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APPENDIX CBaseline Disassembly Process The baseline demilitarization system utilizes incin- eration to destroy chemical agents and energetic mate- rials. The Army has spent considerable time and effort to develop processes for disassembling the chemical weapons prior to incineration. Many of these processes are not "incineration-specific," that is, they dismantle the munitions but do not prepare the dismantled pieces specifically for incineration. Thus, these processes could potentially be used as part of alternative disposal technologies (other than incineration). Because several of the technology providers have incorporated the baseline disassembly process into their proposed technology packages (with some modifica- tions), the committee included this description of the overall baseline disassembly process. The storage of assembled chemical weapons is discussed first to pro- vide background on packing configurations. Then, the procedures used to bring munitions to the chemical demilitarization facility (CDF) from the storage area and prepare them for disassembly are described. Next, the actual disassembly of each type of munition (rockets; projectiles and mortars; and land mines) is explained. This is followed by a discussion of the special treat- ment required for munitions that leak during storage or transport. Finally, some of the problems encountered during baseline disassembly are described. Note that the baseline process handles all types of munitions, but only one type of munition is treated at a time. iBaseline disassembly is often referred to loosely as "reverse assembly" because the disassembly of projectiles, in general, reverses the steps used in their assembly. This description is not accurate for other munitions (e.g., M55 rockets), which are not reverse assembled. Therefore, the term reverse assembly is not used in this report to describe the overall baseline disassembly process. 197 STORAGE OF MUNITIONS Assembled chemical weapons are stored on wooden pallets stacked in igloos protective structures made of reinforced concrete. The pallet configurations vary for different types of munitions. M55 rockets, inside their fiberglass shipping and firing tubes, are stored 15 to a pallet in a 3 x 5 geometry. M23 land mines are stored in 16-gallon steel drums, three mines per drum, 12 drums per pallet. Projectiles and mortars range from eight to 24 munitions per pallet, depending on the size of the rounds. The igloos are monitored for airborne chemical agent on a regular basis, and a small but significant number of munitions have been found to leak over time. Generally, these are vapor-phase leaks, but leaks of liq- uid agent have also occurred. When munitions that leak (called leakers) are identified, they are placed in pro- tective containers (called overpacks), which act as a barrier to further leaks to the external environment. Leaker mines are overpacked in plastic and reloaded into drums. Leaker rockets, projectiles, and mortars are placed inside thick steel overpacks that are then repalletized for subsequent storage. The handling and disassembly of leaker mines is essentially identical to the handling of nonleaker mines because (1) the overpack is not extensive and (2) mine processing can be easily modified to accommodate the removal of the overpack. In contrast, the handling and disassembly of leaker rockets, projectiles, and mortars is somewhat different than for nonleakers (described in the section "Processing of Overpacked Munitions"~. The following description applies to nonleaker assembled chemical weapons.
198 ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS TRANSPORT AN D HAN DLI NG PRIOR TO DISASSEMBLY At the beginning of the disposal process, palletized munitions are removed from the storage igloo using a forklift and loaded into a cylindrical steel vessel known as an on-site container (ONC). Once the munitions are inside, the ONC is sealed to contain vapor leaks during transportation. A truck then takes the ONC from the storage area to the CDF. Inside the CDF, the ONC is delivered to the unpack area, where it is sampled for agent contamination prior to opening. If agent is de- tected, then the ONC is not opened but is instead pro- cessed as described in the section "Processing of Mu- nitions That Leak During Transport." If no agent is detected, the ONC is opened, and the munitions are removed. The munitions are then manually separated from their packaging materials. This process is quite straightforward for projectiles, mortars, and M55 rock- ets, which are simply removed from their pallets. Rock- ets are not removed from their fiberglass shipping/ firing (S/F) tubes. The unpacking process for M23 land mines is more involved. First, the mine drums are removed from the pallet. Then, individual drums (containing three mines with detached fuzes and activators) are conveyed to the mine glovebox using a forklift and mechanical lift. The mine glovebox is an enclosed space that forms a bound- ary between the unpack area and the explosion-con- tainment vestibule (ECV). Inside the glovebox, the drums are unpacked manually. Arming plugs are manu- ally removed from the mines and, along with fuzes and activators, are placed into a "fuze box" identical in size and shape to a mine casing. Once the unpack operations have been completed, the munitions (and the mine fuze boxes) are placed, one at a time, on conveyors. Rockets are oriented nose first; a special indexing ring located on the S/F tube is used by the loading machine to ensure this orientation. In contrast, projectiles are sent to the ECV base-first. The conveyors transport the munitions into the ECV and finally into the explosion-containment room (ECR), where the disassembly process begins. The ECR is separated from the ECV by blast gates and is designed to