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Unique YPG plant freezes, destroys old munitions
YUMA PROVING GROUND - The U.S. Army has been looking for a way to get rid of its spent munitions for years, and a disposal process called cryofracture, which has been conducted at the base since May, seems to be the best solution.
Cryofracture involves cooling the munitions in liquid nitrogen until the casing becomes brittle and can be cracked open by a hydraulic press.
"It's environmentally safe and cost effective," said Ron Jasper, mechanical engineering technician at YPG's cryofracturing plant. "It's also adaptable to all forms of munitions."
The cryofracture plant at YPG is one of two plants in the country capable of doing this type of process and currently the only one in operation.
Munitions must be disposed after testing. Prior to the the cryofracture, the traditional method of disposing of munitions has been blowing up the remains and unused ordnance at the site of the testing.
"We test ordnance out here, so after each test, we need to get rid of what's left," Jasper said. "It's kind of like cleaning up your mess."
Jasper explained that after each test has been completed, an ordnance recovery team is sent to the site to pick up all the spent munitions.
"Most of these people are retired military explosive ordnance disposal personnel," Jasper said. "They are highly-trained people."
Once all the munitions from a test have been collected, they are then brought back to the cryofracture plant, where the munitions are loaded into a tray and soaked in liquid nitrogen.
"When steel gets to about 220 to 250 below Fahrenheit it becomes malleable and can be fractured in that state," Jasper said. "It takes about eight minutes to get the temperature stable."
From there, the munitions are sent down a conveyer to a hydraulic press that smashes them into small pieces of metal that can be salvaged or recycled.
"In this condition, it's no longer usable as military equipment and is no longer dangerous," Jasper said. "We have just eliminated the hazard it once posed."
The press, which applies 750 tons of pressure, also serves as an explosive compression chamber. The entire process is automated and controlled by computers from a nearby site.
"Since we are working with potentially explosive ordnance, we try to be as careful and methodical as possible," Jasper said.
Ordnance Recovery Technician John McPartland estimates that 47 trays of munitions are processed each day at the plant.
"With 10 to 12 grenades in each tray, that's about 2,000 a week," McPartland said.
Jasper said there is a possibility that the cryofracture process is a mission that may grow in the near future.