Calcination and Hydrofluorination Example Assessment

DOE-HDBK-3010-94

7.0 Application Examples; Dry Processing Line Example

and the storage racks have a significant amount of open space, the jugs will soften

and fail and the powder contents will spill to the glovebox floor with limited, if any,

interaction with plastic during combustion.

In this example, however, significant interaction with burning plastic is expected.

The quantities of material in relation to container size is not large, and the containers

sit upright in recessed wells in a solid storage rack. The powder will, therefore, sit

in the well while the entire plastic jug burns. If the fire is presumed to happen with

maximum material loading, the initial respirable source term is:

Calciner Feed: 23,000 g * 1.0 * 1E-2 * 1.0 = 230 g

Hydrofluorinator Product: 3600 g * 1.0 * 1E-2 * 1.0 = 36 g

The potential contribution of material inside the calciner or hydrofluorinator can be

neglected as the only available release mechanism would be heating of powder in a

vessel that is already at temperatures in excess of at least 370 oC. Likewise, the

plutonium-contaminated liquid in the slab tank can be neglected. If it boils

(ARF = 2E-3, RF = 1.0), the most likely result, the release to the vessel vent

system is:

1000 g * 1.0 * 2E-3 * 1.0 = 2 g

Even if the release were treated as release of a superheated solution, the vessel blow-

out plug failure pressure would be at less than the 0.76 MPa (110 psia) associated

with 50 oC superheat. As previously noted in the ion exchange example in section

7.3.6, the ARF x RF for this phenomena is 6E-3, only a factor of three increase over

that already postulated. Even these relatively small releases could not typically be

concurrent with the calciner release postulated above as the cumulative quantity of

1 kg of plutonium is obtained only at the end of the calcining operating cycle, when

the calciner feed storage rack has not been refilled.

7.3.7.3

Calcination and Hydrofluorination Example Assessment

For a large fire in the gloveboxes or glovebox rooms, a bounding initial plutonium source

term is 230 g in the calciner and 36 g in the hydrofluorinator, or 266 g combined. This

large fire, like the large fire in the maintenance room of the wet processing line

(section 7.3.5), is very unrepresentative of the majority of accidental releases that could be

postulated for the example facility. Clearly the calcination and hydrofluorination operating

areas represent locations where special attention to minimizing the likelihood of even small

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