The first Static Detonation Chamber component was placed on its concrete pad Oct. 31 at the Pueblo Chemical Agent-Destruction Pilot Plant, marking the start of assembly for the first of three units that will augment the main plant’s automated processes.

“The team has done a fantastic job in preparation to set the equipment safely and efficiently,” said Matt Crookshanks, SDC project manager. “This was a major effort by Assembled Chemical Weapons Alternatives, Colorado Department of Public Health and Environment, Pueblo Chemical Depot and the project team to get to this important milestone. It is a major step in going vertical on the site which will open up new work fronts to continue to progress the project.”

The Pueblo plant received temporary authorizations from the state of Colorado and Pueblo County to begin SDC assembly in late October. Before that, work had been limited to infrastructure and concrete pad placement at the site. The first SDC components arrived by convoy in August.

Ken Harrawood, project manager, Bechtel Pueblo Team, said at the Oct. 30 Colorado Chemical Demilitarization Citizens’ Advisory Commission meeting in Pueblo that staff was being trained now to allow the unit to be systemized as soon as possible.

One SDC is already in use at Kentucky’s Blue Grass Chemical Agent-Destruction Pilot Plant, going online in summer 2019, with a second unit in development there. Pueblo staff is benefiting from lessons learned at the Richmond, Kentucky, facility, and the two facilities stay in regular contact.

Chemical agent-filled munitions – containing mustard agent at the Pueblo plant – will be placed in a carrier, conveyed to the top of the SDC vessel and fed into the electrically heated detonation chamber. High temperatures (approximately 1,100 degrees Fahrenheit) detonate or deflagrate the munition, and the chemical agents are destroyed by thermal decomposition.

Gases generated from this process are captured by an off-gas treatment system that includes a thermal oxidizer to convert carbon monoxide and hydrogen to carbon dioxide, water and acid gases (hydrochloric and sulfuric). Gases from the thermal oxidizer are cooled and filtered to remove any contaminants.

Some munitions from the U.S. Army Pueblo Chemical Depot stockpile, such as 4.2-inch mortar rounds, cannot be safely processed in the main plant and will be disposed of in the SDCs.

That makes the three SDC units essential to meeting the Congressionally mandated deadline of 2023 to meet international treaty obligations to destroy the United States’ remaining chemical weapons, said Nicholas Stamatakis III, deputy program executive officer, ACWA. He was addressing the Citizens’ Advisory Commission at its October meeting.