[ RadSafe ] Secret nuclear find revealed - Highly radioactive material found in 2005 at Oak Ridge junkyard moved to safe site

[Susan Gawarecki]

Secret nuclear find revealed - Highly radioactive material found in 2005 
at Oak Ridge junkyard moved to safe site
http://www.knoxnews.com/kns/local_news/article/0,1406,KNS_347_5236518,00.html
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 terrorists.

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.