Executive Summary

The Program Manager for Assembled Chemical Weapons Assessment (PMACWA) of the Department of Defense (DOD) requested the National Research Council (NRC) to assess the engineering design studies (EDSs) developed by Parsons/Honeywell and General Atomics for a chemical demilitarization facility to completely dispose of the assembled chemical weapons at the Pueblo Chemical Depot in Pueblo, Colorado. To accomplish the task, the NRC formed the Committee on Review and Evaluation of Alternative Technologies for Demilitarization of Assembled Chemical Weapons: Phase II (ACW II Committee). This report presents the results of the committee’s scientific and technical assessment, which will assist the Office of the Secretary of Defense in selecting the technology package for destroying the chemical munitions at Pueblo. The Record of Decision (ROD) for selecting the technology package is expected in the second half of 2001.

The committee evaluated the engineering design packages proposed by the technology providers and the associated experimental studies that were performed to validate unproven unit operations. A significant part of the testing program involved expanding the technology base for the hydrolysis of energetic materials associated with assembled weapons. This process was a concern expressed by the Committee on Review and Evaluation of Alternative Technologies for Demilitarization of Assembled Chemical Weapons (ACW I Committee) in its original report in 1999 (NRC, 1999). The present study took place as the experimental studies were in progress. In some cases, tests for some of the supporting unit operations were not completed in time for the committee to incorporate results into its evaluation. In those cases, the committee identified and discussed potential problem areas in these operations. Based on its expertise and its aggressive data-gathering activities, the committee was able to conduct a comprehensive review of the test data that had been completed for the overall system design.

This executive summary is divided into four sections. The first section provides historical background for the DOD’s program for chemical demilitarization and the NRC’s involvement. The next section gives the statement of task for the ACW II Committee’s studies. The third section briefly describes the technologies and test programs assessed in this report, and the final section presents the committee’s general findings. Detailed findings and recommendations found in the chapters relating to the individual technologies are not repeated here, but they may be found at the end of each chapter.

HISTORICAL BACKGROUND

The U.S. Army is in the process of destroying the U.S. stockpile of aging chemical weapons, which is stored at eight locations in the continental United States and on Johnston Atoll in the Pacific Ocean. The deadline for completing the destruction of these weapons, as specified by the Chemical Weapons Convention (CWC) international treaty, is April 29, 2007. Originally, the Army selected incineration as the preferred baseline destruction technology, and it currently operates two incineration facilities—one on Johnston Atoll and one at the Deseret Chemical Depot near Tooele, Utah. The Johnston Atoll Chemical Agent Disposal System completed destruction of the stockpile on Johnston Island in late 2000, and plans for closure of the facility are under way.1 Similar baseline incineration system facilities were planned for all of the remaining storage sites. However, incineration has met with public and political opposition. In response to this opposition, neutralization processes (based on the hydrolysis of chemical agent using either water or sodium hydroxide solution) have been developed to destroy the chemical agents stored in bulk containers at Aberdeen, Maryland, and Newport, Indiana. For the remaining sites, where

1  

The stockpile on Johnston Island comprised 2,031 tons, or 6.4 percent, of the original 31,496 tons of chemical nerve and blister (mustard) agents in the U.S. stockpile.



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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Pueblo Chemical Depot Executive Summary The Program Manager for Assembled Chemical Weapons Assessment (PMACWA) of the Department of Defense (DOD) requested the National Research Council (NRC) to assess the engineering design studies (EDSs) developed by Parsons/Honeywell and General Atomics for a chemical demilitarization facility to completely dispose of the assembled chemical weapons at the Pueblo Chemical Depot in Pueblo, Colorado. To accomplish the task, the NRC formed the Committee on Review and Evaluation of Alternative Technologies for Demilitarization of Assembled Chemical Weapons: Phase II (ACW II Committee). This report presents the results of the committee’s scientific and technical assessment, which will assist the Office of the Secretary of Defense in selecting the technology package for destroying the chemical munitions at Pueblo. The Record of Decision (ROD) for selecting the technology package is expected in the second half of 2001. The committee evaluated the engineering design packages proposed by the technology providers and the associated experimental studies that were performed to validate unproven unit operations. A significant part of the testing program involved expanding the technology base for the hydrolysis of energetic materials associated with assembled weapons. This process was a concern expressed by the Committee on Review and Evaluation of Alternative Technologies for Demilitarization of Assembled Chemical Weapons (ACW I Committee) in its original report in 1999 (NRC, 1999). The present study took place as the experimental studies were in progress. In some cases, tests for some of the supporting unit operations were not completed in time for the committee to incorporate results into its evaluation. In those cases, the committee identified and discussed potential problem areas in these operations. Based on its expertise and its aggressive data-gathering activities, the committee was able to conduct a comprehensive review of the test data that had been completed for the overall system design. This executive summary is divided into four sections. The first section provides historical background for the DOD’s program for chemical demilitarization and the NRC’s involvement. The next section gives the statement of task for the ACW II Committee’s studies. The third section briefly describes the technologies and test programs assessed in this report, and the final section presents the committee’s general findings. Detailed findings and recommendations found in the chapters relating to the individual technologies are not repeated here, but they may be found at the end of each chapter. HISTORICAL BACKGROUND The U.S. Army is in the process of destroying the U.S. stockpile of aging chemical weapons, which is stored at eight locations in the continental United States and on Johnston Atoll in the Pacific Ocean. The deadline for completing the destruction of these weapons, as specified by the Chemical Weapons Convention (CWC) international treaty, is April 29, 2007. Originally, the Army selected incineration as the preferred baseline destruction technology, and it currently operates two incineration facilities—one on Johnston Atoll and one at the Deseret Chemical Depot near Tooele, Utah. The Johnston Atoll Chemical Agent Disposal System completed destruction of the stockpile on Johnston Island in late 2000, and plans for closure of the facility are under way.1 Similar baseline incineration system facilities were planned for all of the remaining storage sites. However, incineration has met with public and political opposition. In response to this opposition, neutralization processes (based on the hydrolysis of chemical agent using either water or sodium hydroxide solution) have been developed to destroy the chemical agents stored in bulk containers at Aberdeen, Maryland, and Newport, Indiana. For the remaining sites, where 1   The stockpile on Johnston Island comprised 2,031 tons, or 6.4 percent, of the original 31,496 tons of chemical nerve and blister (mustard) agents in the U.S. stockpile.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Pueblo Chemical Depot munitions containing both chemical agent and energetic materials (i.e., assembled chemical weapons) are stored, incineration is still the planned approach for destruction. In late 1996, however, Congress enacted Public Law 104–201, which instructed DOD to “conduct an assessment of the chemical demilitarization program for destruction of assembled chemical munitions and of the alternative demilitarization technologies and processes (other than incineration) that could be used for the destruction of the lethal chemical agents that are associated with these munitions.” Another law, Public Law 104–208, required a new program manager (the Program Manager for Assembled Chemical Weapons Assessment) to “identify and demonstrate not less than two alternatives to the baseline incineration process for the demilitarization of assembled chemical munitions.” In addition, the law prohibited any obligation of funds for the construction of incineration facilities at two storage