Hazards Created by Oxidation and Pyrophoricity

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

these substances is also provided. Table 2.9 is not meant to replace the Material Safety

Data Sheet (MSDS) available from chemical manufacturers; rather, it is intended to help

readers recognize the toxicity of these chemicals and identify any possible side effects

from their use that could jeopardize radiation safety or plutonium containment.

2.6.3

Hazards Created by Oxidation and Pyrophoricity

This section describes the oxidation and burning characteristics of plutonium,

summarizes the storage properties of the metal and oxides, and presents recommendations

for their storage conditions. Waste remediation plans for TRU materials and the

necessity for dealing with ton quantities of plutonium metal from the retirement of

weapons require the identifying of long-term and intermediate-term waste forms with

appropriate stability. Economic considerations make clear the importance of generating

few, if any, new wastes in accomplishing this task.

2.6.3.1 Oxidation of Plutonium

The problems of oxidation of metallic plutonium were recognized shortly after

the discovery of plutonium, and extensive studies of the low-temperature

corrosion of plutonium and its alloys have been performed. Oxidation can

produce fine loose plutonium oxide, which disperses easily in glovebox systems,

complicating housekeeping chores. If not controlled, loss of accountability and

increased radiation exposure to personnel is certain. The reactivity of plutonium

metal is discussed in Section 2.3.1. The tendency for enhanced oxidation is

promoted by the self-heating properties of plutonium isotopes (discussed in

Section 2.5.1). A kilogram of 239Pu can easily reach an equilibrium temperature

of 80C in a glove-box environment (Raynor and Sackman, 1967). Thermally

isolated 238Pu metal can easily melt from its own decay heat. The heat generated

by oxidation may be sufficient to ignite nearby combustible materials. Metal

turnings and scrap should be reprocessed or converted to stable alternatives as

soon as practicable. Plutonium metal, its alloys, and its reactive compounds need

to be excluded from both oxygen and water vapor, but especially the latter since

it catalyzes and accelerates oxidation.

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