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ACWA Program: First-of-a-kind Equipment for a One-of-a-kind Mission

The U.S. Army Element, Assembled Chemical Weapons Alternatives program

Tasked with a one-of-a-kind mission to destroy chemical weapons using means other than the baseline incineration method, the U.S. Army Element, Assembled Chemical Weapons Alternatives (ACWA) program is developing, testing, fabricating, and installing First-of-a-Kind (FOAK) equipment for its two project sites in Colorado and Kentucky.

ACWA is responsible for destroying 10 percent of the stockpile of chemical weapons in the United States. About 8 percent of those are stored at the Pueblo Chemical Depot in Colorado, with the remaining 2 percent stored at Blue Grass Army Depot in Kentucky.

Although the U.S. Army Chemical Materials Agency (CMA) is responsible for safe storage of the nation’s entire stockpile of chemical weapons, as well as the destruction of 90 percent of the original stockpile, Congress established ACWA in 1996 to explore alternative destruction technologies to incineration. In 2002, the program became responsible for the destruction of the Colorado and Kentucky stockpiles.

“That technology program [incineration] was based upon assessments that we had performed that said incineration really provided a holistic approach to getting rid of the chemical weapons: the agent, the energetics or explosives, as well as thermally decontaminating the metal bodies and disposing of any exposed secondary waste,” explained Kevin Flamm, ACWA program manager and former program manager for the Elimination of Chemical Weapons within CMA.

“However, our view of incineration was not shared by all of the stakeholders in the different states where the stockpiles were located. Particularly two sites – one in Kentucky and one in Colorado – were really opposed to using incineration.”

In 2002, the Department of Defense selected neutralization followed by biotreatment as the destruction technology for the stockpile in Colorado, and in 2003 neutralization followed by Supercritical Water Oxidation (SCWO) was selected for stockpile destruction in Kentucky. The neutralization step of each process destroys the agent, which produces a byproduct called hydrolysate.

“What we found is that biotreatment lent itself very readily to the further treatment of the mustard-based hydrolysate, and since Pueblo only has mustard-filled chemical weapons, that worked very well,” Flamm explained. “We found that the phosphorus in the hydrolysate from the nerve agents didn’t lend itself to biotreatment as readily as the mustard hydrolysate did. SCWO is a more robust process, as it was better able to handle the hydrolysate from not only mustard, but also the nerve agents GB and VX.”

As the more costly of the two technologies, SCWO was only selected for the Kentucky stockpile, which consists of 523 tons of GB and VX nerve agents, and mustard agent (both HD and HT), in rockets and projectiles. Biotreatment will be used in Colorado, which has 2,611 tons of mustard agent in projectiles and cartridges.

In 2002, Bechtel Pueblo was selected as the systems contractor to design, construct, systemize, pilot test, operate, and close the Pueblo Chemical Agent-Destruction Pilot Plant (PCAPP). Subsequently, Bechtel Parsons Blue Grass was selected in 2003 as the systems contractor responsible for all of the project phases at the Blue Grass Chemical Agent-Destruction Pilot Plant (BGCAPP).

“At our project [PCAPP], we’re just dealing with mustard agent, but our challenge is the number of munitions that we have to handle,” Paul Henry, Bechtel Pueblo project manager, said. “We have a large volume of munitions – 780,000 rounds. Blue Grass has a smaller number [101,000], but the complexity is the multiple types of agent that they have to dispose of.”

However, both plants must deal with the same critical challenge of accessing the agent in order to neutralize it. As this destruction technology has never been employed exactly in this manner, and the necessary equipment is not available for purchase ready to use, ACWA established its First-of-a-Kind equipment program.

“We started with something basic and then added components,” said Walton Levi, deputy site project manager for PCAPP, as he discussed the FOAK program. “For example, the Munitions Treatment Unit came from the automotive industry. They use it for forming sheet metal. We were able to take that technology and have them modify it for our use so we could run our mortars and projectiles through it.

“It’s called FOAK because we’re really the first ones to use that technology in this format, and then test it and make sure it works at the various vendors, meets our criteria, has the throughput, maintenance issues, and compatibility.”

