Table 8.3 Interim Recommendations for Storage of Plutonium Metal and Plutonium Oxide at Department of Energy Facilities cont'd

DOE-STD-1128-98

Table 8.3 (cont'd)

For packages whose masses continue to increase since initial packaging or

for which historical mass data are unavailable (see item 6 above), a mass

increase greater than 15 g per kilogram of plutonium over a one-year period

indicates a hydride-catalyzed oxidation reaction.(a)

ii) For a package whose mass has remained constant over a period of several

years (less than 0.5 g change) from its reference value, then undergoes an

annual mass increase of more than 2 g per kilogram of plutonium, hydride-

catalyzed reaction is indicated. Such a package is particularly suspect. The

indications are that a previously sealed container may now be breached and

that the continuing reaction may lead to rapid containment failure within 12

to 24 months

c. The measured package mass, relative to the reference mass, corresponds to

the mass that indicates formation of oxide with a volume exceeding 10% of

the free volume of the inner vessel. Each 1-g increase in mass corresponds to

formation of 1.5 cm3 of oxide with a density of 50% of the theoretical value

of 11.46 g/cm3.

Inspected containers exhibiting abnormalities (e.g., external contamination,

bulging, discoloration, or other anomalies) should be repackaged in accordance

with well-defined procedures (see items 3 and 4 above). Handling such

containers outside of a glove box or conveyor confinement requires respiratory

protection until the package is placed in an overpack container (e.g., taped metal

can or sealed plastic bag) before further handling and transport.

As an interim measure, material that is repackaged may be placed in a food pack

can or slip-fit (Vollrath) container with a secured lid. If possible, metal should be

repackaged in a configuration containing at least one gas-tight seal. No plastic

material should be in direct contact with plutonium metal or oxide, and use of

plastic in outer layers of packaging should be minimized.

When packaging metal, hazardous or pyrophoric material such as plutonium

hydride should be removed. However, it is not necessary to remove protective

oxide film. Metal should be packaged in as dry and inert an environment as

possible to minimize corrosion (<100 ppm H20).

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