Plutonium Alloys - doe-std-1128-98

DOE-STD-1128-98

2.3.2 Plutonium Alloys

Alloying plutonium gives rise to a host of materials with a wide range of physical,

chemical, and nuclear properties.1 The search for and development of new alloys has

been focused mainly on the manufacture of atomic weapons, reactor fuels, heat

sources, and neutron sources. The challenge of alloy development is how to

maximize the desired properties without adding undesired ones. Unfortunately, some

properties mutually exclude others (e.g., a gain in hardness usually results in a loss of

ductility), so users may be forced to rethink their needs.

The radiological hazards of a plutonium alloy taken through its product life cycle

differ from those of the pure metal isotope by virtue of the alloy's properties, which

affect its form (i.e., its chemical composition, density, and geometric shape). Because

form can be radically changed by external conditions (e.g., heat, pressure, and

chemical atmosphere), a knowledge of the following properties will aid in evaluating

the radioactive hazard:

-- melting point

-- diffusivity

-- viscosity

-- strength

-- vapor pressure

-- ductility

-- corrosion resistance

-- pyrophoricity.

In nuclear fuel applications, the neutron absorption cross-section of the alloying

elements and impurities must also be considered for its effect on radiation exposure.

2.3.3 Plutonium Compounds

Much of what was said in Section 2.3.2 about the properties of plutonium alloys also

applies to plutonium compounds because both are mixtures of plutonium and other

elements.

Plutonium is the fifth element in the actinide series, which consists of elements with

properties that stem from partial vacancies in the 5th electron shell. These elements

form the seventh row in the periodic table. In general, there are four oxidation states:

III, IV, V, and VI. In aqueous solutions, plutonium (III) is oxidized into plutonium

(IV), which is the most stable state. The compounds PuF4, Pu(I03)4, Pu(OH)4, and

Pu(C2O4) 2 6H2O

See Volume 1 (Section 2) and Volume 2 (Section 5) of the Plutonium Handbook: A Guide to the Technology (Wick, 1967);

Plutonium (Taube, 1964); and Chapter 11 of the"Reactor Handbook" in Materials, vol. 1 (Tipton, 1960). Beginning in 1957, a series

of international conferences were held whose proceedings contain a wealth of information on plutonium alloys. From 1960 through

1975, the conferences were held every five years and produced a proceedings for each conference: Refer to The Metal Plutonium

(Coffinberry and Miner, 1961); Plutonium 1960 (Grison et al., 1961); " Plutonium 1965" (Kay and Waldron, 1966); "Plutonium 1970

and Other Actinides," Parts I and II (Miner, 1971); and "Plutonium 1975 and Other Actinides" (Blank and Lindner, 1976).

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