The FOAK equipment at PCAPP includes:

  • Linear Projectile/Mortar Disassembly (LPMD), fabricated by Wright Industries in Nashville, Tenn.
  • Munitions Washout System (MWS) and Cavity Access Machine (CAM), fabricated by Parsons in Pasco, Wash.
  • Munitions Treatment Unit (MTU), fabricated by Abbott Furnace in St. Marys, Pa.

At PCAPP, the munitions will go through a disassembly process to separate the explosive components, or energetics, from the munition body using the LPMD machine in an Explosive Containment Room.

This machine will allow workers to remove the energetics from the munitions remotely, Henry explained.

The LPMD is a robot that is also similar to what is used in auto manufacturing facilities. At the baseline incineration facilities, a similar technique was used with a Projectile Mortar Disassembly machine, which moved the munitions around a circular table to various equipment stations.

Lessons learned indicated that the rotating table was something of a maintenance nightmare and ACWA decided to replace it with a six-axis industrial robot. The circular concept was redesigned so that the equipment stations will now be lined up and the LPMD will move the munitions from station to station in a straight line.

After the explosive components have been removed, the energetic-free munitions are transported to the Agent Processing Building, where they will go through the Munitions Washout System, which includes the CAM.

In the MWS, a CAM will access the projectile agent cavity by collapsing the burster well with a hydraulic ram, allowing the agent to drain. The ram will retract to a wash position and the munition will begin to rotate. High-pressure warm water will be used to flush agent liquids and residues from the munition body.

While a somewhat simplistic approach to removing the agent from the munition bodies, the MWS truly is a FOAK piece of equipment that has streamlined the process, Flamm said. The way agent was removed from munitions at the baseline plants was by inserting a metal bar in the burster well of upright munitions, with the nose at top, extracting the burster well, then inserting a siphon tube to pump out all of the agent.

testing of Linear Projectile Mortar Disassembly system

Colorado stakeholders view the testing of the Linear Projectile Mortar Disassembly system at the Anniston Chemical Agent Disposal Facility. U.S. Army photo

Since some of the mustard agent tends to solidify, the MWS allows gravity to drain out the agent by inverting the munitions and then using a high-pressure water spray to remove any thickened or solidified agent.

Once the agent is collected, the neutralization process begins inside the Agent Neutralization Reactor, with the introduction of hot water. After about 30 minutes of vigorous agitation, sodium hydroxide, commonly known as caustic, is added.

“The caustic is added to balance the pH so that when it goes to the next process the microbes will be able to digest it,” explained Jack Fahrion, mechanical engineer at PCAPP. “Otherwise it will be too acidic for them.”

Following neutralization, the biotreatment phase begins with the hydrolysate pumped into storage tanks with microbes that will digest it and break it down further. The remaining byproduct is a brine solution, which will be processed through the Brine Reduction System where an evaporator will collect the water to be reused at the plant.

Finally, in order to ensure that the empty munitions bodies are completely decontaminated before they are recycled, they go through the Munitions Treatment Unit that will thermally treat them at 1,000 degrees Fahrenheit for 15 minutes.

With the implementation of FOAK equipment, the development of FOAK testing has become a necessity.

Henry explained that developing the criteria to test the FOAK equipment has been a collaborative process involving the government, government contractors, systems contractor, and vendors.

“We establish, through a collaborative effort, criteria to complete testing to deem that the equipment is ready,” he said. “We’ve been testing in some form or fashion since the beginning of the project. By doing this in an integrated fashion it streamlines the process.”

Although construction is just over 50 percent complete at PCAPP, the FOAK equipment program is already resulting in project milestones ranging from testing to installation of equipment.

“In the last year, we’ve been able to complete the FOAK testing on all of our process units and we’re into production and manufacturing,” Henry said. “Meaning that these are the units that go in; plant-ready equipment. We’ve been fabricating the plant-ready equipment. We’ve received the MTUs and we’ll receive the MWS in August [2010], followed by the LPMD machines.

“The MTU is complete and installed in the facility. The MWS – we’ve completed all the FOAK testing, so the FOAK scope of the work is done. We’re into the production, fabrication, and testing of the process lines.”

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Nicole Heaton served for four years as a U.S. Air Force Public Affairs officer and...