The interesting article by David Clark, David Janecky, and Leonard Lane (Physics Today September 2006, page 34) about the cleanup at Rocky Flats noted advances in understanding radioactivity migration and pointed to a high level of stakeholder participation in planning. However, it also raised some questions for me.
Were percolation tests done to check the isolation of deep groundwater from the top 30 meters? The presence of what the authors call “highly impermeable bedrock” between the deep and shallow waters could be expected to protect the deep water table, but was it checked? The authors say, “Approximately 90 percent of the radioactive inventory was in the top 12 cm of the soil.” They also state that “the work focused on removing soil contaminated … down to one meter below the surface, and replacing it with fresh soil; soil contaminated at depths greater than one meter was allowed to remain in place, even at higher concentrations. To decontaminate the concrete walls of buildings, workers used a variety of techniques.” I believe it was implied that the 903 Pad was demolished and the fragments removed along with the chemical drums that sat on it. How geographically dense were the post-remediation soil samples in the pad area and downstream of it?
The article also mentioned that some control measures will require regular maintenance. How long? Ten half-lives of plutonium? Who is in charge of it, and who is paying for it?
How were the removals disposed of? Were they encapsulated? Are they secure from natural and human influence? Did the stakeholders understand and have any influence on the methods used and the final disposal? If so, I would agree with the authors that the full involvement and sign-off of stakeholders are a key advance in dealing with the problems involved with such a difficult undertaking. It is striking that the Yucca Mountain nuclear waste storage facility has not yet been able to get the agreement of its stakeholders after a much longer passage of time.