contain the effects of accidental explosions during the processing of explosively-configured munitions. Once the munitions enter the ECR, all disassembly operations take place remotely via mechanical systems. DISASSEMBLY OF M55 ROCKETS The disassembly process for the M55 rocket is shown schematically in Figure C-1. Once in the ECR, the rocket (in its S/F tube) is conveyed to the punch and drain station of the rocket-shear machine, which first drains the agent from the rocket by punching holes through the exterior of the S/F tube and the rocket. The agent drains by gravity and is pumped to an agent stor- age tank. Design requirements call for at least 95 per- cent of the agent to be drained from the rocket. When draining is complete, the rocket moves via conveyor to the shear station of the rocket-shear ma- chine, where it is cut into eight pieces by a hydrauli- cally-driven guillotine. A combination of water and caustic spray cools the shearing blade during the cut- ting operation. The first cut separates the fuze from the rest of the rocket, and the other cuts break up the burster and propellant. The sheared rocket pieces drop into a hopper and are fed into the deactivation furnace system where the metal parts are decontaminated and the re- sidual agent and energetics are destroyed. To avoid potential detonations, the feed is controlled so the fuze cannot be in the same furnace section as the burster or propellant segments. The baseline rocket disassembly system described above produces two material exit streams: (1) liquid chemical agent; and (2) sheared rocket pieces contain- ing metal, residual agent, burster energetics, intact fuzes, propellant, and fiberglass from the S/F tube. DISASSEMBLY OF PROJECTILES AND MORTARS Figure C-2 shows the disassembly process for pro- jectiles and mortars. Inside the ECR, the projectile (or mortar) is conveyed to the projectile/mortar disassem- bly machine, which removes the explosive components from the munition in three steps: (1) the fuze and booster (or lifting plug) are unscrewed from the shell using a hydraulic chuck at the nose-closure removal station, (2) the fuze well cup is unscrewed using a hy- draulically-driven collet at the miscellaneous parts-re- moval station, and (3) the burster is removed using high-pressure air at the burster-removal station. Burst- ers are subsequently sheared into pieces by the burster size-reduction machine, a modified version of the rocket-shear machine. The fuze, booster, and sheared
APPENDIX C Unpack area Rocket metering table \ Explosion , containment; . vestibule ' /~ Pallet of 15 M55 rockets in firing tubes FIGURE C-1 Baseline disassembly of MSS rockets. I Explosion-containment room 1 l I Explosion- containment vestibule 1 l Unpack area FIGURE C-2 Baseline disassembly of projectiles/mortars. 199 Explosion-containment room Rocket-shear machine . ~ Agent drain pipe Munition processing bay Feed chute for /sheared rocket pieces ~To deactivation To agent furnace system storage tank To metal parts furnace Multipurpose demilitarization machine ~ ~ To agent storage tank Projectile/mortar disassembly machine - nose-closure removal station - miscellaneous parts-removal station - burster removal station To deactivation furnace system
200 ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS burster pieces are then fed to the deactivation furnace system for incineration. The munition, with its explosives removed but its agent load still in place, then exits the ECR. Using con- veyors and pick-and-place robots, the munition is trans- ported to the munitions processing bay, where it is loaded into the multipurpose demilitarization machine. At the pull-and-drain station of this machine, a collet is inserted into the projectile, and the burster well is ex- tracted. Some burster wells are welded in place, so the multipurpose demilitarization machine also has a bore station for milling out the weld or the entire well, as necessary. Once the burster well is removed (or milled out), a drain tube is inserted into the shell body, and the agent is pumped from the munition, through a strainer, and into an agent storage tank. Design requirements call for at least 95 percent of the agent to be drained from the projectile or mortar. Following draining, the burster well is crimped (to prevent reseating) and placed back into the munition body. The munition then moves on to the metal-parts furnace for thermal decon- tamination to a 5X condition. Explosion-contai n ment vestibule Glovebox Explosion containment room ~8 j) Mine Mine conveyor If) Air: ~,~ Container with 3 mines FIGURE C-3 Baseline disassembly of land mines. The baseline projectile/mortar disassembly process produces three material exit streams: (1) liquid chemi- cal agent; (2) energetic components, including sheared burster pieces, intact fuzes, and supplementary charges; and (3) metal munition bodies containing some residual agent but no energetics. DISASSEMBLY OF M23 LAND MINES The process for disassembling land mines is shown in Figure C-3. In the ECR, the mine is transported to the mine machine, which is precisely oriented to avoid the explosive components, and is punched through its side. At least 95 percent of the chemical agent is drained and pumped to a holding tank. The mine is then moved to the booster push-out station, where the central booster is removed. The mine body and booster are fed separately to the deactivation furnace system where the metal parts are decontaminated and the re- sidual agent and energetics are destroyed. Mine fuze boxes that enter the ECR are dumped di- rectly into the deactivation furnace system, and the To agent storage tank _' - Push-out station al / To deactivation furnace system ~~ Dunnage to dunnage incinerator; drums to metal-parts furnace
