Kenneth Fletcher
WC Monitor
3/13/2015
With 57 drums currently at Los Alamos National Laboratory containing similar materials to a drum that caused a major radiological release, officials plan to repackage the drums within the next two years using a “cold and dry” process. A drum processed at Los Alamos containing a volatile mixture of nitrate salts, organics, acids and metals has been found to be the source of the February 2014 radiological release at the Waste Isolation Pilot Plant. Investigations are currently being wrapped up into the root cause of the release (see related story). Meanwhile, hundreds of drums with similar contents are emplaced underground at WIPP, as well as being stored in controlled and closely monitored environments at LANL and the Waste Control Specialists facility in Texas. At Los Alamos, officials said last week they hope to repackage the waste safely by the time a new cleanup contractor is in place within the next two years.
The release at WIPP is thought to have occurred in part to the mixture of nitrate salts, organic absorbent and other compounds in a waste drum, which could react violently when exposed to high temperatures. Los Alamos is looking at using temperature as a control for repackaging the drums. “One of the things we are looking at with the salts is the option to cool them, and that allows us to then process them with the adequate safety margin,” Department of Energy Los Alamos Waste Disposition Supervisor David Nickless said last week at an industry day for the Los Alamos cleanup procurement. He added: “Right now what looks like the most promising is what I’ll call cold and dry. So what I mean by that is we’ll cool the waste to make it safe to handle and then we would add most likely a zeolite, which is an inorganic mineral, to essentially deactivate the hazardous waste.”
That process could likely take place at LANL’s Waste Characterization Reduction and Repackaging Facility, though an additional capability would be necessary to cool the waste. “We still have a lot of work to do,” Nickless told WC Monitor last week, emphasizing that no final decisions have been made. “But it looks like the leading candidate for moving forward is to use a temperature control to safely handle the waste and then looking at adding an inerting agent such as zeolite to the waste.”
Hundreds of Drums With Mixture Remain
A total of 678 remediated drums have a mixture of nitrate salts, organic absorbent and metal impurities, according to a Los Alamos presentation from September. The initial large group is stored at various locations: 508 are in WIPP Panels 6 and 7, while 57 remediated drums 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. However, only one other drum is believed to be very close in composition to the one linked to the WIPP release—16 drums have absorbed liquid with a low pH, eight of those have absorbed organic liquid neutralizer and two of those contain a discarded glovebox glove, according to the presentation.
WCS Drums Pose a Challenge
For the volatile waste at WIPP, New Mexico has called on the facility to close open waste panels in the underground as soon as possible, in part to prevent any potential additional releases. But the drums at WCS pose a particular challenge because no container has been certified to ship the potentially ignitable waste for processing at Los Alamos and they can also not be accepted at WIPP. “You have two options at this point,” Nickless said. “One is to establish a capability at WCS to treat it. The other option would be to look at what regulatory hurdles you’d have to overcome to dispose of it in one of their facilities in the federal cell.” Plans are all “very preliminary” at this point, he said, stating that once a process is proven at Los Alamos then the WCS drums can be addressed.
DOE Responds to NMED Request
This week DOE responded to a New Mexico Environment Department request, providing dozens of documents regarding the nitrate salt wastes at Los Alamos stretching back more than a decade. Notably, the documents, available here and here, reduced the total number of nitrate salt bearing containers at Los Alamos from 707 to 610. That is because many of the containers had been cemented, removing them from the list of potentially volatile containers. The 57 containers slated for repackaging are the ones that have been remediated with organic absorbent.
