Air Line Rupture

DOE-HDBK-3010-94

7.0 Application Examples; Feed Preparation Example

holdup issues would arise. Accordingly, the phenomena can be considered bounded

by impact of contaminated non-combustible solids. The ARF and RF assigned are

1E-3 and 1.0 (subsection 5.3.3.2.2). The maximum initial respirable source term is:

1050 g * 1.0 * 1E-3 * 1.0 = 1.0 g

D. Air Line Rupture. Given that the air line is equipped with a flow-restricting

orifice and the ventilation system is normally operating, the event is expected to be

insignificant. For the purposes of example, it will be assumed that when the line

breaks, more flow is attained and/or ventilation flow is secured for whatever reason.

Even in these circumstances, the only obvious effect would be limited contamination

release from glovebox-mounted HEPA filters due to reverse flow. The break would

have to occur in close proximity to powder to significantly affect any in-line material.

The most powder that can be exposed at any one location is 2000 g, the maximum

quantity procedurally allowed at any one station. This material can be exposed

powder in the loading pan at the furnace or at the weighing and batching station,

although less material is typically handled. A maximum of 1000 g of plutonium as

contamination on residue can be exposed at the impactor station as well. This

material is not as susceptible to release as loose powder. For example, plutonium on

magnesium oxide crucible residues may be literally embedded in crucible pores.

Treating it like a loose, powdery surface contamination is extremely conservative.

If the air line does not break in close proximity to exposed material, all the material

in the glovebox is affected by the overall glovebox phenomena, and the DR for this

phenomena is 1.0. If the break is in close proximity to one batch (assume the batch

in the furnace pan), the DR is 0.4 for this material (2000/5000) and 0.6 for the

different phenomenological effect on the remaining material.

For the expected case where no material is in close proximity to the break and air

flow from the pipe, the phenomena is certainly bounded by aerodynamic resuspension

of powder exposed to normal ventilation flow. The ARF and RF assigned are

4E-5/hr and 1.0 (subsection 4.4.4.1). The maximum initial respirable source term is:

5000 g * 1.0 * 4E-5/hr * 1.0 = 0.2 g/hr

If the break occurred in close proximity to the furnace storage station (within ~ 30 to

40 cm), the 0.21 MPag flow could cause an effect more vigorous than simple

resuspension. The effect of any typical air line pressure (e.g., up to 0.7 MPag) would

be to produce some small level of pressurization in the glovebox and accelerated

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