Open-air demolition using heavy equipment of the Plutonium Finishing Plant (PFP) at the Hanford Site in Washington state resumed on Thursday. It is the first demolition at the plant since an airborne spread of radioactive contamination was discovered in December 2017.
Workers with cleanup contractor CH2M Hill Plateau Remediation Co. were ready to restart teardown on Tuesday, but windy weather delayed the work by two days.
In September, CH2M restarted some lower-hazard work, loading out the demolition debris from the main section of the plant that had remained on the ground since December 2017. The contractor last week completed load out of about 2,500 tons of rubble and debris for disposal at the Environmental Restoration Disposal Facility in central Hanford.
The safety measures successfully instituted for the load out will remain for demolition, said Mark Hughey, CH2M’s deputy vice president for the Plutonium Finishing Plant closure project.
The contamination and high contamination zones around work areas – where precautions, such as protective gear, are required – have been expanded. Fixative is applied to demolition debris at the end of each work day and controls are in place to limit the amount of debris that can accumulate before it is loaded out. Monitoring has been increased, both for airborne radioactive particles and for possible surface contamination. Worker engagement at PFP and communication with Hanford workers on neighboring projects also has been improved, according to Tom Teynor, Department of Energy project director for PFP demolition.
“There can be no repeats of releases of contamination outside posted radiological boundaries,” Teynor said.
During two separate incidents in 2017, 42 Hanford workers inhaled or ingested small amounts of radioactive material at PFP. Particles of contamination were found outside radiological boundaries, including on employees’ cars and across a road used by site personnel that passes PFP. The Washington state Department of Health found plutonium or americium in very small amounts in bulk air samples miles from PFP.
During the Cold War, plutonium came into the plant in a liquid solution and was turned into solid forms that could be used for production of nuclear weapons.
Demolition is resuming initially on the least contaminated areas of PFP, including a remaining vault that was used to store plutonium. The lower risk demolition could be completed in early July, with demolition on more highly contaminated parts of the plant to follow. It will include the more contaminated section that once housed the two main processing lines where employees processed plutonium in lines of glove boxes.
“We’re satisfied that they have procedures in place to allow the lower-risk demolition to proceed,” said Stephanie Schleif, project manager for the plant for the Washington state Department of Ecology. But Ecology and the U.S. Environmental Protection Agency, both Hanford regulators, have not terminated a stop work order on higher-risk work at more contaminated areas of the plant that resulted from the December 2017 spread of contamination.
“We will continue to work with the Department of Energy in reviewing plans and work packages for resuming the high-risk portion of work left at PFP before we lift our stop-work (along) with the EPA,” Schleif said. “Like everyone who follows the Hanford cleanup, we’re eager to see this work proceed safely and be completed.”
CH2M will evaluate whether it is ready to move on to demolition of high-risk areas based on an independent management assessment, with Energy Department approval then required. Although demolition of high-risk areas is not expected to begin until mid-July, the management assessment will be conducted in late April to allow time for any recommendations to be closed out.
After demolition of high-risk areas is completed, a second high-risk project is planned – load out of the rubble from the highly contaminated Plutonium Reclamation Facility, an annex to the main area of the plant. The contamination spread that halted most work at the plant more than 15 months ago was discovered after demolition was nearly completed on the Plutonium Reclamation Facility.
A tentative schedule from last summer had the restart of demolition planned for October 2018 and completion of higher-risk demolition and loadout at the end of May 2019. However, resumption of lower-risk demolition was delayed by the need to train new workers due to staff turnover as better-paying jobs became available at the Hanford radioactive waste tank farms. Work was again delayed by record-breaking cold and snow in February and March at Hanford.
The current schedule projects completion of the work in late September. Under the Tri-Party Agreement that governs cleanup a Hanford, the plant was to be down to slab on grade by the end of fiscal 2017, but with that milestone not achievable the focus has been on completing the work safely. “The contractor is committed, from (President) Ty Blackford down to the work in the field, to proceed at a safe, deliberate speed,” Teynor said.
