Demolition is well under way for one of the world’s largest buildings—constructed as a uranium enrichment facility as part of the supersecret Manhattan Project during World War II. It continued to serve that purpose throughout the Cold War. The massive, U-shaped, four-story building, code named “K-25”, measured a mile long by 1,000 feet. It took a little over 18 months to construct between mid- 1943 and early 1945 amid the race for the first atomic bomb. Six decades later… The code name of K-25 for this massive Manhattan Project facility was a combination of the “K” from the Kellex Corporation, the initial contractors of the plant, and a World War II–era code designation for uranium-235.
Completed in early 1945 at a cost of $512 million (equivalent to $6.2 billion in current dollars), the K-25 plant employed 12,000 workers and required upwards of 25,000 to build. The timeline was so critical that construction began even before development of the design for the uranium enrichment process was finalized. Due to construction needs at K-25 and elsewhere on the Oak Ridge, Tennessee government reservation, the town of Oak Ridge, originally designed for 13,000 people, grew to 50,000 by the summer of 1944. The tens of thousands needed for the construction of K-25 lived nearby, in a community built by the Army in 1943 that came to be known as “Happy Valley.” 
The K-25 plant, located on the southwestern end of the Oak Ridge reservation, used the gaseous diffusion method to separate uranium-235 from uranium-238. Gaseous diffusion is based on the principle that molecules of a lighter isotope would pass through a porous barrier more readily than molecules of a heavier one. It requires myriads of repetitions, in which a gas increasingly rich in uranium-235 (the lighter molecule) was separated out from uranium-238 (the heavier molecule). This process required hundreds of boxcar-size machines using a system of barriers, called “cascades.” Although producing minute amounts of final product measured in grams, gaseous diffusion required a massive facility to house the hundreds of cascades and required enormous amounts of electric power. In fact, K- 25 consumed one-tenth of the entire nation’s electrical output at one point. 
Gaseous diffusion was one of three isotope separation processes that provided uranium-235 for the Hiroshima weapon (Little Boy)—the other two being electromagnetic separation and liquid thermal diffusion. The S-50 liquid thermal diffusion plant, using convection to separate the isotopes in thousands of tall columns, was built next to the K-25 power plant, which provided the necessary steam. Much less efficient than K-25, the S-50 plant was torn down after the war. Gaseous diffusion was the only uranium enrichment process used during the Cold War. K-25 was the prototype for later Oak Ridge plants and those at Paducah, Kentucky, and Portsmouth, 

In the postwar years, additional uranium enrichment facilities were built adjacent to K-25, forming a complex officially known as the Oak Ridge Gaseous Diffusion Plant and commonly called the “K-25 site.” Uranium enrichment operations at the K-25 site ceased in 1987. More than 850 workers  will be involved in the demolition. 
Demolition Underway. Bechtel Jacobs Co. and its subcontractors were the initial recipients of the demolition project, beginning with the west wing of the 40-plus acre facility. They have demolished most of the U-shaped K-25 building’s west wing, but the east wing and north tower are considered to be more challenging. A DOE official says it is doubtful Bechtel Jacobs will complete the demolition by the end of 2011, when its contract expires. The work has been delayed on multiple occasions because of safety issues or technical concerns, and some aspects of the project were complicated by the deteriorated condition of the 65-year-old building. As of mid-2009, the demolition work had generated more than 9,200 truckloads of contaminated debris, all of which is being shipped to DOE’s nuclear landfill about seven miles away from the K-25 work site. In addition to that demolition debris, thousands of compressors and converters are being transported to the site for disposal. 
Surplus Equipment. According to a company release from Bechtel Jacobs, the DOE environmental cleanup contractor for Oak Ridge, material that was removed beginning in 2003 that was not directly involved in the uranium enrichment process included: office furniture, such as desks, chairs, tables, and file cabinets; scrap metal, scrap wood, and wooden pallets; broken-down equipment, such as forklifts, manlifts; and welding machines; drums of chemicals, and electrical equipment, such as wire, power panels, and light fixtures. It is estimated that nearly 15,400 cubic yards of material were removed and disposed of under this contract. A number of issues must be resolved before demolition resumes on the north end, which forms the bottom of the “U” and the east wing. Those include a decision on how to deal with parts of the building contaminated with highly radioactive technetium-99, and what contractor will carry out the rest of the work.