sites—Lexington/Blue Grass, Kentucky, and Pueblo, Colorado—until the demonstrations were completed and an assessment of the results had been submitted to Congress by DOD. As a result of Public Laws 104–201 and 104–208, DOD created the Assembled Chemical Weapons Assessment (ACWA) program. To ensure public involvement in the program, the PMACWA enlisted the Keystone Center—a nonprofit, neutral facilitation organization—to convene a diverse group of interested stakeholders, called the Dialogue on ACWA (or, simply, the Dialogue), who would be intimately involved in all phases of the program. The 35 members of the Dialogue include representatives of the affected communities, national citizen groups such as the Sierra Club, state regulatory agencies, affected Native American tribes, the Environmental Protection Agency (EPA), and DOD. The PMACWA established an elaborate program for evaluating and selecting technologies that would be appropriate for destroying the stockpile at Pueblo Chemical Depot and Blue Grass Chemical Depot. The selection process is described in detail in the 1999 NRC report Review and Evaluation of Alternative Technologies for the Demilitarization of Assembled Chemical Weapons. Six technology packages were originally considered for the demonstration tests. Three of these technologies underwent demonstration testing in the first round (Demonstration I) and two technology packages survived as candidates for the destruction of chemical weapons at the Pueblo Chemical Depot: those of General Atomics and Parsons/Honeywell. In Public Law 105–261 (1999), Congress mandated as follows: “The program manager for the Assembled Chemical Weapons Assessment shall continue to manage the development and testing (including demonstration and pilot-scale testing) of technologies for the destruction of lethal chemical munitions that are potential or demonstrated alternatives to the baseline incineration program.” It also directed that the Army continue its coordination with the NRC. The PMACWA subsequently initiated EDSs for the two technologies that successfully completed demonstration testing. The purpose of this EDS phase is to (1) support the development of a Request for Proposals (RFP) for a pilot facility; (2) support the certification decision of the Under Secretary of Defense for Acquisition and Technology, as directed by Public Law 105–261; and (3) support documentation required for the National Environmental Policy Act (NEPA) and the data required for a permit under the Resource Conservation and Recovery Act (RCRA). Each EDS comprises two parts: an engineering design package (EDP) and the results of experimental studies conducted to generate required data that were not obtained during the demonstration test phase. In response to Public Law 104–201, which required that DOD coordinate its efforts with the NRC in assessing alternatives to incineration, PMACWA asked the NRC to evaluate each of the seven technologies that had passed DOD’s initial screening. The ACW I Committee published its report in August 1999. That report found that the primary treatment processes could decompose the chemical agents with destruction efficiencies of 99.9999. However, major concerns for each technology package remained, including the adequacy of secondary treatment of agent hydrolysates and the primary and secondary treatment of energetic materials contained in the chemical weapons. A supplemental report, requested by the PMACWA to evaluate the actual demonstration tests for the three technologies that were considered to warrant further investigation, was published in February 2000. Two of the technologies, those of General Atomics and Parsons/Honeywell, were considered ready to proceed to an engineering design phase. Upon completion of the supplemental report, the ACW I Committee was dissolved. Subsequently, under the continuing mandate from Congress, the PMACWA requested that the NRC form a second committee (the ACW II Committee) to evaluate the EDPs and related tests for the engineering design studies for the Pueblo and Blue Grass Depots and to examine and evaluate the Demonstration II tests of three additional technologies. STATEMENT OF TASK The statement of task for the NRC ACW II Committee is shown below. The present report is the committee’s response to Task 2 and will be produced in time to contribute to the ROD by the Office of the Secretary of Defense on a technology selection for the Pueblo site. The latter will occur following satisfaction of NEPA requirements. At the request of the DoD’s Program Manager for Assembled Chemical Weapons Assessment (PMACWA), the NRC Committee on Review and Evaluation of Alternative Technologies for Demilitarization of Assembled Chemical Weapons will provide independent scientific and technical assessment of the Assembled Chemical Weapons Assessment (ACWA) program. This effort will be divided into three tasks. In each case, the NRC was asked to perform a techni-

