Reduction Line Example Assessment

DOE-HDBK-3010-94

7.0 Application Examples; Reduction Line Example

The ARF and RF values for venting of pressurized powders at confinement failure

pressures less than 0.17 MPag are 5E-3 and 0.4 (subsection 4.4.2.3.2). It would be

equally appropriate to use the ARF and RF values of 5E-3 and 0.3 (subsection

4.4.2.2.2) for powder shielded from a deflagration by a container. If the slightly

higher value is used, the initial respirable source term is:

(1000 to 2000 g) * 1.0 * 5E-3 * 0.4 = 2 to 4 g

The last issue to be examined is the potential for hydrogen accumulation in the

reduction furnace itself. This is closely related to the pressure seal failure case that

has already been examined because the only way for hydrogen to be present in the

furnace atmosphere is if the reduction can pressure seal has failed. In the example

process, an explosion would not be possible as the furnace is inerted with argon and

contained in a glovebox inerted with nitrogen. The use of air in the reduction furnace

atmosphere would never be appropriate due to product quality concerns alone. For

the sake of example, however, an air atmosphere is assumed present for some reason.

Maximum energy liberation occurs at stoichiometric mixing, which is a 33% by

volume hydrogen concentration. If the free volume in the furnace is 85 l (3 ft3), 28 l

of hydrogen would be available to react. The high temperature of the furnace volume

makes it conservative to assume that the given volume of hydrogen is ~ 1 mole,

which has an available energy in combustion of 68,000 cal. At a standard conversion

of 1100 cal/g of TNT, this corresponds to a TNT equivalent of 62 g if the reduction

furnace will contain the reaction to significant pressures. This would be expected to

blow out gloves in the vicinity and possibly fail windows in the immediate vicinity as

well. The source term will not exceed the maximum already estimated for the

pressure seal failure case (10 to 20 g) as it is the same phenomena. The molten

plutonium is not itself reacting explosively with anything. It is being acted upon by

an external force. In any case, a reasonable case can be made that this event is not

physically feasible for the system as it is operated (i.e., inerted).

7.3.8.3

Reduction Line Example Assessment

The 10 to 20 gram source term considered excessively conservative for this example could

exceed 25 rem at the site boundary for conservative meteorology and no deposition if the

release is completely unmitigated. With deposition alone accounted for, the unmitigated

release dose is less than 10 rem. The more reasonable spectrum of results examined might

exceed 5 rem unmitigated for the no deposition case. The significance of any one of these

numbers is limited. This operation does present more potential concerns than operations

such as dissolution, but worker safety is still the principle focus for this operation.

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