Residue Dissolution - h3010v10275

DOE-HDBK-3010-94

7.0 Application Examples; Dissolving Operations Examples

The main value of the release estimates is again the indication that the unmitigated

consequences from the oxide dissolution are low and, accordingly, worker safety is the

principle focus of concern. This is an important perspective that, again, may be useful in

applying a graded approach to facility management.

7.3.3 Residue Dissolution

Release topics explored in this example are listed in Table 7-6.

Table 7-6. Residue Dissolution Example Topics

Liquid

Metal

Powder

Surface

Criticality

Contamination

- Venting of

- N/A

- None

pressurized liquids

7.3.3.1

Hazard Summary

This activity receives, via a conveyor, residues heavily contaminated with plutonium that

have been reduced in size in the feed preparation operation. This material is placed in a feed

hopper that slowly feeds it into the nitric acid dissolver, after which only liquid materials are

handled. This operation is virtually identical to the oxide dissolution operation previously

described. The only new complication in residue dissolution is the need for a screw feed

conveyor to prevent an excessive dissolution rate of residue impurities from causing an

eructation in the dissolver vessel.

7.3.3.2

Release Estimation

The only new potential energetic phenomenon is an eructation from the dissolver vessel due

to an excessive impurity feed rate.

A. Dissolver Eructation. The dissolution process is a batch operation. The

maximum feed allowed in any one batch is 1000 g as plutonium. The maximum

release is obtained if the eructation occurs when the majority of the plutonium has

been fed to the dissolver. The eructation is a relatively low pressure phenomena, and

any gas backleakage through the material-filled conveyor would have almost no effect

on the feed residue. For an initial bound, a DR of 1.0 is conservatively assumed.

Small eructations are handled by the vessel vent system. A larger eructation can

drive gas into the glovebox. In a worst case, the dissolver blowout plug may fail,

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