Disturbed Molten Metal Surface With High Turbulence

DOE-HDBK-3010-94

4.0 Solids; Metals

The increase in ARFs are attributed to the higher convective flows and increased turbulence.

The Mass Median Diameter shown in Figure A.17 is 4.2 m Geometric Diameter and would

approximate a 14 m AED particle. Thus, an RF of 0.5 is a conservative assumption.

Carter and Stewart (1970) surveyed the data available primarily in the United Kingdom on

the airborne release of plutonium during self-sustained oxidation. Based on the large body of

data available, they recommended the following values for ignition and burning in air

(melting), with air velocity less than 100 cm/s (static):

geometric mean

ARF 7E-6/RF 1.0

ARF 1E-4/RF 1.0.

Haschke (July 1992) reported in his conclusions "If the largest diameter of releasable

materials is assumed to be 10 m, the maximum releasable mass fraction for plutonium+O2

is 0.0007 ...". Tables II through V that list the distributions state "Particle diameters are

geometric, not aerodynamic." The fact that all estimates are geometric diameters, not AED,

was confirmed in conversations with the author. If the GSD is assumed to be 2.0, the mass

fraction of particles 10 m AED and less would be two or more orders of magnitude less.

Thus, the ARF and RF of 5E-4 and 0.5 from Mishima's data above that results in a mass

fraction of 10 m AED and less particles of 2.5E-4 certainly would bound Haschke's results.

Based on the results reported for this configuration, bounding ARF and RF values are

assessed to be 5E-4 and 0.5.

4.2.1.1.4 D istu rb ed M olten M etal S u rface W ith H igh T u rb u len ce. This

subsection examines conditions involving flowing metal or actions involving continual

exposed surface renewal of molten metal. Very energetic reactions of plutonium compounds,

such as bulk hydrides, are representative of this phenomenological range as well.

Stewart (1963) reported on the oxides formed by heating small pieces (less than 13 g) of

unalloyed and delta-alloy plutonium metal to various temperatures in various atmospheres.

Two shapes were used: billets (cylinders 7 mm diameter by 10 mm long) and swarf

(turnings). Various experimental configuration were needed for different experimental

conditions. The data for higher temperature oxidation (in the region of temperatures found

during self-sustained oxidation) and other pertinent information are covered in subsection

4.2.1.1.3. Results of one experiment in pure oxygen, which resulted in a violent reaction,

are shown below:

delta-phase plutonium, >1000 oC, 5.34 g, oxygen atmosphere, ARF 2.1E-2, violent

reaction, MMD 0.3 m (AED) ...

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