20.4 Decontamination of Buildings, Infrastructure, and Areas
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of the materials found in all of the types of buildings, homes, and workplaces of
which we can conceive.
A great deal of remediation is likely to consist of simply removing and disposing
of contaminated objects. It might not make sense, for example, to spend $500 in
materials and technician time to decontaminate a $50 hammer. Or, more likely, it
might not make sense to spend $100 million to decontaminate a building that can
be rebuilt for $10 million. In other cases it might make sense to gut a building,
removing and disposing of the ventilation system, carpets, fixtures, and furniture so
that the interior can be refurbished and refinished. Alternately, it might also make
sense to design a building ventilation system that, when it senses the introduction of
radioactive contamination, can shut down ventilation to avoid spreading it throughout
the building. Decisions such as these can have a substantial impact on the eventual
cost of decontamination and remediation.
If remediation of buildings is challenging, remediation outdoors is even more
so. One reason for this is the fact that so many natural surfaces are porous, making
decontamination difficult. The natural world also has a huge variety in types of
surfaces both living and non-living, with different physical and chemical properties
in each of these categories; consider the different properties of clay, loam, various
types of rock, gravel, tree bark, leaves, and so many more, each with different levels
of porosity and different depths to which contamination can penetrate.
On top of this, we must remember that the actual world is a combination of
natural and artificial so decontamination must be able to address, say, Cs-137 dust
on the surface of a glass window, nestled into the rough surface of a brick, adsorbed
onto clay minerals, taken up into plants, washed into the storm drains, resting in
the cracks between adjacent slabs of concrete, and all of the other variations that
can exist indoors and out. Radium, with different physical and chemical properties,
will behave differently than will cesium; cobalt and iridium are different yet, and
other radionuclides have their own unique properties. It is difficult, if not impossible,
to develop a decontamination plan for every physical and chemical form of every
radionuclide contaminating every type of surface or material.
Luckily, we have a great deal of experience in decontamination and remediation
and in general it makes little sense to develop nuclide- and surface-specific decontamination and remediation plans except for buildings or locations of significant
historic or cultural value. Soils can be dug up and replaced with clean soil, asphalt
and concrete streets and sidewalks can be removed, building exteriors can be sandblasted, and so forth—all making use of technologies and techniques that have been
developed and refined over several decades as well as whatever new techniques might
be developed for a specific circumstance. And, in fact, in many cases it might well
be less expensive and time-consuming to simply use an existing technology than to
spend time (and money) developing a less expensive and more efficient methodology,
given the time and expense of research and development.
Finally, as noted above, it will be necessary to decide whether or not some contamination might be better to leave in place. Contamination that is mechanically or
chemically attached to the surface of a high-rise building, civic monument, bridge
tower, or other tall structure tens or hundreds of meters above street level and that
253
of the materials found in all of the types of buildings, homes, and workplaces of
which we can conceive.
A great deal of remediation is likely to consist of simply removing and disposing
of contaminated objects. It might not make sense, for example, to spend $500 in
materials and technician time to decontaminate a $50 hammer. Or, more likely, it
might not make sense to spend $100 million to decontaminate a building that can
be rebuilt for $10 million. In other cases it might make sense to gut a building,
removing and disposing of the ventilation system, carpets, fixtures, and furniture so
that the interior can be refurbished and refinished. Alternately, it might also make
sense to design a building ventilation system that, when it senses the introduction of
radioactive contamination, can shut down ventilation to avoid spreading it throughout
the building. Decisions such as these can have a substantial impact on the eventual
cost of decontamination and remediation.
If remediation of buildings is challenging, remediation outdoors is even more
so. One reason for this is the fact that so many natural surfaces are porous, making
decontamination difficult. The natural world also has a huge variety in types of
surfaces both living and non-living, with different physical and chemical properties
in each of these categories; consider the different properties of clay, loam, various
types of rock, gravel, tree bark, leaves, and so many more, each with different levels
of porosity and different depths to which contamination can penetrate.
On top of this, we must remember that the actual world is a combination of
natural and artificial so decontamination must be able to address, say, Cs-137 dust
on the surface of a glass window, nestled into the rough surface of a brick, adsorbed
onto clay minerals, taken up into plants, washed into the storm drains, resting in
the cracks between adjacent slabs of concrete, and all of the other variations that
can exist indoors and out. Radium, with different physical and chemical properties,
will behave differently than will cesium; cobalt and iridium are different yet, and
other radionuclides have their own unique properties. It is difficult, if not impossible,
to develop a decontamination plan for every physical and chemical form of every
radionuclide contaminating every type of surface or material.
Luckily, we have a great deal of experience in decontamination and remediation
and in general it makes little sense to develop nuclide- and surface-specific decontamination and remediation plans except for buildings or locations of significant
historic or cultural value. Soils can be dug up and replaced with clean soil, asphalt
and concrete streets and sidewalks can be removed, building exteriors can be sandblasted, and so forth—all making use of technologies and techniques that have been
developed and refined over several decades as well as whatever new techniques might
be developed for a specific circumstance. And, in fact, in many cases it might well
be less expensive and time-consuming to simply use an existing technology than to
spend time (and money) developing a less expensive and more efficient methodology,
given the time and expense of research and development.
Finally, as noted above, it will be necessary to decide whether or not some contamination might be better to leave in place. Contamination that is mechanically or
chemically attached to the surface of a high-rise building, civic monument, bridge
tower, or other tall structure tens or hundreds of meters above street level and that