Radiological Safety Training for Uranium Facilities
Module 101 - Properties of Uranium
Both alpha and beta particles are emitted as part of decay series. For example, 238U decays by alpha
emission to 234Th; 234Th decays by beta emission to 234mPa; and so on, until stable 206Pb is finally
1. Decay Series
Uranium has two naturally occurring decay series: the "actinium" series, which has 235U as its
parent; and the "uranium" series, which has 238U as its parent. Many of our everyday encounters
with rad ioacti vity come fr om these d ecay seri es; examp les are r adon gas a nd radiu m.
U and 233U. The decay products from these
There a re also ma n-made iso topes of uranium -
radionuclides must be considered in the implementation of a radiological control program at a
facility where these uranium nuclides are present.
Uranium is a fissionable material, which means it can undergo nuclear fission. Nuclear fission is
a process in which a very heavy, unstable atom splits in two, or "fissions". When an atom
fissions, one large atom primarily becomes two smaller atoms, between one and seven neutrons
are given off (which may cause fission in nearby atoms), and a great deal of energy is given off
as radiation and in other forms, such as kinetic energy of the fission fragments. The radiation
Areas. Nuclear criticality associated with uranium will be discussed in greater detail later in the
D. Chemical Properties
Uranium is chemically reactive. It burns in air like magnesium; it is toxic like lead; and it forms a
large variety of chemical compoun ds. All the iso topes of uran ium have the same che mical reacti vity,
and all can be made into the many different physical and chemical forms discussed in this section.