Uncontained Plastics/Elastomers

DOE-HDBK-3010-94

5.0 Surface Contamination; Contaminated, Combustible Solids

convective flow. Candidates for such a release include light, individually packaged material in

a non-robust container in an airplane crash fuel explosion, or possibly some small fraction

of material ejected from a violent waste drum overpressurization in a waste drum fire. A

critical point is that it is an airborne phenomena. Once waste lands on the ground and begins

to burn in place, this phenomena is not considered applicable for any foreseeable fire

conditions at DOE nonreactor nuclear facilities.

For the case of an overpressurized drum, the fraction of total material that fits this

requirement is small. The material must be ejected from the container in a direction attuned

with the flame, be heavy enough to cross the convective flow lines but light enough to

suspend momentarily in the flames, and be of such configuration that the material will ignite

and substantially combust in the time frame that it is in the flames. Even upon loss of lids

due to overpressurization, sealed waste drums would not eject the material violently enough

or in the correct direction to eject a large percentage of the contents in a direction attuned

with the flames. Typical individual pieces of contaminated combustibles are of sufficient

mass to pass through the flames with only localized ignition, let alone complete combustion.

Accordingly, this release fraction is not treated as a reasonable expectation for the majority

of waste in even large jet fuel fires. For more typical stresses, such as a large combustible

fire or a drum with combustible material venting around or through its lid, any use of this

ARF and RF is inappropriate.

For this data covering the types of phenomena discussed, an ARF of 4E-1 with a RF of 1.0

is assessed to be bounding for lightly scattered powder contamination. A bounding ARF of

8E-2 with an RF of 1.0 is applicable to air-dried solution or more adherent powders, such as

those which were damp at the time of entrainment or which have been smeared onto the

combustible surface. In both cases, the RF is a conservative value in the absence of

measured data.

5.2.1.4

U n con tain ed P lastics/E lastom ers

Experimental ARFs are available for three materials - polychloroprene (PC), polystyrene

(PS) and polymethylmethacrylate (PMMA). The results for the individual materials is

presented below but, due to the material and ARF range similarity, the ARF and RF for

polychloroprene and polymethylmethacrylate are combined.

The bounding ARFs and RFs for this class of materials under thermal stress are divided into

two groups - polychloroprene and polymethylmethacrylate, and polystyrene - by the

measured values. Based upon the experimental data, bounding ARF and RF values for the

PC + PMMA group are assessed to be 5E-2 and 1.0. The bounding ARF and RF value for

polystyrene is assessed to be 1E-2 and 1.0.

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