseline pick-and-place robots) · a modified (from baseline) induction-heated MPF and electrically heated discharge conveyors · commercial hydropulping equipment modified to shred, mascerate, and form a slurry containing contaminated dunnage · SCWO reactors for the destruction of the hydroly- sates of agent and energetics Based on the consequences of failures in both the low- and high-pressure systems, the committee con- cluded that there were no unusual or intractable pro- cess safety problems. The cryofracture process (cryo- cooling and press operation) operates near the atmospheric boiling point (-196°C; -321°F) of liquid nitrogen. The hot water jet and hydrolysis processes operate at relatively low temperatures (90°C; 194°F) and low pressure (near atmospheric), eliminating the problem of significant stored energy. The electrically heated discharge conveyors and MPF operate at 1,000°F (538°C). Hydrolysates will be sampled for the presence of agent and energetics before release to the SCWO reactors. The SCWO reactors operate at 230 aim
GENERAL ATOMICS TECHNOLOGY PACKAGE (3,400 psi) and a temperature of 650°C (1,200°F). All off-gases will be passed through the facility ventilation system (which includes carbon HEPA filtration). Worker Health and Safety The proposed system provides "defense in depth" because agent and energetic destruction are verified after both sequential steps for all munitions. The sepa- ration of energetics from agent, followed by the de- struction of both materials in caustic solutions mini- mizes the hazard of explosions. In addition, these processes are operated in structures designed to con- tain explosive overpressure. The disassembly processes are derivatives of the baseline processes for disassembling rockets and land mines and are not considered to represent new or in- creased levels of hazard. These processes will be con- ducted in vessels or structures designed to withstand explosive overpressure in case an initiation does occur. The method proposed for the disassembly of projec- tiles and mortar rounds (cryofracture) is unique. The hazard level from cryofracture appears to be no greater than the level for baseline disassembly. However, the General Atomics hazard analysis does identify sce- narios in which fragments containing energetic might be squeezed and initiated during transfer from the cryofracture press to the rotary hydrolyzers. Presum- ably, these hazards can be accommodated in the equip- ment design, but the design must also minimize worker exposure to agent during the repair or replacement of parts broken or damaged by explosions. General Atomics plans to hydrolyze different types of energetic materials simultaneously in the same reac- tors, which the committee believes could lead to the formation of compounds that are both energetic and sensitive (see Appendix E). Therefore, energetic mate- rials should be processed in separate reactors unless testing shows that sensitive compounds are not formed. The hydrolysis processes that include dissolution of aluminum parts (e.g., M55 rockets) will generate hy- drogen gas, which could conceivably rise to concentra- tion levels that permit ignition in the process areas dur- ing upset conditions. Nitrogen purge gas is used to keep hydrogen concentrations below the level of concern. High pressures, the primary cause of gas leaks into ventilated areas, will be minimized because all parts of 99 the process except the SCWO reactors operate at very low pressures. ProceL~Ls-veL~Lsel vanor L~naceLs should alwavLs . , . . . ~ ~ , maintain a positive pressure to prevent in-leakage of air and to ensure purge gas flow to process vessel headspaces. The most significant issue related to worker safety may be during maintenance in DPE LSuitLs on Lsnecial . . · . . Czech equipment te.g., the rotary hydrolyzers and cryocooling conveyors), which have systems operating in a caustic solution and at very low temperatures. Ex- perience with such systems is limited, and start-up problems may require significant maintenance for the full-scale application, thereby increasing the risk of worker exposure to agent. A second issue related to worker safety is the presence of nitrogen gas in cryofracture equipment, which can lead to very low concentrations of oxygen. As noted by General Atom- ics, nitrogen is an asphyxiant, so workers will have to be supplied with fresh air, and work areas will have to be monitored. The SCWO reactors and associated water supply systems will operate at high pressure, representing sig- nificant sources of stored energy. Hence, it will be very important that the reactors and associated piping be designed and maintained to minimize ruptures and leaks. Secondary containment should be sized to ac- commodate a hypothetical "worst case" rupture of the SCWO reactor. SCWO system failures could require extensive repair work that requires either DPE suits or protective gear for hazardous chemicals and, thus, present an opportunity for worker exposure during maintenance. Fuze bodies and booster pellets that are not dissolved in the caustic solution also represent an explosive haz- ard in the rotary hydrolyzers and heated discharge con- veyors. The technology provider intends to demon- strate a technology that will reduce size mechanically to facilitate full dissolution. In addition, the hydrolyzers and heated discharge conveyors will be designed to withstand initiation of these energetic components. The primary hazardous materials used during agent and energetic destruction are sodium hydroxide, liquid and gaseous oxygen, and methane (natural gas). So- dium hydroxide will be delivered in solid form and dis- solved in water to make a 40 percent caustic solution, which is strongly corrosive to all body tissue. Liquid and gaseous oxygen and methane are handled routinely
