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5 How Radiological Weapons Work
5.1 Overview
At the most basic level, radiological weapons are fairly straight-forward—highactivity radioactive sources can be set out in such a way as to expose people to high
levels of radiation, or they can be disseminated to spread radioactive contamination.
Radiation exposure devices (REDs) would most likely be used to attempt to harm or
kill people using radiation; radiological dispersal devices might be intended to try to
cause harm, but are more likely to serve to spread non-lethal contamination to deny
access to the contaminated areas and to cause economic and societal disruption due
to the public’s fears of radiation and radioactivity.
5.2 Types of Radiological Weapons
As noted above, the two primary categories of radiological weapons are those
intended to irradiate people and those intended to spread contamination—radiological exposure devices (REDs) and radiological dispersal devices (RDDs) respectively.
Consider, for example, a terrorist group that has stolen a high-activity (40 TBq) Co-60
radioactive source for malicious purposes. What impact can such a source have?
5.2.1 Radiological Exposure Device
The greatest health effects will come from keeping this source intact and concentrating the radioactivity to achieve the highest radiation dose rate. With a gamma
constant of 3.945 × 10
2 mSv/hr per TBq at a distance of 1 m [12], this source would
produce a radiation exposure of 15,780 mSv/hr, or slightly less than 16 Sv/hr at a
distance of 1 m from the source. This will expose a person one meter from the source
to a fatal dose of radiation in less than one hour, and any people within 2 m of the
source will receive a fatal dose of radiation in 2 h or less (assuming they receive
competent medical care).
What danger is posed by a 10 TBq source of Co-60 placed in a movie
theater?
The gamma constant for Co-60 is 3.945 × 10
2 mSv/hr per TBq at a distance
of 1 m, so the dose rate from this source would be about 3.9 Sv/hr at this
distance—we will round this up to 4 Sv/hr to make the calculations simpler. If
we assume that nobody leaves the theater, Table 5.1 show what the radiation
doses to movie-goers will be at the end of a 2-h movie:
5 How Radiological Weapons Work
5.1 Overview
At the most basic level, radiological weapons are fairly straight-forward—highactivity radioactive sources can be set out in such a way as to expose people to high
levels of radiation, or they can be disseminated to spread radioactive contamination.
Radiation exposure devices (REDs) would most likely be used to attempt to harm or
kill people using radiation; radiological dispersal devices might be intended to try to
cause harm, but are more likely to serve to spread non-lethal contamination to deny
access to the contaminated areas and to cause economic and societal disruption due
to the public’s fears of radiation and radioactivity.
5.2 Types of Radiological Weapons
As noted above, the two primary categories of radiological weapons are those
intended to irradiate people and those intended to spread contamination—radiological exposure devices (REDs) and radiological dispersal devices (RDDs) respectively.
Consider, for example, a terrorist group that has stolen a high-activity (40 TBq) Co-60
radioactive source for malicious purposes. What impact can such a source have?
5.2.1 Radiological Exposure Device
The greatest health effects will come from keeping this source intact and concentrating the radioactivity to achieve the highest radiation dose rate. With a gamma
constant of 3.945 × 10
2 mSv/hr per TBq at a distance of 1 m [12], this source would
produce a radiation exposure of 15,780 mSv/hr, or slightly less than 16 Sv/hr at a
distance of 1 m from the source. This will expose a person one meter from the source
to a fatal dose of radiation in less than one hour, and any people within 2 m of the
source will receive a fatal dose of radiation in 2 h or less (assuming they receive
competent medical care).
What danger is posed by a 10 TBq source of Co-60 placed in a movie
theater?
The gamma constant for Co-60 is 3.945 × 10
2 mSv/hr per TBq at a distance
of 1 m, so the dose rate from this source would be about 3.9 Sv/hr at this
distance—we will round this up to 4 Sv/hr to make the calculations simpler. If
we assume that nobody leaves the theater, Table 5.1 show what the radiation
doses to movie-goers will be at the end of a 2-h movie: