The standard accepts two approaches to verification that materials

DOE-STD-3013-2000

temperatures above 750C, while the oxides fired at lower temperature are made up

of medium size grains. This work thus indicates that for oxalate derived plutonium

oxide, the number density of respirable particles may actually increase for

calcination temperatures above 750C.

2. The standard accepts two approaches to verification that materials have been

adequately stabilized: 1) testing essentially every container loading (each container

would have a moisture measurement applicable to it, even if the measurement was

of a batch sufficient to fill several containers) or 2) use of a "qualified process" for

stabilization and packaging that would reduce the requirements for materials testing.

1) Stabilization at 950C and appropriate handling prior to packaging ensure that

the only significant mechanism for container pressurization is decomposition of

readsorbed water into hydrogen gas. Thus, verification of adequate stabilization

requires only measurement to ensure that residual moisture in the packaged

material is below the threshold specified in Criterion 6.1.2.3.

The LOI test is accomplished by heating the sample to at least 1000C for at

least one hour and determining the resulting weight loss. The LOI test has great

attractiveness for application to stabilized plutonium materials because it is

simple, inexpensive and highly practical in a glovebox environment. LOI has the

unfortunate characteristic of not directly measuring the parameter of greatest

interest hydrogenous material content. Decades of experience with pure

plutonium oxide and recent results in the MIS program with oxides obtained

from Hanford and Rocky Flats and tested at LANL indicate that LOI is an

adequate test for moisture for fairly pure oxides (plutonium content greater than

approximately 80-85 wt%) [Mason et al. 1999]. However, the MIS program also

shows that lower assay materials of interest to the 94-1 program almost always

fail the standard LOI test because of impurities other than water that become

volatile at LOI test temperatures. Salt impurities are particularly troublesome in

providing false negative indications. This Standard therefore encourages use of

LOI for fairly pure plutonium oxide materials and use of moisture-specific

alternative methods for lower grade materials.