[ RadSafe ] Secret nuclear find revealed - Highly radioactive material found in 2005 at Oak Ridge junkyard moved to safe site
andrewsjp at chartertn.net
Sat Dec 30 23:01:27 CST 2006
Susan Gawarecki wrote:
> Secret nuclear find revealed - Highly radioactive material found in
> 2005 at Oak Ridge junkyard moved to safe site
> By FRANK MUNGER, munger at knews.com
> December 25, 2006
> OAK RIDGE - Inside the fences of a Cold War junkyard, with
> contaminated scrap stacked in mountainous piles across 30 acres,
> cleanup workers were told to expect the unexpected.
> But nobody expected this - three unmarked casks containing thousands
> of curies of radioactive cesium-137. "It was a total surprise," said
> John Lea of Bechtel Jacobs Co., the government's cleanup manager in
> Oak Ridge.
> Cesium-137 is a product of nuclear fission that's created in reactors.
> It is used in lots of radiation equipment, ranging from medical
> therapy units that treat cancer to well-logging instruments in the oil
> industry. It also is considered an optimum material for radiological
> dispersal devices - so-called dirty bombs - and therefore coveted by
> Oak Ridge National Laboratory officials were told the three casks
> contained about 10,000 curies of cesium and strontium-90, another
> fission product, said Tim Powers, a manager at ORNL.
> John Owsley of the Tennessee Department of Environment and
> Conservation said state officials were told that one of the casks
> contained more than 200,000 curies of cesium, with lesser amounts in
> the other two casks. "That is a significant amount of material," he
> said. "It is unusual to find something of this magnitude." A curie is
> unit of measure used to describe the amount of radioactivity in
> material. Owsley said state officials more typically deal with cesium
> in picocuries as found in the environment. A picocurie is a trillionth
> of a curie.
> Oak Ridge authorities are unable to explain how the cesium, especially
> such a huge source of radioactivity, got into a scrap yard devoted
> mostly to discards from the former K-25 uranium-enrichment plant. "We
> have no idea," Lea said. Efforts to track the origin of the highly
> radioactive materials or their lead-lined containers were
> unsuccessful, he said.
> Workers reportedly identified the first of the cesium-bearing casks in
> October 2005 as they surveyed a truckload of scrap ready to leave the
> site on the way to a nuclear landfill several miles away.
> Radiation-detection equipment picked up abnormally high readings. Two
> similar casks were found later at the bottom of a big pile containing
> about 1,600 tons of scrap, Lea said.
> Bechtel Jacobs officials revealed the find to the News Sentinel during
> a recent briefing and tour of the scrap yard, which is now in the
> final stages of cleanup. After the load of cesium was discovered in
> late 2005, officials upped security at the scrap yard, which is a
> couple of miles west of K-25, now known as the East Tennessee
> Technology Park. "That's not normally a very secure site," said Dennis
> Hill, a spokesman for Bechtel Jacobs. Steps were taken to restrict
> access until the materials could be transferred to a safe storage site
> at ORNL, he said. The transfer took about six months to complete
> because of required safety plans and other preparations, he said.
> It's still not clear how much cesium is contained in the rusty casks,
> which may have been sitting outdoors for decades. Bechtel Jacobs
> officials said an initial evaluation, using "nondestructive assay"
> techniques, indicated there were thousands of curies of cesium-137.
> They declined to be more specific. Powers said nuclear experts would
> conduct a comprehensive examination of the contents sometime this
> winter. That work will involve taking samples from the casks to
> identify the radioisotopes present and to provide the detailed
> information necessary for disposal, he said. Powers said UT-Battelle,
> the contractor that manages ORNL, does not yet have custody of the
> casks. They are being stored at a Bechtel Jacobs facility at the
> laboratory, he said.
> Most of the scrap was dumped at the storage yard in the 1950s and
> 1960s. If that was true of the cesium casks, that means the
> radioactivity back then was more than double what it is today.
> Cesium-137 has a half-life of 30 years, which means that half of an
> amount would decay in that period.
> The potential danger of untended cesium is well documented. In 1987,
> at Goiania, Brazil, four people died of radiation poisoning and
> hundreds of others were contaminated after an abandoned radiation
> therapy source fell into curious hands. The glowing cesium inside the
> capsule fascinated villagers, who shared the mysterious stuff with
> their friends, used it for jewelry and even smeared it on their
> bodies. The cesium source at Goiania was reported to be 1,375 curies.
> TDEC officials were told of the Oak Ridge cesium discovery last year
> but were sworn to secrecy. "I was informed there was a security
> concern with the material being stored on site and not until the
> material was in a secure place was I to discuss it. Our role is
> environmental, and, basically, we do what we're told when security is
> concerned," Owsley said. "The manner they chose to deal with security
> was through secrecy."
> The scrap-yard finding elevated the state's concerns about what may be
> in some of the Oak Ridge waste sites, Owsley said. In some cases,
> disposal or storage records don't exist, and in other cases, they are
> simply inadequate, he said. The state used the incident to emphasize
> the need for closer monitoring, Owsley said.
> Following the discovery, cleanup workers constructed a new concrete
> pad at the scrap yard to do additional sorting of materials prior to
> loading the trucks, Lea said. Washington Safety Management Solutions
> is doing the cleanup under a $16.9 million subcontract with Bechtel
> Jacobs. The project began in May 2004, and more than 45,600 tons of
> contaminated materials have been removed from the area, known
> officially as the K-770 Scrap Yard. The cleanup project has required
> thousands of truck shipments from the scrap yard to the government's
> nuclear landfill. The disposal cells have multiple liners to prevent
> leaks into the environment.
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The photo of the three casks in the Knoxville News Sentinel, or was it
the Farragut Press, showed three very large casks, not particularly
rusted, but certainly old, in a shed overgrown with weeds and small
trees. The casks were undamaged. Turns out that they contained old
resin from which the Cs-137 had been eluted years ago when Oak Ridge
was actively preparing sources of this nuclide. The current contents is
the residue following the elution. In the photo the casks were posted
as a high radiation area, etc. The posting was new. Sort of an unusual
situation, but not an eminent danger in my opinion.
John Andrews, Knoxville, Tennessee
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