16.2 Radiation Safety Considerations Relevant to a Radiological …
185
16.2 Radiation Safety Considerations Relevant
to a Radiological “Dirty Bomb” Interdiction
and Response
While there are a number of radiation safety practices that are common to a large
number, if not all, radiological circumstances, a radiological attack raises additional
issues. This is due, in part, to the fact that an accident involving the incidental
release of radioactivity is different than the malicious release of radioactivity with
the intent to cause harm. Consider: in 1987 an accident involving a 50.9 TBq Cs137 source resulted in four deaths, 120 individuals who required medical care, and
250 who required decontamination, and the cleanup created several thousand cubic
meters of radioactive waste [2]. Forty-four TBq, approximately 86% of the original
activity, of Cs-137 was recovered and accounted for. By comparison, a terrorist attack
would likely involve the malicious release of nearly 100% of the radioactive material.
Compared to a radiological accident, a terrorist attack is likely to involve:
• The release of a greater percentage of radioactivity from the source(s) used
• A larger contaminated area with contamination spreading further downwind
• Large amounts of airborne radioactivity during the initial release
• A wide variety of particle sizes due to heat and pressure from the blast
• Larger numbers of people with internal contamination due to absorption into
wounds, embedded fragments, and inhalation of airborne radioactivity
• Possible high-activity sources or source fragments scattered within a few hundred
meters of the site of the explosion
• The presence of damage to roads, structures, utilities, etc. complicating response
efforts
• Infrastructure contamination, including streets, sidewalks, sewers, etc.
Some of these do not affect radiation safety much, if at all. Most, however, require
that responders in the Hot Zone and any other areas affected by the attack be
aware of the potential concerns and take appropriate protective actions to avoid harm.
Workers at waste water treatment plants and those entering sewers downstream of
the area attacked, for example, will need to be taught to use radiation instruments
and to work safely in radiological areas until the sewers and treatment plants can be
surveyed and characterized.
Unlike an accident, a radiological attack is likely to result in the release of a greater
percentage of radioactive material from the source(s) used than would occur during
an accident. This means that radiation dose rates will be higher, more people might be
seriously affected, and the contamination is likely to affect a larger area than would
be the case in an accident. Thus, the Hot Zone is likely to be larger and concomitantly
more difficult to secure than was the case in Goiânia and other accidents. In addition,
responders must be aware of their accumulated radiation exposure as they work
to avoid exceeding a dose limit. It is also possible that the heat and pressure of
the explosion can cause physical and chemical changes to the radioactive materials
185
16.2 Radiation Safety Considerations Relevant
to a Radiological “Dirty Bomb” Interdiction
and Response
While there are a number of radiation safety practices that are common to a large
number, if not all, radiological circumstances, a radiological attack raises additional
issues. This is due, in part, to the fact that an accident involving the incidental
release of radioactivity is different than the malicious release of radioactivity with
the intent to cause harm. Consider: in 1987 an accident involving a 50.9 TBq Cs137 source resulted in four deaths, 120 individuals who required medical care, and
250 who required decontamination, and the cleanup created several thousand cubic
meters of radioactive waste [2]. Forty-four TBq, approximately 86% of the original
activity, of Cs-137 was recovered and accounted for. By comparison, a terrorist attack
would likely involve the malicious release of nearly 100% of the radioactive material.
Compared to a radiological accident, a terrorist attack is likely to involve:
• The release of a greater percentage of radioactivity from the source(s) used
• A larger contaminated area with contamination spreading further downwind
• Large amounts of airborne radioactivity during the initial release
• A wide variety of particle sizes due to heat and pressure from the blast
• Larger numbers of people with internal contamination due to absorption into
wounds, embedded fragments, and inhalation of airborne radioactivity
• Possible high-activity sources or source fragments scattered within a few hundred
meters of the site of the explosion
• The presence of damage to roads, structures, utilities, etc. complicating response
efforts
• Infrastructure contamination, including streets, sidewalks, sewers, etc.
Some of these do not affect radiation safety much, if at all. Most, however, require
that responders in the Hot Zone and any other areas affected by the attack be
aware of the potential concerns and take appropriate protective actions to avoid harm.
Workers at waste water treatment plants and those entering sewers downstream of
the area attacked, for example, will need to be taught to use radiation instruments
and to work safely in radiological areas until the sewers and treatment plants can be
surveyed and characterized.
Unlike an accident, a radiological attack is likely to result in the release of a greater
percentage of radioactive material from the source(s) used than would occur during
an accident. This means that radiation dose rates will be higher, more people might be
seriously affected, and the contamination is likely to affect a larger area than would
be the case in an accident. Thus, the Hot Zone is likely to be larger and concomitantly
more difficult to secure than was the case in Goiânia and other accidents. In addition,
responders must be aware of their accumulated radiation exposure as they work
to avoid exceeding a dose limit. It is also possible that the heat and pressure of
the explosion can cause physical and chemical changes to the radioactive materials