SANTA FE, N.M. — Before there was a cat litter problem in the packaging of waste at Los Alamos National Laboratory, there were nitrates.
The public focus on why a LANL waste drum popped open, causing a radioactive leak that shut down the nation’s nuclear waste repository near Carlsbad in February, has been on organic cat litter that shouldn’t have been combined with oxidizing nitrates. That apparently created a combustible mix that somehow ignited and breached the drum.
But it turns out a red flag should have been raised about any processing of waste containing nitrates, even without organic materials added in, before waste drums were shipped from Los Alamos for storage at the Waste Isolation Pilot Plant.
About two years ago, a procedural change was made at Los Alamos, without the standard safety review, removing requirements to stop waste processing and inform management if “Class 1 oxidizers” like nitrates were encountered in the waste stream.
LANL self-reported the issue and it was disclosed last month in a brief public report by the Defense Nuclear Facilities Safety Board.
The Dec. 19 report says that personnel at LANL’s Waste Characterization, Reduction and Repackaging Facility recently indicated that “a procedural change” in waste processing was made without an adequate review called an “unresolved safety question determination.” “The procedural change,” says the safety board report, “was made over two years ago and removed the requirements to stop waste processing and inform management if, among other things, Class 1 oxidizers (such as nitrates), flammable metals or pyrophoric materials were encountered.”
The report goes on to add that the basis-for-operations plan for the Los Alamos waste facility “does not allow processing of these types of materials.”
Investigators believe the radiation leak at WIPP resulted when organic, wheat-based cat litter provided fuel for a chemical reaction with oxidizing nitrate salts that were part of the waste stream packaged at Los Alamos. The nitrates were left over from a process used to extract plutonium.
But the new disclosure is the first suggestion that oxidizing nitrates – even without the addition of organic material – should have been a cause for concern as waste was packaged for WIPP.
The organic litter, serving to absorb liquid in the waste drums, came into use in 2012 and replaced clay-based litter that had been used previously.
So far, how enough heat was generated to start the chemical reaction that breached the WIPP drum reportedly has not been determined. A Department of Energy report on the leak at WIPP, which remains closed and faces a remediation bill estimated at a half-billion dollars, is expected in the near future.
The lab and DOE had no comment on the safety board’s report Thursday. But lab officials have said previously that LANL has self-identified all outstanding issues in its review of the drum leak and has been putting corrective actions into place.
Lab ‘violating own rules’
The safety board’s disclosure of the change in procedures about not processing nitrates without notice provided fodder for more criticism of LANL and its private operator, Los Alamos National Security LCC.
“Adding the organic kitty litter was just the kind of problem that this rule was set up to avoid,” said lab watchdog Greg Mello of the Los Alamos Study Group.
He added in an emailed comment: “Now we are told that LANS violated its own safety regulations even prior to mixing incompatible chemicals by the ton into this waste.
“Strong oxidizers, flammable metals, and pyrophoric materials” – which can combust when they come into contact with air or water – “were not supposed to be processed without further safety analyses. This apparently never happened. A documented safety analysis sets up a safe ‘operating envelope’ for DOE nuclear facilities. LANS proposed this envelope and DOE approved it. Why was it ignored?”
“There is a simple procedure for changing these limits, but LANS didn’t follow it and DOE didn’t make them,” Mello added. “If LANS and DOE had followed their own procedures, the special characteristics of this waste stream would have received extra attention, which we can all agree was needed.”
Nothing in the safety board’s report indicates whether the procedural change on what to do about nitrates and other materials came before waste handlers changed from clay-based to organic cat litter.
State government has fined LANL and WIPP $54 million over the leak. Also, DOE slashed the 2014 management fee for LANS, a consortium including the Bechtel corporation and the University of California, by about 90 percent to about $6 million from around $59 million the previous two years.