Specks of radioactive contamination have been found on eight cars or other vehicles that were parked at the Hanford nuclear reservation’s Plutonium Finishing Plant.
Two of the vehicles may have been contaminated before they were driven home by workers during the weekend, according to information released to Hanford employees Tuesday afternoon. The owners of those cars have been offered radiation surveys of their homes.
Demolition remains on hold at the plant — with just a few weeks of work left — after the spread of radioactive contamination in recent days outside zones around demolition areas, where contamination was expected to be contained.
About 100 vehicles were surveyed before leaving the plant complex Monday night, with surveys finding radioactive contamination on four government vehicles and four vehicles owned by workers, according to Department of Energy contractor CH2M Hill Plateau Remediation Co.
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Earlier in the day, just two vehicles were believed to be contaminated.
Contamination also was found inside one of the government vehicles.
The eight vehicles were being decontaminated Tuesday, with some already cleaned and released to their owners Monday.
The contamination was found Friday night after demolition had been completed at the plant’s Plutonium Reclamation Facility.
A stop-work order then was issued Sunday by CH2M officials.
No demolition had been planned over the weekend.
However, work went ahead as planned Sunday to finish stabilizing the rubble left from Friday’s demolition, said Tom Bratvold, project vice president for CH2M.
About half of the rubble pile still needed to be covered with soil to prevent a possible spread of contamination.
Soil cement also was used on the rubble pile.
A Sunday night windstorm swept through the area, and more specks of radioactive contamination were found Monday in areas that previously had been found to be clean, officials said.
One of the spots was found on the asphalt outside the plant’s shift office, which has lots of worker foot traffic.
Workers were told to stay in the trailers used as offices until the area could be surveyed for radioactive contamination, according to CH2M. The last of the employees were allowed to leave the offices at 6:30 p.m.
Washington State Department of Health employees are conducting independent checks for the spread of radioactive contamination from the Hanford Plutonium Finishing Plant.
It was not considered a “take cover” order, Bratvold said.
Take cover orders are issued when there is a threat of airborne contamination and requires steps like shutting off ventilation and closing windows to protect workers from possibly contaminated air.
No radioactive contamination was found inside the office trailers or on the workers leaving the trailers Monday night.
However, the radiological control technician who found the contamination outside the plant’s shift office had contamination on his boot, Bratvold said.
The Washington Department of Health was doing its own surveying related to the contamination spread this week.
State employees collected air and surface soil samples Tuesday, including near Highway 240.
An air sample collected June 8 at the Rattlesnake Barricade security entrance to Hanford off Highway 240 was found to have a very low level of radioactive contamination. The plant, three miles away, had a contamination spread the same day.
Laboratory results on samples collected by state workers this week will not be available for about 30 days.
State employees also were using instruments to survey for radiation.
By mid-afternoon they had not found any radiation above normal background levels, said John Martell, manager of the Radioactive Air Emissions Section of the Department of Health Office of Radiation Protection.
The focus of work Tuesday by Hanford employees at the Plutonium Finishing Plant continued to be on surveying for contamination and containing any found around the plant.
Any specks of contamination were being covered with soil cement to keep them from becoming airborne, Hanford workers were told in a message.
Demolition work had resumed Friday after a two-day stop work order had been lifted.
CH2M called a halt to demolition work and a worker at the site also used his authority to call a stop to work Dec. 13. Concerns were raised when lapel air monitors worn by several workers tested positive for radioactive contamination in two areas well away from the demolition site.
After the stop work order was called Dec. 13, some specks of radioactive contamination were found, including on a concrete slab and a man lift basket near the south fence of the plant site.
The findings included contamination just beyond the fence line, but in an area used only by plant workers, according to Hanford officials.
Demolition was allowed to resume with the completion of the tear down of the plant’s reclamation facility, the area of the plant believed to have the most contamination.
After the spread of contamination was found as part of an end-of-work check Friday night, Doug Shoop, the manager of the DOE Hanford Richland Operations Office, and Ty Blackford, the president of CH2M at Hanford, had a lengthy discussion.
Blackford followed up with a letter Monday saying that the demolition risks for the remainder of the Plutonium Finishing Plant continue to be significant.
CH2M plans to expand the control zone around the Plutonium Finishing Plant demolition area for the third time after the most recent spread of radioactive contamination.
The part of the plant remaining standing had two processing lines where plutonium was converted into pucks to be shipped to the nation’s nuclear weapons manufacturing plants.
CH2M planned to delay loading out the demolition rubble pile at the plant to prevent any increased risk or interference as the remainder of the plant is demolished. Workers also will be moved to offices farther away before the rubble is loaded.
The control boundary around the demolition area will be expanded again.
The boundary was expanded after the June 8 contamination spread and again after worker air monitors tested positive for airborne contamination earlier this month.
The expanded boundaries could affect some other activities at Hanford, Blackford said. CH2M will coordinate the demolition schedule to allow safe access to other projects, he said.
The changes will extend the site stabilization schedule, but it is imperative that the project be completed safely, Blackford said.
Shoop sent a letter in reply saying that that plan was reasonable, but he requested a briefing before allowing CH2M to proceed with other activities.