BY GEORGE LOBSENZ
While previously suggesting that the nuclear waste drum that erupted at the Waste Isolation Pilot Plant had “unique chemistry” that may have caused the accident, the Energy Department recently notified New Mexico officials that they are preliminarily reclassifying hundreds of similar waste drums from Los Alamos National Laboratory as potentially containing ignitable or corrosive materials, indicating they may pose previously unrecognized safety issues, IHS The Energy Daily has learned.
Los Alamos formally notified the New Mexico Environment Department (NMED) July 30 that it was “provisionally” classifying 89 nitrate salt-bearing waste drums now stored at the nuclear weapons lab as potentially containing ignitable materials, as defined by the Environmental Protection Agency under code D001 in its regulations on hazardous waste characteristics.
Further, NMED officials disclosed earlier this month that Los Alamos also had verbally informed them that the lab was “conservatively” reclassifying 29 drums containing unremediated nitrate salt-bearing waste as potentially holding corrosive materials, as defined by EPA under code D002 of its hazardous waste regulations.
Officials at the Waste Isolation Pilot Plant (WIPP), DOE’s underground repository in New Mexico for transuranuic waste, also notified NMED that they were reclassifying 368 Los Alamos-generated nitrate salt-bearing waste drums as potentially holding ignitable materials.
Further, Los Alamos said another 119 waste drums now stored at a Texas low-level nuclear waste dump operated by Waste Control Specialists may hold ignitable materials.
The reclassification of the Los Alamos waste drums follows extensive investigations by Los Alamos and other DOE waste experts who have been trying to determine what caused an apparent chemical reaction in one nitrate salt-bearing waste drum stored at WIPP on February 14, causing the first radioactive release from WIPP in its 15 years of operation.
The energetic reaction dislodged the lid of the drum and left scorch marks on it, but DOE says its experts to date have not been able to pinpoint what waste materials in the drum caused the eruption.
Nonetheless, a senior Los Alamos official suggested to state legislators last month that the drum eruption appeared to be a one-off event due to its particular waste contents and chemistry.
In a July 23 presentation to the New Mexico legislature, Nan Sauer, Los Alamos’ associate director for chemistry, life and earth sciences, said the lab was looking at the possibility of a chemical reaction potentially involving kitty litter—which is used to absorb liquids in waste drums—along with neutralizers, acids, nitrate salts and tungsten-lined lead gloves inside the drum. The presentation suggests that the breached drum contained a mixture of materials that others processed at Los Alamos did not, referring to the “unique chemistry” of the drum.
Following the WIPP event, DOE officials reclassified the breached drum as potentially containing ignitable materials but did not extend that reclassification to other nitrate salt-bearing drums from Los Alamos until the formal notification of NMED last month.
In a statement to IHS The Energy Daily Wednesday, Los Alamos said it decided to reclassify some nitrate salt-bearing waste drums as potentially containing ignitable materials to provide an additional measure of safety for certain waste streams that already were being safely stored at the lab and WIPP.
Lab officials made clear that the reclassification was not necessarily permanent and might be changed in the future, depending on continuing investigations into the breached drum by Los Alamos and DOE’s Carlsbad field office, which oversees WIPP.
“In an effort to conservatively manage specific waste streams of concern, the Carlsbad Field Office (CBFO) and Los Alamos National Laboratory (LANL) have determined that certain nitrate salt-bearing waste containers indicate characteristics of potential ignitability,” Los Alamos said in the statement. “As required by federal regulations, CBFO and LANL have applied the U.S. Environmental Protection Agency Hazardous Waste Ignitability Code to this waste stream and notified the state regulators.
“The application of the waste code does not affect the permanent underground disposal of the waste at WIPP,” Los Alamos added. “The [reclassified] drums at Los Alamos are stored safely and securely in robust structures with high efficiency particulate air filtering and fire detection and suppression systems. The drums are visually inspected and monitored for temperature daily.”
NMED officials did not respond Wednesday to repeated requests for comment on the reclassification of the waste drums or what that might mean for their view of the WIPP drum event.
However, in an August 7 letter to Los Alamos, New Mexico Environment Secretary Ryan Flynn asked Los Alamos officials to provide the analyses and data supporting the “provisional” reclassification of drums as potentially containing ignitable or corrosive wastes.
Los Alamos told NMED in a July 30 letter that it was “provisionally” applying EPA Hazardous Waste Number D001 for the characteristic of ignitability to 89 nitrate salt-bearing waste drums stored at the lab.
“The permittees are re-evaluating the waste characterization information concerning these nitrate salt waste streams,” Los Alamos said in the letter. “Pending completion of this re-evaluation, permittees are conservatively adding the D001 waste number. Because this evaluation is ongoing, the application of D001 is considered provisional and may change to include and/or remove containers/waste streams in the future.”
But Flynn appeared to question Los Alamos’ action, ordering the lab to “thoroughly describe and provide the reasoning and analyses for the speculation that both the remediated and unremediated [nitrate salt-bearing] waste is an oxidizer and the subsequent assignment of EPA Hazardous Waste Number D001.”
Flynn also expressed skepticism that Los Alamos could “provisionally” reclassify wastes as ignitable under current federal hazardous waste regulations and guidance.
“The permittees shall describe the regulatory basis for ‘provisionally’ applying the EPA Hazardous Waste Number D001,” Flynn said. “The state is not aware that this approach is supported by regulations or EPA guidance documents. If there are such provisions, the permittees shall provide copies of or links to the documents.”
Flynn further asked Los Alamos to provide documentation supporting its verbal notification to NMED that it was “conservatively” assigning EPA Hazardous Waste Number D002 for potentially corrosive wastes to some of the 29 unremediated nitrate salt-bearing waste drums at the lab.
“The permittees shall thoroughly describe and provide the reasoning and analyses, including the associated documentation for each container (e.g., real-time radiography videos and batch data reports, visual examinations batch data reports, etc.) why the unremediated waste is corrosive and why the assignment of EPA Hazardous Waste Number D002 is appropriate,” he said.
Flynn also asked Los Alamos to identify the specific waste drums holding potentially corrosive wastes and to describe the lab’s plans for processing wastes to remove concerns about ignitability and corrosivity.
Los Alamos previously characterized the nitrate salt-based wastes on the basis of so-called “acceptable knowledge” about their composition, which generally reflects analyses done on similar waste streams generated by the lab in the past. A Feb. 10, 2014, Los Alamos document summarizing acceptable knowledge about the nitrate salt wastes states flatly that “these salts do not meet the definition of a [Department of Transportation-classified] oxidizer (i.e., they would not stimulate combustion)” and thus were not ignitable wastes.
However, in an August 13 letter to DOE officials at WIPP, two senior Los Alamos officials said that “due to recent events at WIPP, and re-evaluation of acceptable knowledge information [about the nitrate salt-bearing wastes],the Carlsbad Field Office notified LANL that there was a [waste] manifest discrepancy based on WIPP’s determination that nitrate salt-bearing waste containers required application of EPA Hazardous Waste Number D001 and Department of Transportation subsidiary Hazard Division 5.1.”