Workers at the US Department of Energy (DOE) Office of Environmental Management (EM) Portsmouth Site have reached another milestone by completing construction of the fourth cell at the On-Site Waste Disposal Facility (OSWDF).
The Portsmouth Gaseous Diffusion Plant operated from 1954 to 2001. Located in Pike County, Ohio, the plant occupies about 1,200 acres of the 3,777-acre federally-owned Portsmouth Site. The plant was one of three large gaseous diffusion plants constructed to produce enriched uranium to support the nuclear weapons programme and later enriched uranium used by commercial nuclear reactors. After the Cold War, weapons-grade uranium enrichment was suspended, and production facilities were leased to the private sector. In 2001, enrichment operations were discontinued at the site.
EM began environmental clean-up at the site in 1989 and work continues in cooperation with the US and Ohio Environmental Protection Agencies. Decontamination and decommissioning of the plant began in 2011.
In 2021, the safe, controlled structural demolition of the large X-326 uranium-enrichment Process Building began and was completed a year later. Teardown of the 56-acre facility was completed three months ahead of schedule. At the same time, environmentally impacted soils were excavated placed in the OSWDF – a specially engineered disposal site. Each cell has a multi-layer liner and cap system to consolidate demolition debris into one centralised, confined space that protects public health and the environment. All water runoff from the demolition project and the OSWDF is being detained and treated in specially designed facilities.
Teardown of the two-storey 33-acre X-333 Process Building is underway – the second of three former uranium enrichment process buildings to be demolished at the site.
“Completion of the fourth OSWDF cell is essential to completing the next phase of the cleanup mission at the Portsmouth Site,” Federal Project Director Jud Lilly said. “The fourth cell is needed for disposal of debris from the demolition of the next process building.” Placement of debris from X-333 into the new cell is slated to begin this spring.
Two more cells of the disposal facility are scheduled for completion later this year. When complete, OSWDF will comprise 10 cells with the potential for two additional contingency cells to accept demolition debris and impacted soils from the deactivation and demolition project that meet the waste acceptance criteria.
In April last year, EM crews finished excavating an approximately seven-acre space for the fourth cell. Next, they placed select fill, a clay liner and geosynthetic material to finish the cell. “We are proud of the quality construction of the cell while maintaining a safe work environment,” said Paul Larsen, director of OSWDF at Fluor-BWXT-Portsmouth, EM’s decontamination and decommissioning contractor for the site.
