Plutonium Metal

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

Atom Ratio of 241Am to 241Pu (t=0) Produced by the Beta Decay of 241Pu as a Function

Figure 2.2.

of Time Since Chemical Separation

2.3

PHYSICAL AND CHEMICAL PROPERTIES

This discussion of plutonium's physical and chemical properties begins with plutonium metal,

followed by its alloys and compounds. Knowledge of the physical properties of these classes of

materials and how the plutonium was produced is the key to understanding and predicting the

hazards of working with this challenging element. According to Healy (1993), "Nature does not

decide what what happens to any material based on its radioactivity but rather on its form and

mass." Form and mass are determined by the engineering application and the kinds of processes

needed to achieve both intermediate and final products. Thus, to prevent nature from taking its

course, there can be no shortcuts in good practices for plutonium facilities.

2.3.1

Plutonium Metal

The metallic state of plutonium is undoubtedly the most complicated of all the elements.

Plutonium is a silvery-white metal, much like nickel in appearance. It has a low melting

point (640C) and an unusually high boiling point (3327C). The metal exists in six

allotropic forms, as indicated in Table 2.5. Two of the allotropic forms, * and *N,

contract upon heating; the other forms expand upon heating. At room temperature, pure

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