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Pueblo Chemical Depot cal assessment that did not include programmatic (cost and schedule) considerations. Task 1 To accomplish the first task, the NRC will review and evaluate the results of demonstrations for three alternative technologies for destruction of assembled chemical weapons located at U.S. chemical weapons storage sites. The alternative technologies to undergo demonstration testing are: the AEA Technologies electrochemical oxidation technology, the Teledyne Commodore solvated electron technology, and the Foster Wheeler and Eco Logic transpiring wall supercritical water oxidation and gas phase chemical reduction technology. The demonstrations will be performed in the June through September 2000 timeframe. Based on receipt of the appropriate information, including: (a) the PMACWA-approved Demonstration Study Plans, (b) the demonstration test reports produced by the ACWA technology providers and the associated required responses of the providers to questions from the PMACWA, and (c) the PMACWA’s demonstration testing results database, the committee will: perform an in-depth review of the data, analyses, and results of the unit operation demonstration tests contained in the above and update as necessary the 1999 NRC report, Review and Evaluation of Alternative Technologies for Demilitarization of Assembled Chemical Weapons (the ACW report) determine if any of the AEA Technologies, Teledyne Commodore, and Foster Wheeler/Eco Logic technologies have reached a technology readiness level sufficient to proceed with implementation of a pilot-scale program produce a report for delivery to the PMACWA by July 2001 provided the demonstration test reports are made available by November 2000. (An NRC report delivered in March 2000 covered the initial three technologies selected for demonstration phase testing.) Task 2 For the second task, the NRC will assess the ACWA Engineering Design Study (EDS) phase in which General Atomics and Parsons/Honeywell (formerly Parsons/Allied Signal) will conduct test programs to gather the information required for a final engineering design package representing a chemical demilitarization facility at the Pueblo, Colorado stockpile site. The testing will be completed by September 1, 2000. Based on receipt of the appropriate information, including: (a) the PMACWA-approved EDS Plans, (b) the EDS test reports produced by General Atomics and Parsons/ Honeywell, (c) PMACWA’s EDS testing database, and (d) the vendor-supplied engineering design packages, the committee will: perform an in-depth review of the data, analyses, and results of the EDS tests assess process component designs, integration issues, and overarching technical issues pertaining to the General Atomics and the Parsons/Honeywell engineering design packages for a chemical demilitarization facility design for disposing of mustard-only munitions produce a report for delivery to the PMACWA by March 2001 provided the engineering design packages are received by October 2000. Task3 For the third task, the NRC will assess the ACWA EDS phase in which General Atomics will conduct test programs to gather the information required for a final engineering design package representing a chemical demilitarization facility at the Lexington/Blue Grass, Kentucky stockpile site. The testing will be completed by December 31, 2000. Based on receipt of the appropriate information, including: (a) the PMACWA-approved EDS Plans, (b) the EDS test reports produced by General Atomics, (c) PMACWA’s EDS testing database, and (d) the vendor-supplied engineering design package, the committee will: perform an in-depth review of the data, analyses, and results of the EDS tests assess process component designs, integration issues, and overarching technical issues pertaining to the General Atomics engineering design package for a chemical demilitarization facility design for disposing of both nerve and mustard munitions produce a report for delivery to the PMACWA by September 2001 provided the engineering design package is received by January 2001. DESCRIPTION OF THE TECHNOLOGY PACKAGES The assembled chemical weapons at Pueblo contain only mustard agent and energetic materials. The operations required for their destruction include (1) unpacking and disassembling the weapons, (2) separation of agents, energetics, and metal parts, (3) destruction of agent and energetic hydrolysates, (4) decontamination of the metal parts, (5) destruction of the dunnage, and (6) treatment and disposal of all associated solid, liquid, and gaseous by-products. For both the General Atomics and the Parsons/Honeywell design packages, the primary treatment to destroy the agent and the energetic materials is hydrolysis. However, the hydrolysis products (hydrolysates) must be further treated before the final products can be properly disposed of. For this secondary step, General Atomics proposes to use supercritical water oxidation (SCWO) and Parsons/ Honeywell proposes to use biotreatment via immobilized cell bioreactors (ICBs). Both technology packages consist of multiple unit operations that work in sequence or concurrently to carry out all aspects of chemical weapons destruction. Both processes are designed to treat agent, energetic materials, metal parts

