The Environmental Protection Agency has asked the Department of Energy to prepare a corrective action report by the third week of April after the spread of radioactive contamination was discovered at the Hanford Site following a November windstorm.
Some contamination from the 618-10 Burial Ground was found across Route 4, a public road between the city of Richland and the secure Wye Barricade where drivers must show a security badge to enter the Hanford Site. Further contamination was discovered in follow-up surveys and is believed to be legacy waste spread by plants and animals before the windstorm.
DOE and state officials have said the spread of waste did not endanger the public or workers. The amount of contamination, found on multiple specks or sand-like grains, was small, and radioactivity levels were low. However, the Washington State Department of Health is concerned that control of contamination was lost and wants to make sure issues are corrected to prevent a more serious spread of contamination, said John Martell, of the department’s Office of Radiation Protection.
On Nov. 16, work was done with concreted drums excavated from the 618-10 Burial Ground trenches about 6 miles north of Richland. Before disposal at the burial ground from 1953 to 1964, the drums had been filled with concrete and then a pipe was inserted in the center to hold some of the more radioactive waste from research in the 300 Area. After the drums are dug up, heavy equipment is used to place them in large boxes filled with a liquid grout mixture at the burial ground.
The drums are smashed up within the mixture by heavy equipment. Care must be taken to keep the grout from drying during mixing and sampling. If it dries, it poses a challenge to controlling contamination spread. Once mixed the material is loaded into boxes to be trucked to the Environmental Restoration Disposal Facility [ERDF] in central Hanford for disposal.
After work was finished on Nov. 16 routine checks found some specks of contamination had spread, and fixative was applied to soil in the area, said Bryan Foley, DOE deputy project manager for the river corridor. The next day workers applied fixative in anticipation of the forecast of windy weather. Wind speeds were unusually high, reaching 70 to 75 mph over the burial ground. When surveying was done after the storm, bits of contamination were found to have spread toward the highway.
Two contaminated grains were found across the highway, said Stacy Charboneau, manager of the DOE’s Richland Operations Office. A street sweeper was brought in to clean that section of the highway. Sweepings were checked for radioactive contamination and none was found. Surveys of the highway, heavily used by commuting workers, also turned up no contamination on the road.
EPA said that during a briefing Nov. 24 it received information indicating that all radiological material was collected at the 618-10 Burial Ground. However, the federal agency said on Dec. 11 the state Department of Health conducted a post-corrective action survey for EPA and found additional radiological material outside of the area posted for radiological control. DOE determined that the Department of Health had found specks of legacy contamination from the urine of animals that had been contaminated or bits of contaminated dried tumbleweeds. The weeds have deep roots that can infiltrate contaminated areas.
Washington Closure previously has had issues with contamination spread from the 618-10 Burial Ground. Plastic used to wrap contaminated material would become brittle and small pieces of contaminated plastic would spread, including to beyond the burial ground’s boundary fence, according to one incident described in a weekly staff report of the Defense Nuclear Facilities Safety Board. It reported contamination spread as early as summer 2014.
The November 2015 incident occurred because of the failure to implement additional measures for controlling small debris, according to EPA. It also said the radioactive material in the concreted drums is difficult to control and that insufficient water may have been used when the drums were being processed. Water is sprayed near the boxes where work is done to prevent the spread of contamination.
Some changes have been made to procedures since November including putting plastic bags around grout and waste mixtures as they are sampled to see if they meet ERDF acceptance criteria, Foley said. Contamination control has been improved for the excavation implements used to smash the drums within the grout, and fixative coverage has been improved. The improvements made “are not so much new controls, but better implementation of existing controls,” Foley said. The spread of legacy waste “is a matter that is alarming to EPA and requires further investigation and discussion,” EPA said in its letter to DOE.
The report requested from DOE is to include a chronological timeline and summary of all loss of control events at the 618-10 Burial Ground, the corrective actions for each event, and the revised practices and technologies to be used to prevent future loss-of-control incidents.
