70
7 Physical Effects of Radiological Weapons
had measurable levels of contamination onboard and passengers brought contamination to over 50 international destinations as well [14, 15]. It should be noted that
this wide spread of contamination was the result of the incidental spread of a small
amount of radioactivity that spread from two men who poisoned a third; a deliberate
covert attack against a major city waged with malicious intent would almost certainly
be far more widespread.
The effect on transportation infrastructure can be especially disruptive, especially
in cities that rely heavily on mass transportation, such as London and New York City.
In many cities, the train stations are connected to the outside atmosphere by grates
and the design of the train stations and the piston action of trains traveling along the
tracks pumps air through the system, providing fresh air for passengers and workers.
If this air is contaminated, this same piston effect will be quite effective at pushing
radioactivity throughout the subway system and spreading it to distant parts of the
city. This can not only spread contamination in directions that might seem counterintuitive, but can also cause the subway system to be shut down, severely impacting
the ability of citizens to travel from home to work and back, to visit friends, to attend
events in other parts of the city, and so forth.
7.7 Radioactive Debris
After the emergency phase is over the city will be faced with cleaning up the radioactive contamination. The details of this remediation will be discussed in Chaps. 20
and 21; here we will discuss factors related to the scale of the response that will be
required. The primary factors that will impact future remediation efforts include:
• The form and physical volume of radioactive materials used in the device,
• The degree of dispersibility,
• The strength of the explosion (for an explosive RDD),
• The area in which the device is used, and
• The extent of the contamination.
Radioactive sources come in a variety of physical and chemical forms. A fine
powder or liquid will disperse far more readily and more evenly than will a radioactive
metal alloy; powder that is sealed within a welded capsule will not disperse as readily
as will the same powder that is in an unsealed form. Soluble materials are easily
spread by rain or by water used to fight fires, contaminating the sewer system, waste
water treatment plants, parks, rivers, and will lead to a longer and more expensive
remediation in the future.
All else being equal, a greater volume of radioactive material will contaminate a
larger area than will the same source activity that is physically smaller. For example,
one gram of pure
60 Co will have a volume of about 17 µl. If the average particle
diameter is 5 microns then each particle will have a volume of about 5 × 10
−11
µl. Thus, a source that is pure
60 Co will contain about 350 million particles. By
7 Physical Effects of Radiological Weapons
had measurable levels of contamination onboard and passengers brought contamination to over 50 international destinations as well [14, 15]. It should be noted that
this wide spread of contamination was the result of the incidental spread of a small
amount of radioactivity that spread from two men who poisoned a third; a deliberate
covert attack against a major city waged with malicious intent would almost certainly
be far more widespread.
The effect on transportation infrastructure can be especially disruptive, especially
in cities that rely heavily on mass transportation, such as London and New York City.
In many cities, the train stations are connected to the outside atmosphere by grates
and the design of the train stations and the piston action of trains traveling along the
tracks pumps air through the system, providing fresh air for passengers and workers.
If this air is contaminated, this same piston effect will be quite effective at pushing
radioactivity throughout the subway system and spreading it to distant parts of the
city. This can not only spread contamination in directions that might seem counterintuitive, but can also cause the subway system to be shut down, severely impacting
the ability of citizens to travel from home to work and back, to visit friends, to attend
events in other parts of the city, and so forth.
7.7 Radioactive Debris
After the emergency phase is over the city will be faced with cleaning up the radioactive contamination. The details of this remediation will be discussed in Chaps. 20
and 21; here we will discuss factors related to the scale of the response that will be
required. The primary factors that will impact future remediation efforts include:
• The form and physical volume of radioactive materials used in the device,
• The degree of dispersibility,
• The strength of the explosion (for an explosive RDD),
• The area in which the device is used, and
• The extent of the contamination.
Radioactive sources come in a variety of physical and chemical forms. A fine
powder or liquid will disperse far more readily and more evenly than will a radioactive
metal alloy; powder that is sealed within a welded capsule will not disperse as readily
as will the same powder that is in an unsealed form. Soluble materials are easily
spread by rain or by water used to fight fires, contaminating the sewer system, waste
water treatment plants, parks, rivers, and will lead to a longer and more expensive
remediation in the future.
All else being equal, a greater volume of radioactive material will contaminate a
larger area than will the same source activity that is physically smaller. For example,
one gram of pure
60 Co will have a volume of about 17 µl. If the average particle
diameter is 5 microns then each particle will have a volume of about 5 × 10
−11
µl. Thus, a source that is pure
60 Co will contain about 350 million particles. By