Nuclides/isotopes and uses of plutonium - DOE-HDBK-1145-2001

Radiological Safety Training for Plutonium Facilities

DOEHDBK11452001

Instructor's Guide

Explain that the half-life is the

D. Natural plutonium

amount of time it takes for

one-half of the material to

The half-life of plutonium is so short compared to

decay.

the age of the earth that if plutonium had existed when

the earth was formed, plutonium would not exist today.

So, for all practical purposes, plutonium must be man-

made.

The earth is thought to be

Remnants of a natural reactor have been

approximately 4.5 billion years

discovered in Africa, and it is believed to have

old.

operated for millions of years. Very small traces of

plutonium have been found in uranium ore, resulting

from cosmic-ray produced neutron bombardment of

uranium.

Show OT 8.

II. Nuclides/isotopes and uses of plutonium

Obj. 2

A. Predominant plutonium isotopes

Identify the characteristics,

grades, and predominant

Atoms of a specific element can exist in several

isotopes of plutonium.

forms. The difference between the forms is the

number of neutrons in the nucleus. These forms are

Explain that an isotope is an

called isotopes of an element. Most elements in

element with the same number

nature have several different isotopes. (They have the

of protons, but a different

same number of protons, but a different number of

number of neutrons.

neutrons). Plutonium has 15 isotopes.

Nuclide is a broader term than isotope and refers to

any combination of protons and neutrons that exists in

more than a transient state. An isotope is a specific

combination of protons and neutrons, which defines it

as a subset of an element; the two need to be

referenced together, such as "an isotope of plutonium."

The shorter-term nuclide will

The predominant nuclides are Pu-238, Pu-239,

be used for this instruction.

Pu-240, Pu-241, and Pu-242. Each has a specific

application.