Dissolving Lin e

DOE-HDBK-3010-94

Appendix B; Plutonium Recovery Facility

transfer to the glovebox itself, and is equipped with a hopper that physically prevents

operators from reaching into the impaction area. The machine also is interlocked to shut off

if the gloveport covers for this area are not in place during operation.

The impactor provides output material less than 1 inch in particle size. This material is then

weighed and batched in the same manner as oxide. Only one set of impacted residue is

allowed unbatched at a time to prevent inadvertent mixing of already assayed material, and

the impactor unit is monitored continuously for holdup.

Once material has been placed in one of the spring-loaded batching cans, it can temporarily

be placed in a shielded metal storage rack. The storage compartment can hold up to six

batching cans at a time. When material is needed in the appropriate dissolving line, the

chainveyor access door is opened and the batch can is placed in one of the carriers on the

chainveyor system. The carrier is then sealed and the operator directs the material to either

the oxide or the residue dissolution line.

2.2.2.2 D issolvin g L in e

The dissolving line consists of three physically separate gloveboxes installed as a single

mounted unit. The three gloveboxes are for oxide, residue, and metal dissolution

respectively. Feed to the oxide and residue gloveboxes comes from the feed preparation

chainveyor. Feed to the metal dissolution glovebox is provided by a hood and airlock

arrangement identical to that on the feed preparation glovebox. Feed material for the metal

dissolution line comes directly from the H-12 Plutonium Vault Facility and consists of

recycle material ready for processing upon receipt.

2.2.2.2.1

O xid e D issolu tion

A simple representation of the oxide dissolution process is presented as Figure B.6.

Plutonium oxide is dissolved in a concentrated nitric acid solution with fluoride

catalyst (from potassium fluoride) at near boiling temperatures. Aluminum nitrate

nonahydrate is added once dissolution is complete to minimize corrosion and break up

any plutonium and fluoride complexes formed. The dissolver solution is transferred

via air eductor vacuum through a cartridge filter to the vacuum run tank. The liquid

is then transferred to the accountability tank through another cartridge filter by means

of a liquid-to-liquid mixing eductor. From the accountability tank, liquid is

transferred via a small gear pump to tank farm vessel #1 or #2.

The dissolver is a 30-liter slab vessel with a mechanical agitator. Numerous

connection lines to the dissolver include a purge/flush line, a sample line, chemical

Page B-27