Kenneth Fletcher
WC Monitor
9/19/2014
A second transuranic waste drum in the Waste Isolation Pilot Plant underground contains a “unique combination” of materials, including a discarded glove, that is believed to have contributed to a reaction and radiation release at WIPP, a Los Alamos National Laboratory official said this week. Only two remediated drums have that combination: the breached drum in WIPP’s Panel 7 thought to be the source of the Feb. 14 radiation release, and another undamaged drum currently stored in WIPP’s Panel 6, LANL WIPP Recovery Leader Terry Wallace said this week at a New Mexico Radioactive and Hazardous Materials Committee meeting. But the two drums are not completely identical in makeup and may vary in pH, officials say.
The breached drum was one of a group of drums remediated at LANL for disposal at WIPP. The Department of Energy has not been able to identify the root cause of the radiation release that has shut down operations at WIPP, though a DOE investigation board is spearheading that effort using analysis from LANL. The suspect drum, which was processed at LANL, includes a mix of organic kitty litter that could act as fuel and sodium nitrate that could be an oxidizer, along with a “unique combination of acids, salts, metals and organics,” according to a copy of Wallace’s presentation. But the reaction would need temperatures as high as 300 Celsius to lead to a reaction, and so far LANL has not been able to pinpoint what may have triggered the event. “We can explain energetic reactions, but not initiation,” the presentation states.
A total of 678 remediated drums have a mixture of nitrate salts, organic absorbent and metal impurities, though that large group has been narrowed down, according to Wallace’s presentation. Out of that group, 16 have absorbed liquid with a low pH, eight of those have absorbed organic liquid neutralizer and two of those contain a discarded glovebox glove. The initial large group is stored at various locations: 508 are in WIPP Panels 6 and 7, while 57 are still at LANL and 113 drums had been moved to the Waste Control Specialists’ facility in Texas for temporary storage before LANL drums were suspected of contributing to the release.
DOE: Second Drum Not a ‘Sibling’
However, the second drum in Panel 6 is not a “sibling” drum to the breached drum, according to a DOE statement. “We are still investigating the cause of the reaction in Panel 7 and evaluating the potential risks posed by other drums,” DOE said in a statement. “DOE continues to focus on implementing the Nitrate Salt Bearing Waste Isolation Plan to avoid potential risks of any drums from the waste stream currently under investigation. Safety of the WIPP workforce is our highest priority and all safety measures are being taken to protect them.”
DOE-LANL Implementing Isolation Plan
The isolation plan was developed in response to an Administrative Order by the New Mexico Environment Department, which required the expedited closure of WIPP Panels 6 and 7 in order to isolate the suspect drums. For the waste at WCS, officials are “pursuing alternatives for processing and disposition,” according to Wallace’s presentation. The 57 drums at LANL will undergo additional processing at the Lab’s Waste Characterization, Reduction and Repackaging Facility. There are several options for those drums, which all involve adding zeolite, a mineral that absorbs the contaminants, and grouting the material in place to prevent any potential reactions. The drums would need to be repackaged to make room for the cement grout, which would ultimately result in a higher number of total drums.
As investigations continue, NMED has made clear that the root cause of the event must be identified before operations can resume at WIPP. While officials have not painted a clear picture of how the reaction occurred, Wallace noted in the presentation that “LANL did not consider the chemical reactions that unique combinations of radionuclides, acids, salts, metals, liquids and organics might create.”
