Nuclear waste managers at the Waste Isolation Pilot Plant repository near Carlsbad said Oct. 21 that the last nuclear waste was disposed of in an area of the facility marred by years of incidents, including a radiological release that led to a three-year shutdown of the facility’s main operations.

Panel 7 in the WIPP underground was reported full Friday by the U.S. Department of Energy which will now shift emplacement operations to the eighth and final permitted disposal panel at the site.

That panel was officially certified by the New Mexico Environment Department (NMED) in August and expected to begin receiving waste in the coming weeks.

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At WIPP, transuranic nuclear waste made up of clothing materials, equipment and other debris irradiated during nuclear activities like research and weapons development at national laboratories and other facilities operated by the DOE.

It is trucked to the WIPP, located about 30 miles east of Carlsbad and disposed of via burial in a salt deposit about 2,000 feet underground.

As mined panels are filled, the salt is allowed to gradually collapse and permanently entomb the waste.  

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Sean Dunagan, president of Nuclear Waste Partnership – the DOE-hired contractor overseeing daily work at WIPP – said filling and closing Panel 7 will mean underground workers will no longer have to wear respirators and other protective equipment to shield them from radioactive contamination.

That contamination is because in 2014, a mispackaged drum of waste from Los Alamos National Laboratory ruptured and released contamination in the underground, meaning mining and emplacement activities were halted until 2017.

NMED fined the DOE $73 million for the incident, funds used for safety upgrades at the facility.

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The release also meant Panel 7 was kept open and waste was emplaced there for several additional years beyond the two-to-three-year lifetime panels are designed to be mined and accept waste.

This also meant additional ground control measures were needed to prevent the salt from collapsing in Panel 7 before it was full, and ground leveling was needed as the salt “heaved” over time and made the floor of the panel uneven for equipment.

“Completing emplacement activities in Panel 7 means our team will once again be in an area free of radioactive contamination; they will no longer need to use respirators or special protective clothing,” Dunagan said.

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About 20,000 waste containers were emplaced in Panel 7 since it began accepting waste in 2013, records show.

To make room for all of that waste, about 160,000 tons of salt are excavated for each panel.

Now that it’s full, WIPP officials said Panel 7 would be closed off along with its intake and exhaust drifts using a steel bulkhead, a 100-foot layer of salt and another bulkhead.

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Reinhard Knerr, manager of the DOE’s Office of Environment Management (EM) Carlsbad Field Office, which oversees the WIPP project, said the facility’s ability to continue accepting waste was needed to address the environmental impacts of DOE’s sites around the U.S.

“Filling Panel 7 allows us to continue our important national mission of disposing of transuranic waste, which ensures people living near sites where TRU waste is currently stored, are safer today because of WIPP’s role in EM’s nuclear waste cleanup strategy,” he said.

But some estimates show TRU waste disposal at WIPP could continue for decades until 2080, well after the projected the two- or three-years Panel 8 was expected to operate.

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A lot of space was abandoned in the WIPP underground due to contamination from the 2014 event, and officials are hoping to add at least two more panels to make up for the loss.

Language to allow that additional disposal space was included in the DOE’s application to renew its 10-year permit under review by the NMED.

And a November 2020 report from the Government Accountability Office said WIPP could require at least nine more panels to fulfill its statutory waste capacity of about 6.2 million cubic feet of waste, a move that would require a modification to WIPP’s permit and approval from NMED.

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That process is ongoing, and it was unclear exactly when the new permit would be issued.

The DOE's initial renewal application notably removed the previously specified 2024 closure date, leaving the timeframe undefined with officials contending WIPP could stay open as long as it took to meet its statutory capacity.

“DOE officials decided that they would construct additional panels up (to) the point at which the volume of TRU waste that could be disposed of in the panels equaled WIPP’s statutory capacity,” the report read.

Adrian Hedden can be reached at 575-628-5516, achedden@currentargus.com or @AdrianHedden on Twitter.