While the Department of Energy’s Carlsbad, N.M., field office believes passage of time has made transuranic drums stranded since 2014 at Waste Control Specialists in Texas safe for travel to the Waste Isolation Pilot Plant, the Defense Nuclear Facilities Safety Board is not yet convinced.
That is the crux of a Sept. 8 letter sent to Secretary of Energy Jennifer Granholm from the Defense Nuclear Facilities Safety Board (DNFSB) and posted on the panel’s website.
The remaining 100-plus drums from Los Alamos National Laboratory, stored at the commercial disposal site in West Texas, contain mixtures of nitric acid or nitrate salts with polysaccharides: the same type of waste involved in the 2014 accident where a drum overheated and ruptured in the Waste Isolation Pilot Plant (WIPP) underground, resulting in a radiological release that shut WIPP for three years.
The 2014 WIPP radiological release event resulted from a chemical reaction between organic kitty litter and nitrate salts in the waste.
In May 2019, DOE’s Carlsbad office “concluded that such waste will not undergo autocatalytic runaway reactions after the waste has been aged for a specified time period,” DNFSB said. But the board said Carlsbad “lacks the technical basis to support that conclusion.”
This type of waste “may not be acceptable for disposition at WIPP unless additional technical justification is provided, controls are implemented, or the waste is treated,” DNFSB said.
“DOE continues to evaluate several approaches to safely and compliantly disposition the waste and will take into account the DNFSB’s concerns,” before responding to the board, a DOE spokesperson said by email Tuesday.
Carlsbad’s assessment, informed by from Los Alamos and other DOE research, found that difficult waste can be safe to ship “after aging beyond the latency periods” of anywhere from 200 days to 730 days, depending on the exact mixture of the transuranic waste, according to the DNFSB material.
The DNFSB requested that DOE “provide a report and briefing” by Dec. 7 that “describes its plan for safely managing these waste materials across the complex,” DNFSB Chair Joyce Connery said in the letter.
Note: Second paragraph modified Oct. 4 to change reference to Sept. 8 letter.
