By T'Jae Gibson, Army Research Laboratory, Public Affairs OfficeDecember 18, 2012
An expert panel recently recommended to the Defense Department that thermal and chemical technologies may present the best disposal options of the more than 69,000 Cold War-era M55 rockets containing nerve agents currently stored at the Blue Grass Army Depot.
The committee on "Disposal Options for the Rocket Motors from Nerve Agent Rockets Stored at Blue Grass Army Depot" of the Board on Army Science and Technology at the National Research Council completed its nine-month review in October. The panel teamed to offer guidance on technologies and options for the disposal of the rocket motor sections of the M55 rocket.
Dr. Brad Forch, the U.S. Army Research Laboratory senior research scientist for ballistics, said one of the committee's tasks was to look at alternate methods to dispose of separated rocket motors. He was the sole Army representative on the panel.
He said much of the committee's study addressed safety risks that can impact the disposal of the separated rocket motors, which contain approximately 20 pounds degraded M28 propellant that are now more than 50 years old.
The committee also investigated the status and maturity of disposal options for the separated rocket motors that include treatment and disposal on-site at the depot or off-site at a commercial or governmental facility; and the feasibility of recycling options for the propellant and rocket motor components and analysis of relevant safety, health, environmental and regulatory requirements.
The use of explosive destruction technologies was one recommended option. These technologies were recently integrated in demilitarization efforts at Sandia National Laboratories and at the Anniston Chemical Agent Disposal Facility. Recent studies showed that communities near those operations recognized that the safe use of explosive destruction technologies can meet state regulations, and can reduce the risk to workers and the community.
The M55 rocket is almost seven feet long, and has a warhead that contains approximately 10 pounds of chemical nerve agent. The M55 rockets will be destroyed at the Blue Grass Chemical Agent-Destruction Pilot Plant, whose construction is expected to be completed by 2017. The plant will robotically cut the rocket and separate it into the rocket warhead and the rocket motor. Plans are to destroy the rocket warhead at that facility by chemical neutralization followed by supercritical water oxidation.
"The plant is loaded with all sorts of sensors and safety equipment to destroy the chemical agents completely. Decades of research and study went into developing the process," Forch said about the Program Executive Office for Assembled Chemical Weapons Alternatives effort.
But the safety risks associated with disposing separated rocket motors are some of the biggest obstacles the Army faces, he said. Due to aging and degradation, the M28 propellant has potentially become more sensitive to shock and thermal conditions.
According to the 2012 report, "The separated rocket motors will also be more exposed to environmental conditions, such as heat and humidity, than they were as part of an assembled rocket. This could accelerate propellant degradation and increase the safety risks. Measures can be taken, however, to address the risk of accelerated propellant degradation, among them using desiccant to control humidity, and designing storage boxes so that heat dissipation is adequate. In any case, the committee believes that the separated rocket motors should be disposed of as soon as possible after rocket cutting."
Forch added that because of its solid state, opposed to the liquid found in the chemical warhead section, the rocket motor is harder to destroy.
Since the mid-1960s, the United States produced more than 400,000 M55 chemical rockets for military use, according to a U.S. Army Chemical Materials Agency fact sheet. But none of the rockets were ever used in combat so by 1981, they were declared obsolete and of no military value.
Rockets have been stockpiled within Blue Grass' enormous safe storage igloos, but when an increasing number of rocket motors are separated from their warheads during chemical destruction operations, the depot could potentially reach a point where they run out of storage, Forch said.
Forch joined ARL's predecessor organization, the Ballistic Research Laboratory, in 1985 as a National Research Council postdoctoral fellow after completing his terminal degree in physical chemistry/chemical physics. He performed research in laser spectroscopy in the areas of ignition and combustion research at BRL, and was subsequently hired as a civilian employee in 1986. He spent his nearly 30-year career working with energetic materials and ballistics, which includes concentrations in gun propellants, rocket propellants and explosives. He was named an Army Senior Research Scientist for Ballistics in 2009, and an ARL Fellow in 2010.
ARL's Dr. Rose Pesce-Rodriguez and Dr. Stephanie Piraino Haynes, both experts in solid propellant ingredient chemical and physical properties research, also contributed to this project.