Defense Enviornment Alert
October 8, 2002

NRC SAYS HYDROLYSIS CAN EFFECTIVELY DESTROY CHEMICAL WEAPONS

A new report by a National Research Council (NRC) panel finds that technologies employing hydrolysis can effectively destroy the assembled chemical weapons stockpiled in Kentucky, although the experts raise concerns about the lack of maturity for technologies proposed to handle the secondary waste streams from weapons disposal.

"The reverse assembly of munitions, followed by water or caustic hydrolysis of nerve or mustard agents and associated energetic materials, is a mature, safe, and effective method for initial treatment of the chemical weapons stored at Blue Grass Army Depot. It is ready for immediate implementation for the neutralization of energetics and agents," the report says. The panel adds, however, that "the resulting hazardous [waste] streams must be treated further before they are released to the environment." But it says that the hydrolysis could begin before the secondary treatment technology is chosen.

Citizens who oppose incinerating chemical weapons are hailing the report's findings. "This report is the piece of the equation that we've all been waiting for as we move forward toward safe disposal," Craig Williams, director of the Kentucky-based Chemical Weapons Working Group (CWWG), said in a Sept. 26 statement. CWWG is a national coalition of organizations from chemical weapons storage sites that opposes incineration.

I Earlier this year, a governor- appointed citizens advisory commission and Kentucky's congressional delegation endorsed the use of a non-incineration technology to destroy the Blue Grass stockpile (Defense Environment Alert, June 18, p 8, and July 16, p 5). The Army is in the midst of choosing which destruction technology it will use at the site, with a final decision expected early next year. "Now we have the science of the NRC to back up our position. It's a big step," Williams said.

NRC's findings are detailed in a report titled Analysis of Engineering Design Studiesfor Demilitarization of Assembled Chemical Weapons at Blue Grass Arm - y Depot, and in a follow-up Sept. 25 "letter report" that addresses some tests not yet completed when the panel wrote the larger report.

In its main report, the NRC panel says that the secondary waste streams are not unique to chemical weapons and could be treated at off-site locations, something that "would simplify the overall technology" and eliminate the need for trying to integrate secondary treatment technologies into the whole system. "It might also simplify design requirements to meet safety concerns," the report says.

The committee reiterates its belief that hydrolysis can be used to destroy safely both chemical agent and energetics, "Provided that lead-containing propellants are not processed with tetrytol until the possibility of lead picrate formation can be eliminated." The report says the fate of lead during energetics hydrolysis in the presence of picrate is not understood, and until more information is obtained, "the possibility of solid lead picrate formation cannot be dismissed." But processing lead-based propellants separately from tetryl and tetrytol would eliminate this possibility.

Three of the panel's findings relate specifically to the individual technologies examined: General Atomics' Total Solution (GATS) process, which uses supercritical water oxidation (SCWO) to treat hydrolysate; Eco Logic's process using hydrolysis followed by transpiring- wall SCWO and gas-phase chemical reduction; and AEA's SILVER 11 process using mediated electrochemical oxidation. The SILVER 11 process does not rely on hydrolysis.

The GATS SCWO process is the most mature, the report says, and "construction and testing of a full-scale reactor to treat agent hydrolysate is the next logical step," the report says. The panel expresses some concern over the level of maintenance required for the system and possible problems associated with the extent of scale-up needed for a SCWO reactor, but NRC says "the level of maintenance estimated by General Atomics for the Blue Grass application is manageable by well-trained operators and maintenance personnel."

The committee says the Eco Logic system could be an effective and safe means to destroy the assembled chemical weapons, but stable operations have not yet been demonstrated. Specifically, during testing, the system exhibited frequent spiking in hydrocarbon and carbon monoxide concentrations in the offgas, something that must be resolved before implementation, the report says. The follow-up letter report says that Eco Logic's partner, Foster Wheeler, has provided several explanations for the spiking in hydrocarbon and carbon monoxide levels, and has made changes that appear to have reduced the severity of the spiking but not eliminated it. "Based on its members' experience, the committee believes that these spikes are symptoms of an underlying instability that is not yet understood," and "Foster Wheeler should present convincing evidence that it has identified the root cause or causes of the spiking problem before scaling up the design" of the transpiring wall SCWO reactor, the letter report says. This spiking problem may affect permitting for the SCWO process, and consideration should be given to establishing a performance standard for these emissions from any SCWO reactor system selected for implementation at Blue Grass, the committee says.

NRC also addresses corrosion issues connected with Eco Logic's SCWO process. In evaluating results from the SCWO reactor, the letter report says that significant corrosion of the lower liner was experienced during testing on mustard hydrolysate but not during testing on the sarin and VX hydrolysates. "This may be due to chlorine which is present in the [mustard] hydrolysate but not in the [sarin] and VX hydrolysates," the letter report says, adding that while the Blue Grass stockpile has lower amounts of mustard compared with the other two agents, increased maintenance will be required during the mustard campaign. And because all SCWO testing experience to date, regardless of the type of SCWO used, has shown challenges with corrosion and material durability, "the committee believes that use of the SCWO process will require that the operator have an aggressive monitoring program in place to ensure that planned completion schedules are not severely compromised by higher than expected maintenance and repairs."

In its main report, NRC says SILVER II "could eventually destroy" the Blue Grass weapons, but "the immaturity of a significant number of processes in this electrochemical destruction technology could threaten [the military's] achievement of its objectives for weapons destruction." The panel adds, "There is also concern that the ever-increasing complexity and frequent configuration changes that have occurred in the AEA technology package to date are indicative of the immaturity of the process."

In the letter report, the panel notes that additional tests show SILVER II is capable of destroying tetrytol, a component of energetics, but "the committee continues to believe the complexity of the full-scale plant still poses major maturation challenges that might not allow consistent achievement of similarly reliable overall performance."

Finally, NRC says in the main report that because none of the technology packages have ever been operated as a total integrated system, "a prolonged period of systemization will be necessary to resolve integration issues for the selected technology as they arise, even for apparently straightforward unit operations."