APPENDIX C fuzes, activators, and arming plugs are destroyed. A magnet is used to differentiate between the mines and the plastic fuze boxes. Empty mine drums, unloaded in the mine glovebox, are sent to the metal-parts furnace for thermal decontamination. The mine disassembly process yields five material exit streams: (1) liquid chemical agent; (2) boosters; (3) metal mine bodies containing energetics and some residual agent; (4) plastic fuze boxes containing intact fuzes, activators, and arming plugs; and (5) steel mine drums. DISSASSEMBLY OF OVERPACKED MUNITIONS Leakers (rockets, projectiles, and mortars) that have been overpacked require special processing because of the increased risk of agent contamination. Like non- leakers, overpacked munitions are stored on pallets. Therefore, the procedures for removing them from an igloo and transporting them to the CDF are identical. Because of the overpacks, however, the machines nor- mally used to load the rockets, projectiles, and mortars onto the standard transport conveyors cannot be used. Instead, the entire pallet of overpacked leakers is loaded manually onto a bypass conveyor in the unpack area and conveyed through an airlock into the ECV. There, operators in demilitarization protective ensemble (DPE) suits manually unpack the pallet, remove the rockets, projectiles, or mortars from their overpacks, and load the munitions onto the conveyors to the ECR. These munitions are unpacked in the ECV rather than in the unpack area to ensure agent containment. Once the leakers enter the ECR, the disassembly steps are identical to those already described for nonleakers. DISASSEMBLY OF MUNITIONS THAT LEAK DURING TRANSPORT The act of transporting munitions from the storage area to the CDF may cause some munitions to leak. These munitions are referred to as leaking munitions, as opposed to leakers, which have leaked during stor- age and have been overpacked. To identify leaking munitions, the internal atmosphere of the ONC is moni- tored prior to opening it in the unpack area. If agent is 201 toxic maintenance area. This area is a "Level A" area, which means that liquid and airborne agent contamina tion is expected, and operators wear DPE suits. Thus, the ONC can be opened safely in this area. After opening, the pallets are removed, and the ONC and the exterior of the munitions/pallets are decontami nated using decontamination solution. The pallet is then loaded onto a special tray and conveyed backwards through the facility via the processing conveyors. This means that the pallet is taken from the toxic mainte nance area (on the first floor of the CDF) up to the ECV (on the second floor of the CDF), traveling oppo site to the "normal" conveyor direction for nonleaking munitions. When the pallet reaches the ECV, operators in DPE suits manually unpack it and load the muni tions onto the conveyor to the ECR. Once the leaking munitions enter the ECR, the disassembly steps are identical to those already described for nonleaking munitions. PROBLEMS ENCOUNTERED DURING BASLINE DISASSEMBLY At the Johnston Atoll (chemical Agent Disposal Sys tem (JACADS) in 1994, an M55 rocket burster initi ated during shearing (SAIC, 1996). The explosion con tainment functioned as designed, and no agent was released from the facility. However, damage to the dis assembly machines was extensive. The system opera tion was subsequently modified to ensure that water sprays were irrigating the cutting zone during all shear ing operations. During operational verification testing at JACADS, the multipurpose demilitarization machines (used to pull the burster wells and drain the agent from projec tiles and mortars) were found to be among the least reliable of the baseline equipment. They required a large number of toxic-area entries (and even continu ous manning) by personnel in DPEs (Mitre, 1993). Subsequent modifications have improved their reliabil ity, but quantitative data on the degree of improvement were not available. Some difficulties have also been encountered in un screwing the nose closures on projectiles. Apparently, the pitch on the nose closure threads varies, and the detected, the ONC is conveyed outside the facility and projectile/mortar disassembly machines were some taken, via a separate entrance, into an area called the times unable to unscrew the nose closures. Most of the
202 ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS problems with projectile/mortar disassembly were solved by making slight modifications to the baseline disassembly equipment; however, as of 1996, between 5.1 and 8.6 percent of the projectiles processed were rejected because of some failure in the disassembly process (PMCD, 1997). (The percentage varied with the type of projectile. ) Currently, JACADS is processing mustard-filled 4.2-inch mortars. The agent in these mortars has be- come very thick and cannot be drained using the baseline suction approach. Therefore, after the agent cavity is opened, these rounds are being introduced to the metal-parts furnace at a reduced rate. The agent volatilizes from the mortar in the furnace and is ther- mally destroyed. JACADS is currently investigating a modification to its environmental permit to allow more agent per tray of mortars into the metal-parts furnace thus, increasing the throughput rates. REFERENCES Mitre. 1993. Summary Evaluation of the Johnston Atoll Chemical Agent Disposal System: Operational Verification Testing. MTR93W0000036, May 1993. McLean, Va.: Mitre Corporation. PMCD (Program Manager for Chemical Demilitarization). 1997. Presentation by PMCD representatives from JACADS to the Committee on Review and Evaluation of the Army Chemical Stockpile Disposal Program. Honolulu, Hawaii. June 23, 1997. SAIC (Science Applications International Corporation). 1996. Tooele Chemical Agent Disposal Facility Quantitative Risk Assessment. SAIC-96/2600, December 1996. Abingdon, Md.: Science Applications International Corporation.
