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Sunday, June 05, 2005

Rocket fires determined to pose no risk

By DAVID SALE of the East Oregonian
dsale@eastoregonian.com



Army site project manager Don Barclay, with a full-size model of a GB rocket, points to the ignition site of the last three fires. Staff photo by David Sale
HERMISTON — The project manager of the Umatilla Chemical Agent Disposal Facility said studies have shown it’s safe to resume processing chemical weapons even though an Army task force has yet to pinpoint the exact cause of recent rocket fires.

Depot officials expect to get the go-ahead from the state Department of Environmental Quality in a matter of days to resume incineration operations, despite the chance of future fires.

“The right thing, from a public safety standpoint, is to resume the destruction of these rockets, and that’s the recommendation I’ve made,” said Don Barclay, Army site project manager. “Based on the results of our inquiry, I firmly believe it’s safe to continue.”

The three fires, which occurred April 7, April 23, and May 18, began while the M55 rockets were being cut into sections inside the plant’s Explosive Containment Room. No workers were threatened and there was no danger of chemical agent escaping. The room worked as designed, containing the low-level blast and ensuing fire, which was put out by the containment system.

But the rapid succession of fires — compared to the experience of other chemical incinerators operated by the Army — prompted a shutdown while the incidents were studied. The task force is composed of members of the U.S. Army Corps of Engineers, the U.S. Army Research Laboratory, the U.S. Army Armament Engineering and Technology Center, Sandia National Laboratory, and the plant’s operating contractor, Washington Group International.

“The potential for this problem was recognized from the beginning,” said Doug Hamrick, general manager of Washington Group International. “But the original estimate was one fire per 100,000 rockets processed. With three in six weeks, there was a question if the facility would withstand the extra stress.”

When operations were halted May 22, the Umatilla Chemical Depot had destroyed 14,531 rockets, or about 16 percent of the facility’s stockpile.

An inspection by the U.S. Army Corps of Engineers confirmed that the containment room, built of steel-reinforced concrete 28 inches thick, is more than adequate to contain additional fires. The three previous fires resulted in only minor damage to the disposal machinery.

Since the cutting process is fully automated, and the rockets are drained of their nerve agent before being sectioned, a fire in the containment room does not present a threat to Depot workers or the general public, officials said.

Regardless, the task force recommended increased fire prevention measures inside the containment room, and those installations are being made.

One key component is a new type of spray nozzle to clean and cool the guillotine-like shear blade, which cuts the rockets. Video records show that the old nozzle tended to brush the rocket body, diverting its spray away from the blade. Officials believe this was likely a contributing factor in the fires.

Depot workers are also adding two additional sprayers behind the shear blade, where the rocket body advances through the machine. All three of these sprayers run continuously during the cutting process.

“We’ve also added gauges to monitor the temperature and pressure inside the room, and moved the fire detection systems to a new, safer spot,” Hamrick said.

Each of the previous fires began at either the fifth or seventh cut, when the blade makes contact with the rocket propellant.

The depot at Pine Bluff, Ark., has experienced two fires during this step of the disposal process, as have other Army disposal sites.

Determining the exact cause of the fires is likely to prove more difficult than controlling them. Suspicion has centered on the rocket propellant, due to the fact that all three fires in Umatilla occurred in the same batch of rockets, manufactured in October 1962.

In response, the Depot will collect nine propellant samples from the batch, by unscrewing the warheads from the rocket’s motor sections.

 The warheads will be returned to their “igloos” or storage bunkers, while the Army ships the motor sections to Picatinny Arsenal in New Jersey, where scientists will compare the propellant to dated samples provided by the manufacturer to determine whether some change has happened to the Umatilla rockets.

“There’s certain things that can make the propellant more sensitive to heat, shock or static electricity,” Barclay said. “It’s one solid piece inside the rocket, so one thing they’ll look for is cracks in the material.”

The scientists will also examine the chemical composition of the propellant, to see if age or climate has rendered it less stable.

Depot workers will begin collecting the samples Monday, and the test results are expected in six to eight weeks. But even if the propellant in this batch of rockets is found to be degraded, a solution to the fires will be hard to come by.

“For instance, we could change the shear location or the blade speed, but that could give rise to unintended consequences,” Hamrick said. “Slowing the shear blade would prevent shock, but the resulting higher temperature could wind up increasing the risk of a fire.”

Although Barclay said he considered the frequent fires to be “unacceptable,” he reluctantly added: “We may just have to accept the increased frequency of fire while we process the October 1962 lot. They seem to be the problem — the other lots haven’t shown this tendency.”