130
13 Developing a Radiological and Nuclear Interdiction Network
handheld PRDs, on the other hand, are very good at identifying the precise location of a radioactive source but are not nearly as sensitive as the large-volume aerial
detectors and cannot survey large areas nearly as quickly. Aerial detectors are also
able to surmount many obstacles that would slow or prevent an effective survey on
the ground—walls, ravines, un-bridged rivers, confusing mazes of streets, and the
like.
Thus, an effective interdiction plan will use aerial detectors to quickly survey large
areas and long lengths of highway, conveying the location of any “hits” to teams on
the ground who can localize the source using their hand-held detectors. Additional
instruments (waterborne, vehicular, drone-mounted, and so forth) can be added to
the interdiction effort as they become available.
While the initial interdiction efforts are taking place, the interdiction team(s) can
begin to identify (if this has not already been done) choke points at which to establish
screening stations. These would include bridges and tunnels through which traffic is
funneled—all traffic into Manhattan, for example, must come through one of three
tunnels or across one of sixteen bridges; if Manhattan is thought to be a target, it can
be far easier to secure fewer than twenty crossings than to try to secure hundreds
or thousands of large and small roads across thousands of square kilometers. The
problem with concentrating on these final chokepoints, however, is that they are all
at the periphery of the assumed target; these should be the last in a series of barriers
rather than comprising the primary defense against an attack. Accordingly, it makes
sense for interdiction efforts to include chokepoints that are further away from the
presumed targets; toll road entrance and exit ramps, toll plazas (although the advent
of high-speed cashless tolling stations reduces the efficacy of these locations), service
areas (especially on limited-access roads), major bridges, and the like.
In addition to taking measures to interdict the stolen materials while they are in
transit to the target, the potential target cities can begin to establish their own interdiction networks. These will likely involve the use of the same types of instruments
that are being deployed for the large-scale interdiction efforts—at least, up to the
capabilities of the various cities.
Establishing an interdiction network within a city, to protect critical infrastructure,
an iconic location, or a special event, is similar to the process described above,
although there are some differences. The primary difference, of course, is that there
is no time pressure, with the corollary being that the network might have to operate
for extended periods of time—for days, weeks, or even years. New York City, for
example, has been managing radiological interdiction networks for major events (e.g.
Time Square at New Year’s Eve, the United Nations General Assembly, and many
others) every year since 2003 and have been conducting radiological interdiction
surveys on a routine basis since before 2010.
Another difference between monitoring a city for radioactive sources originating
within the city is that the target city is known; it is not likely that a terrorist group
would steal a source from a hospital in New York City to use in an attack against
Philadelphia. Any one city has a limited number of high-activity sources that tend
to be in fixed locations; such sources are easier to secure against theft, and those
who own these sources are able to work with law enforcement agencies to determine
13 Developing a Radiological and Nuclear Interdiction Network
handheld PRDs, on the other hand, are very good at identifying the precise location of a radioactive source but are not nearly as sensitive as the large-volume aerial
detectors and cannot survey large areas nearly as quickly. Aerial detectors are also
able to surmount many obstacles that would slow or prevent an effective survey on
the ground—walls, ravines, un-bridged rivers, confusing mazes of streets, and the
like.
Thus, an effective interdiction plan will use aerial detectors to quickly survey large
areas and long lengths of highway, conveying the location of any “hits” to teams on
the ground who can localize the source using their hand-held detectors. Additional
instruments (waterborne, vehicular, drone-mounted, and so forth) can be added to
the interdiction effort as they become available.
While the initial interdiction efforts are taking place, the interdiction team(s) can
begin to identify (if this has not already been done) choke points at which to establish
screening stations. These would include bridges and tunnels through which traffic is
funneled—all traffic into Manhattan, for example, must come through one of three
tunnels or across one of sixteen bridges; if Manhattan is thought to be a target, it can
be far easier to secure fewer than twenty crossings than to try to secure hundreds
or thousands of large and small roads across thousands of square kilometers. The
problem with concentrating on these final chokepoints, however, is that they are all
at the periphery of the assumed target; these should be the last in a series of barriers
rather than comprising the primary defense against an attack. Accordingly, it makes
sense for interdiction efforts to include chokepoints that are further away from the
presumed targets; toll road entrance and exit ramps, toll plazas (although the advent
of high-speed cashless tolling stations reduces the efficacy of these locations), service
areas (especially on limited-access roads), major bridges, and the like.
In addition to taking measures to interdict the stolen materials while they are in
transit to the target, the potential target cities can begin to establish their own interdiction networks. These will likely involve the use of the same types of instruments
that are being deployed for the large-scale interdiction efforts—at least, up to the
capabilities of the various cities.
Establishing an interdiction network within a city, to protect critical infrastructure,
an iconic location, or a special event, is similar to the process described above,
although there are some differences. The primary difference, of course, is that there
is no time pressure, with the corollary being that the network might have to operate
for extended periods of time—for days, weeks, or even years. New York City, for
example, has been managing radiological interdiction networks for major events (e.g.
Time Square at New Year’s Eve, the United Nations General Assembly, and many
others) every year since 2003 and have been conducting radiological interdiction
surveys on a routine basis since before 2010.
Another difference between monitoring a city for radioactive sources originating
within the city is that the target city is known; it is not likely that a terrorist group
would steal a source from a hospital in New York City to use in an attack against
Philadelphia. Any one city has a limited number of high-activity sources that tend
to be in fixed locations; such sources are easier to secure against theft, and those
who own these sources are able to work with law enforcement agencies to determine