SANDUSKY - Residents who live in the vicinity of Sandusky's Plum Brook should know by late April where most of the creek's radioactive secrets lie.
But not all of them.
A NASA official told The Blade yesterday that the space agency has not been able to determine the end point of the contamination caused by its mothballed Plum Brook nuclear test reactor more than 33 years ago, despite months of sampling.
Sampling will soon be extended from State Rt. 250 to State Rt. 2, Keith Peecook, a senior NASA engineer overseeing the site investigation, said.
Although particles of radioactive Cesium 137 and Cobalt 60 that escaped from the NASA site prior to its 1973 shutdown have now decayed to barely detectable levels, Mr. Peecook said he believes some of them probably migrated out to Lake Erie during heavy storms.
"It's certainly possible," he said.
Plum Brook is one of the lake's smallest tributaries, emptying into the Sandusky Bay in Erie County's Huron Township.
It wouldn't be the only time radioactive material has gotten into the Great Lakes.
After a multimillion dollar fire inside Detroit Edison Co.'s Fermi II nuclear plant on Christmas Day, 1993, thousands of gallons of water that firefighters used to extinguish the blaze gradually was discharged into western Lake Erie.
Jan Strasma, a spokesman for the Nuclear Regulatory Commission, said many nuclear plants discharge wastewater with trace amounts of radiation during normal plant operations.
But those releases, highly regulated and governed by federal discharge permits, are considered small enough to be inconsequential.
Nobody knows how much radioactive material was released from NASA's Plum Brook Station.
The contamination, believed to have stemmed from a pinhole leak that was never detected while the plant operated between 1961 and 1973, wasn't documented until the fall of 2005.
More than 1,000 sediment samples have been drawn from Plum Brook's creek bed and its banks, from the NASA property lines to Route 250.
Results are still being tabulated. The goal is to finish that task by mid-April, then go over the figures with area residents and government regulators, Mr. Peecook said.
He said the contamination does not appear to be uniformly spread. There are spotty elevations, though nothing the Ohio Department of Health considers a public health threat.
The state health department, which has been doing concurrent lab analyses, believes the risk of exposure is minimal, Bret Atkins, a department spokesman, said.
Mr. Peecook said he wants affected property owners to have results in advance of a community workgroup meeting scheduled for 7 p.m. on April 25 at the EHOVE Career Center in Milan, Ohio.
NASA is bringing in a hydrogeologist to study the historic patterns of Plum Brook's water flow, especially from major storm events that temporarily have raised the creek's water level and increased its current. That research will be used to help estimate how far apart the radioactive particles scattered, Mr. Peecook said.
He said he expects to propose targeted soil removal from spots along the creekbed and banks that have elevated numbers. "There would be no reason to go in there and do a large-scale dredging of Plum Brook," he said.
The NRC has told NASA that the space agency's decommissioning obligation won't be completed until it finishes any cleanup that is ordered.
NASA's Plum Brook test reactor was built in 1958 at a cost of $15 million. Its last estimate for decommissioning was $160 million, but Mr. Peecook has said that figure has grown by millions in recent years. The reactor was once one of America's 10 largest for nuclear research, with a focus on nuclear-powered rocket propulsion.
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