Progress on WIPP ventilation upgrade

01 February 2022

Work on the Safety Significant Confinement Ventilation System (SSCVS) at the US Department of Energy's Waste Isolation Pilot Plant (WIPP) in New Mexico made significant progress last year following earlier delays caused by the COVID-19 pandemic.

Tag lines are used by riggers to carefully guide an 18,000-pound, 14-foot-diameter section of metal ductwork as it is lifted into a trench at the new utility shaft (Image: WIPP)

Construction of the three major facilities of what will be the largest containment fan system in the underground complex "showed major advancements" in 2021, WIPP said.

The foundation for the New Filter Building, where 1000-horsepower fans will pull air through high-efficiency particulate absorbing (HEPA) filtration, was completed three weeks early, kick-starting construction of the building's walls.

The precast concrete walls and roof of the Salt Reduction Building were also installed. This, WIPP said, was a DOE/HQ Environmental Management complex-wide priority for 2021.

In addition, the utility shaft - the massive air intake for the system - has reached 124 feet (38 metres) of its projected 2275-foot (693-metre) depth. The new shaft saw the installation of a plenum (chamber) and ductwork that will force air into the underground. It will be WIPP's largest shaft at 26 feet (8 metres) in diameter when completed.

The SSCVS system is scheduled to start operating in 2025, providing up to 540,000 cubic feet per minute (cfm) of air in either filtered or unfiltered modes.

"More air allows more machinery to work in the underground and makes for a safer and more comfortable working condition," WIPP said.

Whilst WIPP constructs the SSCVS system, it has prepared to restart one of its legacy fans, the 700-C, in order to maintain ventilation capacity. The WIPP ventilation system currently pulls 170,000 cfm of filtered air throughout the underground. The 700-C fan will provide 240,000 cfm of unfiltered air for non-emplacement activities, such as mining and rock bolting.

Mining of the eighth panel at WIPP was completed in October 2021, seven years after work began. After outfitting with power, communications and air monitors, Panel 8 will be ready to start accepting transuranic (TRU) waste when Panel 7 reaches full capacity in April this year.

WIPP is the USA's only repository for the disposal of TRU waste. Sealed drums of waste - clothing, tools, rags, residues, debris, soil and other items contaminated with small amounts of plutonium and other man-made radioactive elements from the US military programme - are placed in "rooms" carved out of salt rock by laser-guided continuous miner machines.

The WIPP repository is mined out of an ancient salt formation more than 2000 feet below ground. The repository is configured to have eight panels - four on each side of the main access passageways, or drifts - although two further panels are also planned.

Researched and written by World Nuclear News