Did Organic Cat Litter Cause a Nuclear Waste Leak? Scientists are Still Unsure
It was not well covered, but on February 14, 2012 a 55 gallon drum of nuclear waste buried in a one-of-a-kind deep waste disposal facility burst in New Mexico. Sensors detected airborne radiation and 21 above-ground workers in total were exposed, but fortunately it was a low dose and they should all be fine. It was also fortunate that nobody had been below ground. The facility however, may be shut down for 18 months or longer as technicians work to secure the site.
The Waste Isolation Pilot Plant in New Mexico is the nation’s only dump for nuclear weapons waste. The site was dug as a conventional salt mine with additional rooms to handle the waste. It was designed to collapse and contain the radioactive materials for at least ten thousand years. Prior to this even the mine operated incident-free for fifteen years.
The waste involved was primarily nitrate salts, a byproduct of the chemical process that extracts plutonium for use in hydrogen bombs. Preliminary investigations indicated several safety violations as unapproved procedural changes had been made during packaging at the Los Alamos National Laboratory (LANL).
The change initially thought to be the culprit was the switch from inorganic to organic cat litter used to neutralize the waste. Someone apparently wanted to be “greener.” Jim Conca, former geologist at the WIPP explained why this is potentially problematic in a blog post.
“Nitrate salt solutions can ignite when they dry out – which is why it’s tricky working with nitrate solutions in the lab and why you need to make sure they don’t dry out, something many a chemistry student has found out the hard way. So you need to stabilize nitrate solutions before they dry out, or prevent them from completely drying out.
Traditional cat litter is made from various inorganic geologic silicate minerals like diatomaceous earth, zeolites or bentonites, materials that are excellent in absorbing and stabilizing chemical species like nitrates, ammonia, and urea. This is the very reason we use minerals for cat litter. Unfortunately, someone working with this waste, before it was to be shipped to WIPP, used a new “green” cat litter, made with materials like wheat or corn. These organic litters do not have the silicate properties needed to chemically stabilize nitrate the correct way.”
This wheat-based organic cat litter not only doesn’t neutralize the waste, but the organic compounds may actually react with the waste and become a kind of fuel source. According to New Mexico’s secretary of the environment Ryan Flynn, there were 500 drums delivered with the incorrect cat litter, though the 499 remain stable at this point. Investigators also discovered a lead glove left in the burst drum, as well as tungsten, acid, and an unauthorized neutralizing agent added by LANL- all things that should not necessarily be mixed with each other and nuclear waste. Six months after the event however, investigators have yet to reproduce the burst drum in a laboratory setting.
Sometimes change is good and sometimes change is bad. The moral of the story here is that change is really not a good thing when it comes to nuclear waste management procedures. The the nuclear technicians probably love their little drums of nuclear waste dearly, but buying organic litter for it does not make you a better nuclear-waste parent.