The Waste Isolation Pilot Plant in southeastern New Mexico is once again accepting shipments and processing transuranic waste following a two-month annual maintenance outage. According to the Department of Energy, WIPP is back to accepting five waste shipments per week, with post-pandemic plans to increase shipments to 10 per week.
The maintenance outage lasted from February 15 to April 15, with 97 work activities using personnel from six departments, including mine operations, waste handling, hoisting, work control, safety, and engineering. The break included site-wide power outages to accommodate electrical work.
WIPP is the nation’s only deep geologic repository for nuclear waste. Through the end of March, WIPP has accepted 12,845 shipments of waste from DOE generator sites throughout the country, and WIPP drivers have safely driven 15.3 million loaded miles, the DOE said.
The work: Outage projects included inspections, maintenance, and repairs to systems in waste-handling buildings, including four processing docks and four overhead cranes in the contact-handled waste bay. This allowed waste handlers to process eight TRUPACT-II waste casks on April 5, the equivalent of 112 55-gallon drums of waste. The waste is emplaced in WIPP’s underground repository, 2,150 feet beneath the surface.
“The amount of equipment repairs performed during the outage resulted in a huge improvement for waste handling,” said WIPP waste handling manager Mars Dukes. “To have all of our equipment operating properly allows us to safely meet the demands of the accelerated shipping schedule and positions our team for success.”
In the largest project in this year’s outage, crews removed 170 feet of railroad-like rails used to transfer waste pallets at the bottom of the waste hoist. The project addressed a problem where movement of salt rock had heaved the floor so that the rails were no longer level. The rails and metal plates were removed, a mining machine dug five feet down into the salt floor, and the floor was leveled. Gravel ballast and run-of-mine salt were added as a base layer, and the rails and metal plates were reinstalled.
Preventive maintenance at WIPP is done on a schedule that can range from daily to annually. Quarterly efforts generally take about a week to tackle. Once a year, a multi-week outage is scheduled to handle projects needing the greatest effort that cannot be performed while normal transuranic waste operations are ongoing.
The 700-C fan: Also, during an April 15 virtual town hall meeting, the DOE’s Carlsbad Field Office and Nuclear Waste Partnership (NWP) shared environmental monitoring data from a four-hour test of a WIPP ventilation fan held in January. To increase airflow to the underground, the DOE and NWP, the management and operations contractor for WIPP, plan to restart the repository’s 700-C fan, one of WIPP’s legacy unfiltered exhaust fans.
According to the DOE, sampling data conducted during the test confirmed that routine operation of the 700-C fan would result in annual exposures 5,000 times less than the Environmental Protection Agency’s threshold limit of 10 millirem per year. Prior to the test, 700-C was examined to ensure any radiological emissions caused by running the fan would be well below regulatory standards.
The 700-C fan has a capacity of up to 240,000 cubic feet per minute of air to the underground. The increased ventilation will improve the overall air quality in the repository by more efficiently exhausting emissions from diesel equipment used during mining and ground control activities. Because 700-C exhausts directly to the environment, the fan will not be run while waste is being emplaced underground.
Electric vehicles: The DOE is also investigating the use of low-emission and battery-electric vehicles in the underground to address worker-safety issues associated with diesel emissions, meet regulatory requirements, and increase efficiency of operations.
WIPP operates 80 vehicles in its underground fleet, with 37 of those identified as integral to operations, according to the DOE. WIPP staff estimates it will take five years to replace or convert all 37. Battery-powered equipment can range from small forklifts to larger haul vehicles.
The site can handle the increased power demands but will need to create mined-out alcoves and install recharging stations, according to the DOE.