Talk about hazardous materials!
Radioactive technetium-99 (Tc-99) was
introduced to the K-25 uranium-processing
operations via “reactor returns” between 1953 and 1976. Isotopes of the material decay with a half-life of 211,000 years, even longer than the planning for most investment recovery and demolition projects! 
The Tc-99 caused issues with the production processes at the time and has since proved a nightmare in the decommissioning and demolition (D&D) campaign at K-25. The beta-emitting radioactive material exceeds most of the waste-disposal criteria at the CERCLA landfill in Oak Ridge and poses a huge expense if much of the massive rubble pile created by demolition has to be shipped to the Nevada Test Site or elsewhere for disposal. Jim Thiesing, vice president and K-25 project manager for Bechtel Jacobs Co., confirmed in March 2010, that there is no plan for BJC to do any more demolition work under the company’s current contract with the Department of Energy. Thiesing was among the speakers at a technical workshop on technetium-99 issues at K-25. The workshop attracted a full house at the American Museum of Science & Energy in Oak Ridge. 
The Bechtel Jacobs executive said the company plans to have K-25’s north end—which forms the bottom of the U— “demolition-ready” by the end of the contract except for stuff that remains stored in the building vaults. Much of the east wing of the building that’s not contaminated with technetium-99 will also be readied for demolition, except for sampling, “profile writing,” negotiation with environmental regulators, and foaming of equipment, he said. There will also be equipment—compressors and converters— stored in the vaults of the east wing that will have to be removed, he said. 
Thiesing and other speakers at the Oak Ridge workshop addressed issues associated with the Tc-99 contamination, which is pretty much dictating and dominating the plans to demolish K-25 and remove debris from the former uranium-enrichment site. According to information from workshop speakers, the primary concentration of technetium-99 is confined to a few units at the southeast section of K-25, but there apparently has been no agreement with regulators yet on what’s considered to be the Tc-99 area (which will have a whole different approach for demolition, to prevent the spread of the higher-radiation containing material).
Thiesing said that Bechtel Jacobs plans to spend the next year on preparations, using the federal money available to get ready for the demolition work ahead. “The reason we say that is if you look at the investment in getting the building ready, it’s about 85 to 90 percent of the manpower and  dollar expenditure. The demolition—at least on the west, north, and non-Tc-99 east—is only about 10 to 15 percent. And that ratio will hold in the Tc-99 contaminated area,” he said. “Most of the resource investment is getting it ready.” Getting it down is really pretty easy. It’s obviously going to be harder in the techmetium contaminated area, but still pretty easy once the preparation is complete.”
Adapted from numerous articles
in The Atomic Underground by
Frank Muger, Senior Writer of
the Knoxville News Sentinel.