It's Official, Kitty Litter Caused a Drum of Nuclear Waste to Explode  

A drum full of radioactive waste exploded at the Waste Isolation Pilot Plant in New Mexico last February, sparking serious safety concerns about the U.S.'s only longterm nuclear storage site. A yearlong government investigation has officially fingered the long-suspected culprit: kitty litter.

Kitty litter? Yes, inorganic kitty litter is commonly used to pack nuclear waste. But the contractor switched to wheat-based organic kitty litter, which reacted with existing chemicals in the waste. "The nitrate salt residues, organic sorbent (Swheat Scoop® ), and neutralization agent (triethanolamine) known to be present represent a potentially reactive chemical mixture of fuels and oxidizers," concludes the report's summary. All 277 pages of the full report are available here.

The technical investigation doesn't explain why the switch was made, but last year, the Santa Fe New Mexican reported it may have all started with a dumb typo. Read more about it below.

[NPR]

AP Photo/Waste Isolation Pilot Plant

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How a Typo May Have Turned a Drum of Radioactive Waste Into a Bomb

In February, a drum of radioactive waste exploded at U.S.'s only underground nuclear waste repository. The Santa Fe New Mexican has released a bombshell report on the comedy of errors, which seems to have all started with a typo specifying the wrong type of kitty litter. Yup.

The Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico is now shut down, awaiting a $500 million recovery plan that could take years. WIPP is made of up salt caverns, which are supposed to safely entomb barrels of radioactive waste for thousands of years. The barrels contain gloves, equipment, and other waste products contaminated by nuclear weapons research, and they're often packed with kitty litter to absorb extra liquids before being sealed, hopefully for eons.

Waste Drum 68660, the one that burst, was packed at Los Alamos National Laboratory (LANL), the Manhattan Project site that is 300 miles north in New Mexico. According to the New Mexican, the LANL and its contractors made a number of missteps, including using an organic wheat-based kitty litter instead of a clay-base inorganic kitty litter. Thanks to that switcheroo, the drum ultimately contained the ingredients of a bomb. On February, the drum blasted open. Temperatures rose to 1600 F in WIPP's underground cavern, and 20 workers were exposed to low levels of radiation.

Officials tell the New Mexican the exact conditions of the explosion have not been recreated in a lab. But the organic kitty litter has been under suspicion because it can release heat as it decomposes. Waste Drum 68660 also contained nitrate salts, trace metals from a glove, and acid neutralizer to deal with its high acidity, which altogether provided the other components needed for an explosion.

LANL has never explained why it switched to organic kitty litter, though emails obtained by the New Mexican suggest it originated with a dumb typo in a LANL policy manual that had gone unnoticed by higher ups for over a year:

The revision, approved by LANL, took effect Aug. 1, 2012....explicitly directed waste packagers at the lab to "ENSURE an organic absorbent (kitty litter) is added to the waste" when packaging drums of nitrate salt.

"Does it seem strange that the procedure was revised to specifically require organic kitty litter to process nitrate salt drums?" [David] Freeman, Nuclear Waste Partnership's chief nuclear engineer at WIPP, asked a colleague in a May 28 email.

Freeman went on to echo some of the possible reasons for the change bandied about in earlier emails, such as the off-putting dust or perfumed scents characteristic of clay litter. But his colleague, Mark Pearcy, a member of the team that reviews waste to ensure it is acceptable to be stored at WIPP, offered a surprising explanation.

"General consensus is that the 'organic' designation was a typo that wasn't caught," he wrote, implying that the directions should have called for inorganic litter.

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Since September 2012, in fact, the LANL packed up to 5,565 barrels of radioactive waste with organic kitty litter but mislabeled it as inorganic kitty litter—16 of these barrels are also highly acidic and contain nitrate salts like the one that burst. It took an explosion before anyone noticed the mistake.

In addition to being horrifying on its own, the February explosion raises serious question about the safety of nuclear waste storage, especially when you consider how "comically simplistic," to use the New Mexican's words, the explosion's origins seems to be. There are many more worrying details in the New Mexican story, including how LANL took other shortcuts in packing the drum and failed to inform WIPP. It certainly doesn't inspire confidence in our nation's handling of radioactive waste.

A few weeks ago, I wrote about the U.S.'s plan (or lack thereof, really) to a build nuclear waste repository that can last 10,000 years. Forget 10,000 years—we're barely storing nuclear waste safely now. [Santa Fe New Mexican]

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Top image: Undated photo of WIPP. AP Photo/HO