Miscellaneous Incidents (Smith, 1956)

ACCIDENT CASE STUDIES

DOE-HDBK-1081-94

Spontaneous Heating and Pyrophoricity

injured by the blaze, two subsequently died. Reason for initiation of the reduction reaction in

the blender is uncertain and unprecedented. It was subsequently found that the calcium used

was particularly reactive.

Miscellaneous Incidents (Smith, 1956)

On June 16, 1954, employees of a high-energy-fuel laboratory were sampling 15 drums of

"bag fines" Mg powder, which were opened in a special room that had been purged with

nitrogen until the oxygen content had dropped below 1 percent. During sampling of the fifth

drum, the powder ignited suddenly. The flame shot out from the drum, immediately

subsided, and the operators left the room after replacing the drum cover. From an external

observation window, the employees noticed a gradual darkening of the drum's exterior,

moving down to within 2 to 4 inches of the drum bottom. The following day the drum was

opened and contained a definite yellow coloration, which was presumed due to formation of

magnesium nitride.

A massive block of metallic barium was cut into 3/4-inch square pieces while submerged in

kerosene. During attempts to remove residual kerosene with carbon tetrachloride (an

operation that had been performed many times before without incident), a violent reaction

dispersed glass fragments and burning barium over the immediate area. Similar explosions

have also occurred when Na, U, and Zr were treated with carbon tetrachloride.

Trouble had been experienced in getting a Kroll process reduction of ZrCl, with Mg to go to

completion. When the furnace was opened up, a slate grey material was noted on the surface,

which was thought to consist of Zr, Mg, and MgCl. A sample of this material, roughly 1/4

inch thick and 8 inches square, was removed for test and was totally inert when scratched

with a file or hit with a hammer. A piece of the sample melted under an oxyacetylene flame

but showed no pyrophoric properties. Samples were then placed in water and a slight

evolution of gas was noted. The following day an attempt was made to further wash the

samples in several changes of water. While under 5 inches of water and without any prior

evidence of reaction, an explosion occurred that shattered the laboratory bench, threw the

technician against the wall, and blew out a window 25 feet away. Portions of the water-

washed sample blown to the floor ignited and "spit" when stepped upon. Small samples were

subsequently tested and found to contain Mg, Zr, and 1 percent C.

Rocky Flats Plant Fire, 1969

On May 11, 1969, Rocky Flats Plant experienced the worst accident in plant history, a major

fire in the 776-777 building, initially caused by pyrophoric plutonium scrap. One of the

costliest industrial fires of all time--damages were estimated at between $26 to $50 million

dollars--this accident was intensified and confounded by a number of operational errors.

The fire at 2:27 p.m. Sunday was reportedly caused by spontaneous ignition of a 1.5-kg

briquette of plutonium alloy scrap contained in a metal can. This scrap was believed to have

Pyrophoricity

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