Last year, DOE extended and modified the BJC contract, valued at $1.48 billion, to allow the contractor to finish work on the mile-long and massively contaminated building that once processed uranium for the nation’s Cold War arsenal of nuclear weapons. The demolition project, however, has turned out to be even more difficult than envisioned, and DOE and Bechtel Jacobs, in concert with environmental regulators, are still trying to figure out the best way to safely take down the World War II-era building. DOE does not plan to extend the Bechtel Jacobs contract again, and Boyd said federal staff members are reviewing cost estimates and evaluating contract options for completing the K-25 project and doing other work at the Oak Ridge site. Boyd said DOE intends to have another contractor in place by the end of Bechtel Jacobs’ contract so the workforce can be transferred and  continue the K-25 work. “DOE is in the process of evaluating proposals we have submitted regarding the path forward on K-25,” Hill said. He said the contractor is making “steady progress” on the west wing and getting the non- technetium areas of the east and north ready for demolition. A separate strategy is under development for parts of the building where radioactive technetium is in process equipment.
That equipment will have to be segregated and probably shipped to the Nevada Test Site for disposal. Federal officials have not yet said when they plan to release the “request for proposals,” but they described some of the Oak Ridge projects expected to be part of the scope of work. The new contractor will succeed Bechtel Jacobs Co., DOE’s  environmental manager since 1998, with the transition expected to take place before July 1, 2011. The hazards will range from radioactive materials to asbestos to PCB oils. 
Complex Problems. The wartime rush to build the plant apparently led to shortcuts. A concrete floor on the fourth level was so thin a demolition worker fell through in 2006. He survived, but everyone else now working more than six feet off the ground must wear a safety harness. No heat, no air-conditioning, a rats’ nest of electrical wiring, and a crumbling support system—those are just some of the problems the 820 workers on the job have encountered. Often repairs must be made so demolition can proceed. “I would say it is a difficult work environment,” Kelly Trice, the project manager with cleanup contractor Bechtel Jacobs Co., acknowledged during a recent tour. “We do our best with it, but it is a hazardous job.” Though gaseous diffusion is fast becoming outdated by more efficient centrifuge technology, the old
K-25 barriers continue to have some value, at least to  national security. Federal agents arrested a K-25 janitor last year on allegations of trying to sell barrier parts to the French government. K-25 demolition is one of the most complex decommissioning projects in the country because of its size and enriched uranium operations, and contamination and structural problems. Among other things, crews have had to inject foam material into equipment and piping to immobilize some residual low-level uranium and remove so-called high-risk components. 
Historic preservation. Some Manhattan Project veterans and enthusiasts consider K-25 a national treasure worth preserving. DOE continues to study whether to spare the bottom of the U, or North Tower, for public tours. “There are several factors that have to be taken into account,” Brown said. “One is we are not going to spend more money on it than it would take to tear it down. And secondly and overwhelmingly, we are not going to put people’s lives at risk.”
DOE, at the urging of preservationists and others, including the Tennessee congressional delegation, is taking another look at salvaging a piece of the milelong, U-shaped K-25 plant. The west wing of K-25 has already been demolished, and DOE officials repeatedly stated over the past year and a half that the remaining structure had become so deteriorated it was unsafe and uneconomical to save even a section—as promised in a 2005 memorandum of agreement. DOE has now hired an independent engineering firm to assess the structural integrity of what’s left. The federal agency has also hired Mac West, a Washington, D.C., consultant, to evaluate possibilities and priorities for interpreting history—not just at K-25 but Oak Ridge in its entirety.
‘’The Oak Ridge story is a vital part of a much larger story that has to do with the initiation of the Atomic Age,” West, a former science museum director, said in a telephone interview. “Yes, the idea was to win World War II, and that, in and of itself, is a remarkable story. But the ongoing
impact of what was and is continuing to be learned at Oak Ridge has really affected all of us in ways that most don’t understand.” The consultant was to have met with a structural engineer hired by DOE in mid- June to take an up-close look at K-25. West’s report to DOE is due in a few weeks. He said he’ll evaluate what’s important and what’s feasible in presenting and interpreting Oak Ridge history, and the options will be ranked in some way. Many see preservation as a way to bolster heritage tourism in Oak Ridge.
Such adaptive reuse is why some are placing such importance on saving part of K-25, even if it’s just a small chunk of what was—at the time of its completion in 1945— the largest building in the world. Oak Ridge historian Bill Wilcox said one option, known as Option K, has the support of DOE and would include an interpretive history center at the site, preserve the 85 acres on which the 44-acre building was situated, restore one of the original security portals, and install a new viewing tower.
Reprinted from ASSET 2.0, the Investment Recovery Business Journal, Vol. 4, 2010

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