Risks linger with Plutonium Finishing Plant’s demolition
By Arielle Dreher
The Plutonium Finishing Plant used to be called the Z Plant when the Hanford nuclear site produced plutonium because it was the end of production of the radioactive material before it was shipped to weapons production facilities.
The PFP was a group of 60 buildings, which began operating in 1949, where workers produced “buttons” of solid plutonium, the size of hockey pucks. PFP was the last stop for plutonium on the Hanford site before it was built into nuclear weapons elsewhere in the country.
Today, the demolition of the Z Plant poses one of the greatest challenges to U.S. Department of Energy workers and contractors tasked with demolishing it without exposing themselves, the environment or others to the radioactive remnants unearthed.
During summer 2017, bioassay results found 31 workers had ingested, inhaled or absorbed radioactive contamination after a spread was detected due to work around PFP. Demolition continued, however, until December 2017, when workers noticed their air samplers detected elevated radiation levels.
CH2M Hill Plateau Remediation Co., the contractor responsible for demolishing the PFP, called a stop-work at that time to conduct surveys and samples. These surveys snowballed into the revelation that contamination had spread from PFP demolition zones to not only workers directly engaged in the work but to areas outside of the demolition zones. Areas outside of mobile administrative offices as well as vehicles — both personal and government — had traces of low-level radiation.
More than 300 workers requested bioassays following the December contamination spread, and 11 of them were found to have ingested, inhaled or absorbed some radioactive contamination. In total, in 2017, 42 Hanford site workers had internal contamination as a result of working on or near demolition of PFP. CH2M Hill maintained its stop-work order, which lasted eight months. It brought in an outside assessment group to review its controls program, and eventually, in summer 2018, the U.S. Department of Energy launched an independent concurrent assessment as well.
The Department of Energy’s review raised several concerns about CH2M Hill’s practices, including a lack of quality on work permitting and radiological controls.
“Information needed for proper completion of the tasks was not always provided, including taking appropriate background measurements, evaluation of potential radon interference, proper techniques for collecting transferability samples, and methods for ensuring sample integrity,” according to a 2018 Department of Energy memo.
The Department of Energy did note that CH2M Hill improved its practices as its assessment continued, however, and said that improvements to both the control and survey programs were made. Department of Energy planned to continue to conduct independent assessments, as it deemed necessary when work was set to begin. CH2M Hill was cleared for low-level risk demolition work on PFP in fall 2018.
“We really engaged the workforce to come up with a revised strategy for getting back to work and came up with a phased approach, starting with the lower-risk demolition work, and that work resumed last September 2018,” said Dieter Bohrmann, communications specialist at CH2M Hill.
“Under these number of enhanced controls for workers’ safety, increased boundaries, additional monitoring, better communication with the workforce and neighboring projects—so a whole slate of enhanced measures that would allow the project to proceed safely and deliberately—we got back to work.”
The largest part of lower-risk work on demolition is removing securely covered or stabilized debris left on the ground after demolition happens, Bohrmann said, and for most of the time since work has resumed at the PFP plant, crews have been removing debris. Recently, they started demolition again, this time on a vault.
“This is a big risk-reduction effort at the Hanford site, and one of the highest priorities in the central part of the Hanford site,” Bohrmann said.
Figuring out how to safely remove all of the plutonium from the PFP took about 20 years to complete, said Mark Heeter, public affairs specialist with the Department of Energy’s Richland Operations Office, pointing out that actual demolition of buildings began in November 2016. PFP has always been a high priority on the Department of Energy’s list, Heeter said.
“For many years, it was a very high priority because it was one of the most hazardous facilities in that complex,” he said. “… In fact if you looked all across the country, it was a big target for what we were looking close to finishing up.”
Before CH2M Hill can begin to demolish anything deemed high-risk work again, the independent management assessment must be finished to determine whether it can proceed. That assessment began at the end of April. If approved, CH2M Hill might be able to meet current scheduled deadlines to complete demolition by the end of September 2019.
The original milestone attached to demolition of PFP was set for 2017, but after the contamination spreads, that deadline was adjusted accordingly. The goal, Bohrmann said, is to be slab-on-grade with the main processing plant knocked down and debris removed by the deadline. However, work at PFP is not so much deadline-driven as it is safety-driven.
“One of the effects of (the December 2017 contamination event) is that we recognized and reaffirmed the fact that we have to do this at a safe and deliberate pace,” Heeter said. “The safe and deliberate pace to ensure that we can do everything we can to prevent the spreads of contamination … is critical.”
Higher-risk work to complete demolition of the plant includes pulling out pipelines underneath the processing facility, as well as removing a pile of rubble with the remains of parts of the PFP. For now, CH2M Hill representatives are optimistic the work can be finished in this fiscal year, which ends in September. Heeter said the management assessment represents closing the feedback loop for workers, as well as regulators and labor unions as work processes are decided going forward.
“We continue to take in information and use that to guide or help guide our decisions on the work that remains,” Heeter said.
Bohrmann believes the progress made so far on debris removal on PFP since last fall speaks to renewed collaborations amongst all parties involved in the work.
“It’s been a group effort,” he said.