100 ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS and safely in many industries and do not represent an unusual hazard to workers. Public Safety Accidental releases of agent or other regulated sub- stances to the atmosphere or the groundwater system are extremely unlikely. However, hold-test-release sys- tems for all process effluent gaseous streams are not included in the proposal. Although caustic scrubbing and activated carbon and HEPA filters should be ad- equate (judging from experience with baseline tech- nology), they do not meet the stakeholder hold-test- release criterion for all gaseous effluents produced during normal operation. The primary cause of a re- lease of material containing agent or other regulated substances would be an explosion or the rupture of a pipe or vessel, but the likelihood of such an event at the conclusion of the design process for the full-scale facility should be extremely small. The design pro- cess is assumed to include a QRA (quantitative risk assessment). Human Health and the Environment The environmental impact of the proposed process appears to be minimal. All handling of agent and all processing are conducted indoors in sealed rooms that are vented through HEPA and carbon filters. Streams handled are very small and manageable by the stan- dards of almost any industrial-scale process. Process air releases are small enough that they could be col- lected and stored for analysis to verify their quality prior to release. Eff/uent Characterization The liquid effluents consist of water from the evapo- rator/crystallizer used to produce the solid filter cake. This material is essentially distilled water and should not pose a significant hazard to human health or to the environment. The solid waste from the process, con- sisting of dried filter cake, is likely to require stabiliza- tion prior to disposal in a hazardous-waste landfill. Not enough information is available on the process to determine the hazardous constituents (if any) in the gaseous effluent, especially from the pressure let-down of the SCWO reactor. If HEPA and carbon filters are used properly, these discharges should meet regulatory standards. However, this must be confirmed through comprehensive testing. Completeness of Eff/uent Characterization The liquid and solid effluents are well characterized. Only the major components of the gaseous effluents have been characterized. The gaseous emissions will have to be characterized for HRAs and environmen- tal risk assessments as required under current EPA guidelines. Eff/uent Management Strategy The proposed strategy appears to be reasonable and has a number of built-in redundancies that should pro- tect public health and the environment. Resource Requirements The power and other resource requirements for the system should pose no difficulties. Because the system is a net producer of water, it does not require a large water inventory. Table 6-3 shows that about 1,800 lb/ hr of water is generated in the process. Thus, steam will have to be vented from the dryer or discharge con- densate from the brine reduction area. Environmenta/ Compliance and Permitting The combination of technologies in the General Atomics technology package is not expected to lead to environmental compliance or permitting problems. All process waste streams except the SCWO off-gas will be evaluated prior to release to confirm that they are either free of regulated substances or that they are at acceptably low concentrations. The SCWO off-gas is scrubbed, monitored, and passed through activated car- bon filters. STEPS REQUIRED FOR IMPLEMENTATION The following steps would have to be taken to imple- ment the General Atomics technology package.
GENERAL ATOMICS TECHNOLOGY PACKAGE 1. Conduct tests of the cryofracture process to as- certain if it provides better access to the agent cavity in projectiles and mortars then the baseline disassembly process. 2. Sample and analyze air emissions from the dem- onstration system. The air emissions will have to be measured to a level of detail and accuracy that can be used for HRAs and environmental risk as- sessments required by EPA ( 1 998a). 3. Verify that energetic materials encased in metal (e.g., rocket or other munitions fragments) will be hydrolyzed. a. Ascertain how well the SCWO process can handle high-solids materials (shredded dunnage). 5. Ascertain how well the SCWO system can treat hydrolysate containing large amounts of chlo- rides, sulfur, and phosphates on a continuing basis. 6. Determine erosion and corrosion behavior of the components of the SCWO system. FINDINGS Finding GA-1. Cryofracture appears to be an effective method for accessing the agent in projectiles and mor- tars and might provide an improvement over baseline disassembly in accessing gelled or crystallized agent. This remains to be demonstrated. Finding GA-2. Hydrolysis of energetics at the scales proposed by the technology provider is a relatively new operation. Chemically, it is possible to hydrolyze all of the energetic materials; however, the rate of hydrolysis is limited by the surface area and, therefore, depends on particle size. (Smaller particles are more desirable because they have a higher surface-to-volume ratio.) The proposed method of removing and hydrolyzing the energetics appears to be reasonable, but further testing 101 is required to determine the hydrolysis rates and to con- firm that throughput rates can be achieved. Finding GA-3. The rotary hydrolyzer appears to be a mature reactor configuration that is well suited for this application. Finding GA-4. Shredding of dunnage and injection of the slurry directly into a SCWO system is a new and unproven process. While General Atomics claims to have developed a proprietary pump capable of pump- ing the slurry at high pressures, but it has not been tested under the intense solids loading anticipated. Fur- thermore, the injection of large amounts of solid mate- rial, including wood shreds, cut-up nails, and complex organic materials, such as pentachlorophenol and other wood preservatives, into the SCWO system has not been demonstrated. Considering the difficulty SCWO reactors have encountered with deposition of solids when liquids are treated, the committee believes that this application of SCWO may encounter significant difficulties. (At the time of this writing, processing of solids with SCWO was being performed as part of the ACWA demonstrations.) Finding GA-5. All of the findings in the NRC report, Using Supercritical Water Oxidation to Treat Hydroly- sate from VX Neutralization, apply to the General Atomics system. Finding GA-6. The crystallization and evaporation operations have not been tested for this application. Although these are conventional technologies and are expected to work effectively, testing will be necessary. Finding GA-7. No hold-test-release facilities are pro- vided for gases from the hydrolysis reactors or the SCWO reactors. These gases will be scrubbed using activated carbon prior to release.