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Pueblo Chemical Depot (including munitions bodies), dunnage (e.g., wooden pallets and packing boxes used to store munitions), and nonprocess waste (e.g., 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). Each EDP includes engineering drawings and documentation, a preliminary hazards analysis, and costs and schedule for the technology to be implemented at the Pueblo Chemical Depot. Short descriptions are given below. More detailed descriptions of the unit operations for each technology are given in Chapters 3 and 4. Figure ES-1 is a block diagram of the General Atomics technology process, which uses the acronym GATS (General Atomics total solution). The following major operations are included: A modified baseline disassembly process is used; however, cryofracture is used to open the projectile bodies to access the agent. The bodies are cooled to liquid nitrogen temperature and fractured. Then the metal parts are separated from the agent. Agents and energetics are hydrolyzed in batch reactors to form hydrolysates. Fuzes are digested in an energetics rotary hydrolyzer with caustic. Munition bodies are decontaminated to a 5X condition by using an electrically heated discharge conveyor. The dunnage is shredded and slurried. All the resulting hydrolysates and the slurried dunnage are further treated with SCWO to produce environmentally benign products. System off-gases are processed through carbon filters. The unit operations tested during the EDS phase are the dunnage shredder hydrolysis system (DSHS), the energetic rotary hydrolyzer (ERH), and the SCWO reactor. The testing of the SCWO reactor had not been completed when this report was prepared. The Parsons/Honeywell technology team uses the acronym WHEAT (water hydrolysis of explosives and agent technology) to denote its technology package for the demilitarization of assembled chemical weapons. The process is described in Figure ES-2. It consists of the following main operations: The Army’s baseline disassembly process, with modifications, is used to separate agent, energetics, and metal parts. The solid heel or sludge that remains inside the munitions casing is washed out in the projectile rotary washout machine (RWM) using recirculated wash water through high-pressure water jets. Bursters from the mortars and projectiles are fed into the burster washout machine (BWM) by a pick-and-place machine and processed in the BWMs to wash out all explosives. FIGURE ES-1 Simplified block diagram of GATS process components. Source: Adapted from General Atomics, 2000a.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Pueblo Chemical Depot FIGURE ES-2 Parsons/Honeywell WHEAT block flow diagram. Source: Adapted from Parsons, 2000a.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Pueblo Chemical Depot The energetics rotary deactivator (ERD) receives fuzes, booster cups, and miscellaneous parts, and it heats them until they are deflagrated. Agents and energetics are hydrolyzed in batch reactors to form hydrolysates. Agent and energetics hydrolysates are diluted with water, mixed with inorganic nutrients, and fed to the ICBs, which contain aerobic microorganisms that will consume most of the organic content of the hydrolysates. Biological processing, followed by evaporation/ crystallization, converts the hydrolysis products to liquids or solids acceptable for discharge to the environment or liquids acceptable for recycling. Biological treatment is done in the ICBs. Metal parts are all treated either in the batch metal parts treater (batch MPT) or the rotary metal parts treater (rotary MPT) to decontaminate metal parts to 5X. Dunnage is heat treated in the continuous steam treater (CST) to decontaminate it to 5X. Gas discharges from the plant are passed through catalytic oxidation (CATOX) units. Some of the gas streams are also passed through activated carbon filters. The ICB, the CST, the CATOX unit, and the projectile washout system were tested during EDS. However, the CST and the projectile washout operations were not finished at the time this report was prepared. The committee formed two working groups to perform in-depth evaluations of each EDP. As part of their efforts, the groups visited the EDS test sites at Aberdeen Proving Ground, Maryland; Dugway Proving Ground, Utah; and Deseret Chemical Depot, Utah. Committee members also attended PMACWA status-review meetings, which were held periodically, and a review meeting at Parsons/ Honeywell in Pasadena, California, where both Parsons/ Honeywell and General Atomics personnel described their EDPs and the results of ongoing tests. The technology providers and PMACWA staff kindly provided draft copies of reports as they were generated. The final EDPs were released in October 2000. In evaluating the general efficacy of the design plans for a chemical demilitarization facility suited to the Pueblo Chemical Depot and the readiness of each technology to go forward to the next level of pilot plant testing, the committee relied upon its knowledge of the proposed systems, available test results, aggressive data collection activities, and thorough review of the engineering design plans. GENERAL FINDINGS General findings on the EDS phase of the ACWA program for the two technology packages evaluated in this report appear below. The general findings must be considered with acknowledgment of the fact that some ACWA EDS testing was not completed in time for the committee to obtain final test results and that some process steps remain to be demonstrated on a pilot scale. Specific findings and recommendations for each technology package, as well as the PMACWA-sponsored investigations on hydrolysis of energetic materials, appear in the body of the report. The energetics hydrolysis test program is progressing at a pace satisfactory to meet the engineering requirements for construction of a disposal facility at Pueblo Chemical Depot. Issues surrounding the hydrolysis of neat tetryl, optimum granulation sizes, more complete characterization of hydrolysis products from aromatic nitro compounds, and optimum process control strategies for full-scale operations are yet to be investigated. General Finding (Pueblo) 1. Based on the results of the demonstration tests, the engineering design package, and available data, the committee believes that the Parsons/ Honeywell WHEAT technology package can provide an effective and safe means of destruction for the assembled chemical weapons stored at the Pueblo Chemical Depot. However, some of the process steps remain to be demonstrated. The Parsons/Honeywell technology process provides effective means to: disassemble munitions by a modified baseline disassembly process that removes the agent from the projectile bodies by washout destroy chemical agent HD to a 99.9999 percent destruction and removal efficiency (DRE) by hydrolysis destroy fuzes with the energetics rotary deactivator destroy energetic materials to a 99.999 percent DRE by hydrolysis in 15 weight percent hot caustic solution, provided that the following safeguards are observed: different energetic materials are not processed together precautions are taken to ensure that all emulsified TNT is completely destroyed control the very large volumes of off-gases emitted from the biotreatment plant through a CATOX unit However, the committee notes that the effectiveness of some process steps, including removal of energetics from munitions, has not been tested during the EDS. Treatment of metal parts, dunnage, and DPE suit material remains to be demonstrated. No tests are currently planned to demonstrate the efficacy of the burster washout and energetic materials size-reduction steps. The projectile washout system is currently being tested. Other remaining munition disassembly operations are very similar to those used in the baseline system and have therefore been proven. The energetics rotary

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Pueblo Chemical Depot deactivator concept appears workable but has not been demonstrated at the pilot scale. Energetics hydrolysis is relatively immature, but current testing at Holston AAP has the capability to resolve many, but not all, of these issues (see Chapter 2). The testing of the continuous steam treater for dunnage and the projectile washout system will not be complete until October 2001. Dioxins and furans are present in the off-gas from the CATOX units on the bioreactors but are below levels of regulatory concern. The batch metal parts treater for small metal parts is being tested, and preliminary data are encouraging. The carousel fixture for the rotary metal parts treater for large metal parts has not been demonstrated. The use of catalytic oxidizers for various streams is currently being tested, but sufficient test data have not been provided to the committee. Because the honeycomb structure of the CATOX unit is susceptible to plugging, proper design must be employed to prevent particulates from entering the catalyst structure. General Finding (Pueblo) 2. Based on the results of the demonstration tests, the engineering design package, and available data, the committee believes that many aspects of the General Atomics technology package can be effective and safe for the destruction of assembled chemical weapons at the Pueblo Chemical Depot. However, to achieve prolonged operability of the SCWO system as designed will require extensive maintenance. In addition, the SCWO processing of dunnage slurried in energetics hydrolysate, which constitutes the vast majority of the feedstock to be processed, remains unproven. The viability of the General Atomics technology package will depend on acceptable operability of the SCWO system. The General Atomics technology process provides effective means to: disassemble munitions by using a modified baseline disassembly process for munitions and removal of the agent from the projectile bodies by cryofracture destroy chemical agent HD to a 99.9999 percent DRE by hydrolysis destroy fuzes with the energetics rotary hydrolyzer destroy energetic materials to a 99.999 percent DRE by hydrolysis in 15 weight percent hot caustic solution, provided that the following safeguards are observed: different energetic materials are not processed together precautions are taken to ensure that all emulsified TNT is completely destroyed provide effective 5X-level decontamination for munition bodies through the use of an electrically heated discharge conveyor readily control the very low volumes of off-gases produced through activated carbon adsorption systems For dunnage, the materials are shredded