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).