Rocky Flats Plant Fire, 1969 cont'd

Spontaneous Heating and Pyrophoricity

DOE-HDBK-1081-94

ACCIDENT CASE STUDIES

been oily and coated with residual CCl4 (carbon tetrachloride). Once ignited, the fire spread

through several hundred interconnected gloveboxes in the two connected buildings.

The fire started in the west end of the north line, progressed eastward, crossed over to the

south line through the interconnecting boxes, and spread through the south line. The fire

spread through the machining boxes at the east end of 776 and into the inspection boxes

in 777. Damage was extensive. Both Benelex, a combustible neutron shielding material added

to the gloveboxes, and the combustible Plexiglas glove box windows contributed to rapid

spread of the fire.

The main fire lasted about 4 hours, with minor flareups occurring through the next night.

After futile attempts to control the fire with conventional procedures, the firemen finally

resorted to the unorthodox procedure of applying water to bring the fire under control. This

was the first time in history that water had been used to fight a plutonium fire. Despite

attendant criticality dangers, the use of water was successful in controlling the fire.

The interiors of the two extremely large, high-bay buildings were grossly contaminated. An

extensive, long-term cleanup effort was necessary for decontamination. Limited production

was restarted about 6 months later in a temporary production line constructed in an adjacent

building.

As damaging as the fire was, the water use prevented breaching of the outer walls and

ceiling of 776 and 777, thus preventing a major release of plutonium to the environment.

The small amount of plutonium released--almost entirely contained on plantsite--was about

0.0002 curies. Slightly contaminated external areas were subsequently cleaned up.

Fortunately, the fire caused no direct deaths. However, one fireman received significant

plutonium lung burdens, and other firemen and personnel incurred smaller radiation

inhalations and exposures while fighting the fire and later cleaning up heavily contaminated

areas.

Immediately prior to the fire, personnel levels were significantly cut with no real decrease in

work load or production demands. Strict attention to plutonium chip handling no longer

seemed to have been a top priority.

The many lessons learned from this 1969 fire include the following:

Plutonium pyrophoricity is unpredictable as to when it may occur.

Combustible materials such as Benelex and Plexiglas must be kept to a minimum in

process buildings.

Uncleaned and uncanned briquettes cannot be left unprotected and unattended on

off-shifts.

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Pyrophoricity