Workers continue to be contaminated with small amounts of radioactive material at Hanford’s Plutonium Finishing Plant as they conduct what Department of Energy officials say is the most hazardous cleanup work ever done at Hanford.
Two months ago, DOE sent its contractor, CH2M Hill Plateau Remediation Co., a letter outlining concerns, according to a recently released weekly staff report of the Defense Nuclear Facilities Safety Board.
“Over the past several months (CH2M Hill) has experienced numerous radiological issues at PFP,” the letter said. “Of particular concern are the intake events and the cut/puncture events that can have significant consequences.”
Over the past several months (CH2M Hill) has experienced numerous radiological issues at PFP.
Since then, a worker has had his skin contaminated during work to cut up a glove box, which stands more than 12 feet high and is contaminated with significant amounts of plutonium. The worker was wearing a protective suit that was breached, allowing radioactive material to reach his forehead and hairline.
The suits used for such high-hazard work at the Plutonium Finishing Plant are filled with air and workers are in a congested area. It’s possible that the worker may have brushed against something that caused a small breach in the suit, or the suit could have had a defect.
In addition, three people in a control room watching work on the glove box — where workers once reached their hands through attached gloves into the box to work with radioactive material — had clothing or skin contamination.
An alarm sounded when monitors detected airborne contamination, and the workers immediately left the control room. Two of the workers had contamination on the soles of their boots and the third had contamination on a finger.
Also, since the letter was written, the defense board staff weekly report said that radioactive contamination was spread when a hose from some contaminated equipment being moved was not completely closed off. Workers had no contamination beyond the outside of their protective clothing.
CH2M Hill had issued a “management concern” in August, before DOE sent its letter, according to information from CH2M Hill. The defense board staff report said the company had started an analysis that month to determine actions to better protect workers.
At the time, CH2M Hill was working on three high-hazard jobs that required the use of supplied air respirators, the defense board staff reports noted, and work is continuing on those projects.
Air-filled protective suits used at DOE’s Idaho cleanup suits are being used at the Hanford Plutonium Finishing Plant.
Employees are working to clean up the second of two large and highly contaminated glove boxes; to clean up the Americium Recovery Facility, where an explosion within a glove box in 1976 contaminated the facility and worker Harold McCluskey; and to clean up the Plutonium Reclamation Facility, where plutonium was recovered from scrap material that otherwise would have been wasted.
In July and August, there were incidences of workers’ skin becoming contaminated with radiological material. In some cases, seams failed in the puffy, air-filled protective suits worn by workers. In other cases, contamination spread as the suits were removed after workers left areas contaminated with plutonium that can easily become airborne.
In other cases, the suits may have been damaged during work.
In another incident, CH2M Hill said monitoring showed an intake event, in which a worker had inhaled some airborne contaminated material, in the Plutonium Reclamation Facility. However, the amount was so small that after rounding of numbers, the radiation dose to the worker was considered zero and below the level required to be reported to DOE, CH2M Hill said.
Since August, the contractor has increased management oversight of the work and made changes to how workers take off protective clothing after they exit contaminated areas. It also has improved protective equipment, including adding more padding to make them more difficult to accidentally cut or tear.
CH2M Hill is doing more inspections of the protective suits and has been working with the manufacturer to make sure the suits are robust. CH2M Hill began using the suits at the Plutonium Finishing Plant after seeing the success DOE’s Idaho cleanup site has had with them. CH2M Hill has been working with the Idaho site to learn about their practices with the suit.
Work has been stopped for safety stand downs of the crews assigned to the Americium Recovery Facility and the high hazard glove boxes. A joint brainstorming session between the crews also has been held.
More steps are expected to be taken based on the analysis started in August.
7 of 40,000 incidents per entries into highly contaminated areas
About seven incidents of skin or clothing contamination have occurred since summer during about 40,000 entries into spaces contaminated with plutonium. That’s a low incident rate, according to CH2M Hill, and the incidents should have no health consequences for the workers.
The Hanford Advisory Board has been pleased with the amount of work completed and how it has been conducted. It sent a letter in September praising workers, saying the project exemplifies “the very best of professional and technically initiated cleanup activities.”
By the end of December, CH2M Hill expects work to be completed on the high-hazard glove boxes. The most hazardous work at the Plutonium Reclamation Facility also should be done then. Workers are scraping up contamination from the floor of its tall, central space, called a canyon, where contaminated equipment and spills fell over more than 30 years.
Work on the Americium Recovery Facility and its McCluskey Room is expected to continue until February or March.