and reduced in size to 1.0 mm. The slurry is then fed into the SCWO reactors to destroy all the dunnage. However, the committee has serious concerns about the SCWO system that is used to process the hydrolysates and the slurried dunnage. At the time this report was prepared, not all of the long-term processing tests had been completed. On the basis of results to date, the committee has concerns about the ability of the SCWO reactor to operate continuously for adequate lengths of time. An additional concern is the ability of the size reduction system to remove 100 percent of the tramp metal that comes with the dunnage. If the tramp metal is not removed from the dunnage, the committee believes it will clog the injectors of the SCWO system and further reduce the system’s online availability. The SCWO tests that have been performed to date, especially those involving chlorinated organic compounds such as HD hydrolysate, have consistently encountered severe corrosion of the reactor material or plugging of the reactor with salts. General Atomics proposes to solve the problem of plugging by periodically (every 22 hours of operation) reducing the pressure of the reactor to slightly below the critical point of water and flushing with clean water for 2 hours to remove the accumulated salts. The technology provider proposes to deal with the corrosion problem by inserting into the SCWO reactor a sacrificial titanium liner and shutting down at approximately every 140 hours of operation to open the reactor and replace or reverse the liner.2 In the committee’s opinion, the flushing step does not pose an unreasonable operating requirement; however, it considers the need for a liner replacement at six-day intervals to be excessively disruptive and not in keeping with sound principles of effective operation. In the full-scale system, liner replacement will require the following steps: Cooling down and depressurizing the reactor, Unbolting and removing an approximately 16-inch-diameter, several-inch-thick pressure head from the top of the reactor, Withdrawing the 12.5-inch-diameter, 19-foot-long titanium liner from the tubular SCWO reactor, Reinserting the same liner reversed end to end or a new liner, Setting the pressure gasket back into place and reattaching the gasket coolant lines, Resetting and bolting the pressure head onto the reactor, Pressure testing the SCWO reactor to assure proper head seating and sealing, and Restarting the heat-up of the system and restarting the waste feed. 2   The corrosion is restricted to the top part of the liner so each liner can be used twice by opening the reactor and reinstalling it in the reactor with the uncorroded lower part up.

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Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Pueblo Chemical Depot This appears to the committee to be a very time-consuming procedure. The experience of a number of committee members has been that large pieces of high-pressure equipment are very difficult and time consuming to seal. Tests have only been conducted with reactors 2 inches to 4 inches in diameter. The time required for this procedure at the far larger size of the full-scale SCWO unit is highly uncertain. General Atomics proposes to build duplicate SCWO reactors so that one is operating while the second is being serviced; however, the committee has reservations about whether this level of redundancy is adequate to maintain the proposed operating schedule. General Finding (Pueblo) 3. As the ACW I Committee observed, the unit operations in both the General Atomics GATS and the Parsons/Honeywell WHEAT technology packages have never been operated as total integrated processes. As a consequence, a prolonged period of systemization will be necessary for both to resolve integration issues as they arise, even for apparently straightforward unit operations. This finding continues to be valid following development of and testing for the EDS design packages for the General Atomics and Parsons/Honeywell technologies. Also, in both cases, some of the routine unit operations have not yet been designed or tested. Thus, although they appear straightforward, these unit operations could require some redesign during systemization. General Finding (Pueblo) 4. Several of the unit operations in both the General Atomics and Parsons/Honeywell processes are intended to treat process streams that are not unique to the chemical weapons stockpile and that could potentially be treated at existing off-site facilities. These streams include agent-free energetics, dunnage, brines from water recovery, and hydrolysates. Off-site treatment would simplify the overall processes and facilitate process integration by eliminating the need for further development of these unit operations. It might also simplify design requirements to meet safety concerns. All of the process streams that could potentially be treated off-site have compositions similar to waste streams routinely treated by commercial industrial waste treatment facilities and do not exhibit any unique toxicity. Thus, they could be transported by standard commercial conveyance to commercial facilities that are appropriately permitted to receive the waste.