Interim Recommendations for Storage of Plutonium Metal and Plutonium
Oxide at Department of Energy Facilities
The following recommendations are made to improve current plutonium storage safety
practices. Until new equipment and facilities become available to package plutonium based
upon long-term standards, these recommendations are applicable to plutonium metal or
plutonium oxide stored outside of glovebox lines in containers that do not have certified
hermetic seals (i.e., per ANSI N14.5 (ANSI, 1997a)).
Plutonium solutions, metal turnings, or particles with specific surface areas
greater than 1 cm2/g should not be stored outside of glove boxes.
All packages containing plutonium metal should be taped, re-taped, and placed
in plastic bags prior to handling.
Inspections should incorporate use of adequate personnel protection. Inspection
practices should be codified in surveillance plans. These plans should reflect
current facility operating status. There must be personnel radiological
surveillance during all handling operations. Personnel protection during
operations should include protective clothing and gloves and, if necessary,
Inspection of containers should be integrated with audits for materials control
and accountability (MC&A) to minimize container-handling and attendant
radiation exposure to ALARA levels.
Containers should be inspected for abnormalities (e.g., mass change, container
deformation, or discoloration) using visual inspection, weighing, or video
surveillance where such capability exists. Findings should be recorded for safety
and MC&A evaluations. Visual inspections should be made at intervals of 1
week and 1 month after the material's initial containment and annually thereafter.
Packages containing more than 0.5 kg of plutonium metal should undergo an
annual surveillance in which the total mass of the package is determined to an
accuracy of ±0.5 g and compared with the preceding year's mass and with the
initial (reference) mass at the time of packaging. A storage package should be
evaluated (e.g., opened and inspected, radiographed) if any of the following
conditions are evident:
a. The outer storage vessel is bulged or distorted.
b. Hydride-catalyzed oxidation is suspected. Such reaction is indicated by a
in either of two circumstances: