A difficult cleanup of a Hanford research laboratory near Richland and the Columbia River suffered setbacks this spring as some contamination was not the type expected, spread farther than anticipated and was found on a worker’s personal clothing, according to incident reports published by the Defense Nuclear Facilities Safety Board.
The contamination of the contract worker’s clothes involved strontium, and was detected March 28 as he left a radiological area of the shuttered research laboratory known as the 324 Building.
The source of the strontium, which was removed from the clothing with a piece of tape, was not identified. The incident triggered a stop-work order April 1, which was lifted April 4 when no additional contamination was detected, according to the federal Energy Department, which manages the Hanford site in South Central Washington.
In a statement this month, Energy Department spokesman Geoffrey Tyree, said the department has a careful and deliberate work plan in place to clean up the building site. “This plan includes a continual review of safety protocols as the mission evolves and the workforce continues to make progress on this project,” Tyree said.
Tom Carpenter, executive director of the watchdog group Hanford Challenge, questioned why the problems were not disclosed earlier.
“This is a very sensitive site due to its location,” said Carpenter, who noted the 324 Building is less than 2 miles north of Richland.
Hanford once produced plutonium for bombs, and is now considered the most polluted nuclear site in North America. Cleanup is projected to continue for decades at a cost of more than $300 billion. And the yearslong effort to demolish the 324 Building demonstrates the technological obstacles and hazards that can be encountered in this work.
The building was used for research involving highly radioactive materials, including tests on how to try to stabilize these materials for long-term storage. The three-story laboratory operations, encompassing 102,000 square feet, opened in 1965 and ceased operating in 1996. During those years, researchers used “hot cell” containers with leaded glass windows that enabled them to work with hazardous wastes without being exposed to radiation.
Workers, when they prepared to take down the building a decade ago discovered that radioactive material had leaked into the soil, contaminating an area up to 6 feet in depth that is located some 300 yards from the Columbia River. This greatly increased the complexity of the cleanup, which was put on hold in 2010 as studies were launched to develop a new approach.
Eventually, a plan was developed that calls for fortifying the building’s foundation, so that it will remain stable while this soil is excavated, according to the contractor CH2m Hill Plateau Remediation Co. Since radiation levels are so high, remote-operated equipment must be used to remove the contaminated soil.
The work to clean up the building has now resumed, with crews in recent months attempting to drill holes for the installation of cameras to help do the work.
In a statement last week, Energy Department spokesman Geoffrey Tyree said the department has a careful and deliberate work plan in place to clean up the site. “This plan includes a continual review of safety protocols as the mission evolves and the workforce continues to make progress on this project,” Tyree said.
The cleanup problems the crews encountered this year have been documented in a series of inspection briefs posted online by the Defense Nuclear Facilities Safety Board, which conducts independent oversight of federal Energy Department nuclear sites. They also were reported this month in The Energy Daily.
In a March 15 report, Defense Facilities Board inspectors said that contamination March 13 unexpectedly spread beyond drilling equipment, causing a pause in the cleanup while workers left the area.
In a March 29 report, the inspectors wrote that efforts to install the camera again stopped when surveys “discovered contamination levels that voided the radiological work permit limit.”
In an April 12 report, the inspectors noted that strontium was detected on one worker’s clothes. The contamination had spread inside one of the rooms in the building but no “significant airborne contamination” was detected, according to that report.
Through April, workers designed and tested a new “shroud” device to contain contamination during the drilling, according to an Energy Department statement.