The possibility of storing excess plutonium at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, N.M., coupled with increased oil and gas drilling in the area, mean the Energy Department needs to re-evaluate the safety of the world’s only open transuranic waste storage facility, according to Stanford University researchers.
Those factors, along with a pair of high-profile safety failures in 2014 at the facility, “really illustrate the challenge of predicting the behavior of the repository over 10,000 years,” Rod Ewing, a professor in the California university’s Department of Geological and Environmental Sciences, said in a press release calling on DOE to perform a new documented safety analysis at WIPP.
The Stanford release hit the wire the same day Ewing and two co-authors published a longer commentary on WIPP safety in the journal Nature. The Nature piece is titled “Policy: Reassess New Mexico’s nuclear-waste repository.”
The Waste Isolation Pilot Project opened in 1999 and was designed to safely store, for 10,000 years, laboratory equipment and other items contaminated by production of weapon-grade nuclear material at various DOE sites. WIPP is located about half a mile underground in a 250-million-year-old salt deposit some 300 miles southeast of Albuquerque. The facility mainly stores equipment contaminated by plutonium-239, plutonium-240, americium, and curium.
After the Obama administration in 2010 sealed a new nuclear arms reduction pact with Russia and cut off funding for the proposed Yucca Mountain nuclear waste repository in Nevada, WIPP faced the prospect of storing 34 metric tons of tons of diluted weapon-usable plutonium it was not designed to accommodate, Ewing said. The material is to be processed under a 2000 agreement with Russia, which pledged to eliminate an equal amount of plutonium.
DOE’s plan of record for this material, which an agency spokesperson in Washington noted this week, is to convert all 34 metric tons of into mixed oxide fuel (MOX) suitable for commercial reactors. The conversion would take place at the MOX Fuel Fabrication Facility now under construction at the agency’s Savannah River Site in Aiken, S.C.
However, the Obama administration has gradually distanced itself from MOX refining, citing the great expense of building the MOX Fuel Fabrication Facility. The final August 2015 report of the DOE’s Plutonium Disposition Red Team, chaired by Oak Ridge National Laboratory Director Thom Mason, found diluting the 34 tons of material below weapons grade for storage at WIPP is the most affordable disposal option, given DOE’s current top line.
Lawmakers in Congress have repeatedly stood up for the MOX Fuel Fabrication Facility. Most recently, Rep. Joe Wilson (R-S.C.) said he was told this week during a tour of the Savannah River Site that mothballing the facility — which a pair of incongruous reports from 2015 pegged as somewhere between 50 percent and 70 percent complete — could cost $500 million or more.
A spokesperson for the National Nuclear Security Administration, which manages refining activities at Savannah River, said by email Thursday that closing the MOX Fuel Fabrication Facility would take three years and cost between $500 million and $750 million. The finding was part of a report titled “Study on the Disposition of Weapons Usable Plutonium,” which lawmakers ordered DOE to prepare as part of the National Defense Authorization Act of 2015.
Even if the MOX facility is built, some weapon-grade plutonium could still end up in WIPP. Besides the 34 metric tons of material to be disposed of under the nuclear de-escalation pact with Russia, the U.S. government has identified 13.1 metric tons of surplus weapon-grade plutonium, now stored at the Savannah River Site, that needs a permanent home. Just over half that material is in pit form, meaning it could easily be plugged into an atomic warhead and become the weapon’s nuclear trigger; just under half the total is in non-pit form.
DOE in December said it would prefer to dilute the roughly 6 kilograms of non-pit material and store it at WIPP. The agency broached the idea in a Dec. 24 update to the Final Surplus Plutonium Disposition Supplemental Environmental Impact Statement it released last spring. That preferred alternative of WIPP disposal will not become final until the agency issues a record of decision saying so — something that would not happen until late January, at the earliest, the agency said in the Dec. 24 document.
If, on the other hand, the MOX Fuel Fabrication Facility is closed — something Congress would have to approve even if the Obama administration moves to defund the project in the fiscal 2017 budget request expected to drop Feb. 9 — the DOE-led Red Team said WIPP’s safety record proved it was capable of accommodating the 34 tons of diluted plutonium.
Ewing took issue with that conclusion, saying the 16-square-mile facility would have to be enlarged to take on the added material and that DOE’s proposal to seal the diluted plutonium in a classified blend of so-called “inert” material was questionable.
“Inert materials are rare,” Ewing wrote in Nature, “particularly those that must remain so for thousands of years.
Ewing also pointed to a pair of 2014 safety lapses at WIPP — an underground fire and an unrelated radiation release — as evidence DOE overestimates the facility’s safety.
The underground storage area has been closed to waste emplacement for nearly two years, but DOE plans to reopen WIPP by Dec. 31. On Thursday, the agency said its Carlsbad Field Office had approved WIPP’s new integrated performance measurement baseline, which details the department’s updated cost and schedule plan for reopening the facility. DOE did not release the document, but said it would share more information at a WIPP town hall slated for April 7 at the Carlsbad City Council Chambers.
Another of Ewing’s concerns with WIPP is the possibility of above-ground contamination because of increased fossil fuel drilling in southern New Mexico. If exploratory boreholes punch through the salt bed encasing WIPP and into brine reservoirs below, salty water could flow into the facility and carry radioactive contaminants to the surface, according to the Nature piece.
In the 1990s, DOE projected miners in the area would drill just about 70 boreholes per 0.4 square miles a year over 10,000 years. However, since WIPP opened, new drilling techniques such as hydraulic fracturing, or fracking, have increased drilling in the Carlsbad region. From 2002 to 2012, for example, Ewing pointed out annual drill rates have been closer to 150 boreholes per 0.4 square miles.
A DOE spokesperson in Washington said periodic reviews mandated by the Environmental Protection Agency factor in changes to the geological environment at WIPP, human-driven or otherwise. “Every five years since WIPP opened in 1999, the U.S. Environmental Protection Agency evaluates changes in geological conditions and practices at WIPP as part of the recertification process,” the spokesperson said. “EPA has continued to determine that the facility meets its performance objectives and all the requirements of EPA’s disposal regulations.”
