Bechtel adds safety monitors
By Bill Bartleman
Bechtel Jacobs Co. ordered 25 employees of a private contractor working at the Paducah Gaseous Diffusion Plant to begin wearing radiation monitoring devices after it was determined they were being exposed to higher levels of radiation than was indicated in earlier tests.
The higher exposure level was found Monday during testing that was done for the U.S. Department of Energy's Headquarters Oversight Investigative Team, which is looking into allegations contained in a workers' lawsuit that alleged that former operators of the plant falsified documents regarding the disposal of contaminated waste and records regarding environmental contamination at the plant.
Jimmy Massey, environmental site manager for Bechtel Jacobs, said the exposure level detected Monday does not pose a health risk for the workers, but it is above limits established by Bechtel Jacobs and DOE that require wearing personal monitoring devices. The order to begin wearing the dosimeter monitors was issued Tuesday.
Massey said the question he wants answered is why two earlier tests by his company indicated that the potential exposure was below levels that require monitoring. He said an investigation has been started to answer that question.
Massey said workers employed by MACTEC of Golden, Colo., are building a new concrete storage yard for steel cylinders that contain depleted uranium hexafluoride, the material left after Uranium-235 is enriched into fuel for nuclear power plants. He said the radiation is the result of gamma rays emitting from the cylinders.
The new cylinder storage yard is located in front of the plant and not far from its main access road.
Regulations require that anyone at the plant who has a potential exposure of more than 100 millirems of radiation per year must wear a dosimeter, a radiation measuring device. Massey said the monitoring level is far below the exposure limit of 5,000 millirems per year, set by the U.S. Environmental Protection Agency.
The cumulative dosimeter readings are kept for each person exposed, and anyone who receives more than 2,000 millirems within a year is reassigned to an area that would not subject them to the 5,000-millirem limit, Massey said.
Bechtel Jacobs' tests conducted April 22 and June 24 indicated that workers involved in the construction would not reach the 100 millirem threshold, Massey said. Construction began in May and should be completed in December.
"Physically, nothing has changed since April and June to explain the discrepancy," Massey said. "We messed up somehow ... and now the issue is to understand the reason for the discrepancy."
Bechtel Jacobs is the private contractor hired by the Energy Department to coordinate cleanup activities and manage existing waste at the plant.
There are almost 37,000 cylinders at the Paducah plant, each containing nine to 12 metric tons of depleted uranium hexafluoride. DOE will accept proposals later this year for recycling the material into some other nuclear substance or for use as a heavy metal. The concrete yards are being built to prevent potential soil contamination if any of the cylinders leaks.
Energy Secretary Bill Richardson ordered an investigation of the plant last month after the suit was filed.
A team of more than 20 DOE officials arrived at the plant Aug. 23 to gather data and review records related to plant operations since 1990. The team is expected to complete on-site work this week and then compile a report of its findings that could be issued next month.
One of the tasks of the group is to review the plant's current practices. As part of that job, they asked to tour the cylinder construction site and take readings of radioactivity. "The readings indicated the potential exposure in excess of 100 millirems," Massey said. "That doesn't mean they were exposed to that level ... just the potential ... and that is different than previous tests showed.
"We will take a look at ourselves and find out how it happened."
He said there were no plans to conduct medical tests or medical screening of the employees since the levels are so low and there was no direct exposure to the radioactive material. "It is from the gamma rays coming from the cylinders," he said.
According to documents prepared by the Energy Department, the average person will be exposed to 300 millirems a year from natural background radiation. By comparison, a person who has an upper gastrointestinal diagnostic X-ray series would receive 244 millirems.