You might have heard that the most likely culprit for the Valentine’s Day radioactive leak was…kitty litter!
Yes. The wrong kitty litter was probably used to treat some of the nuclear waste recently disposed in the world’s only deep underground nuclear waste repository, near Carlsbad in New Mexico. Cat litter has been used for decades in radiochemistry labs and nuclear facilities to stabilize certain radwastes, like liquid scintillation solutions, evaporator bottoms, and other materials that have nitrate salts in solution.
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.
We still need more visual evidence to be absolutely certain. The drum thought to have burst is about 10 rows back from the waste face. See photo of the waste panel in question. The Valentine’s Day event seems to have originated from a spot where that particular waste stream was placed.
Recall that WIPP, the only operating geologic nuclear waste repository, had its first minor accident on Valentine’s Day after 15 years of perfect operations. It was a small release of radiation that did not and will not harm anyone or have any environmental consequence. The amount of radiation released into the environment was a million times less than any EPA level requiring action, so small that, according to the EPA, we didn’t even have to report it.
Every drum going to WIPP is labeled, barcoded and tracked so we know where they all are and where they came from. We know which drums were treated with this green litter. Some are stored at WIPP and some are stored at other places. We can solve this problem.
Because of this event, the general public has become aware for the first time in 15 years that the United States has a successful nuclear repository, the Waste Isolation Pilot Plant, known as WIPP. It will take a few months for the real story to get out, for everyone to realize that WIPP performed excellently, that this was not the result of any safety lapse at WIPP or any failure of the repository itself. We need to have serious, intelligent discussion in this country about nuclear waste.
WIPP is presently licensed only for nuclear weapons waste, transuranic or TRU, but was designed to hold any and all nuclear waste. WIPP is located a half-mile below the Earth in the massive 10,000 square-mile Permian-age salt deposits of the Salado Formation within the Delaware Basin that cuts across southeastern New Mexico into west Texas.
The Salado has geological, physical, chemical, redox, thermal, and creep-closure properties that make it ideal for long-term waste disposal. Long-term in this case means greater than 200 million years. Because it is the best place, and the best rock, to put nuclear waste, or anything you want isolated from the environment forever, debate has continued on expanding its present mission to include all nuclear waste. This Valentine’s Day event does not change that. Instead, it demonstrates the wisdom of the geological and nuclear engineers who designed WIPP. It is fortunate that this drum was in WIPP and not anywhere else when it burst.
WIPP has disposed about 80,000 cubic meters of nuclear waste, some quite hot, and has been operating for 15 years without incident. The performance basis of WIPP is still excellent.
When the event occurred all experts began to examine anything that might have caused it, from the preparation of drums for storage to the performance of WIPP. The first idea to come to mind was that something caused a drum to open. The only thing we could come up with was that a large slab of salt rock fell from the ceiling of Panel 7 and crushed one or more drums.
But that is definitely not what happened. Instead, nitrate salts in the wrong litter probably dried out sufficiently to burst open a drum, and some material was entrained in the airflow out of the room. Immediately, the underground Continuous Air Monitor alarmed, and the ventilation switched to HEPA filtration, allowing only a small amount to get out and intersect 21 people and some air filters. The levels of Pu and Am released were a million times less than any environmental concern, thousands of times less than any health concern, and 40 times less than ordinary background.
This is the by-product of being able to see a single atom disintegrating. The amount was so insignificant that we couldn’t see it after the first check on the people that showed the initial hit. We’ll keep monitoring them, but there isn’t any concern.
So, as far WIPP itself goes – no health concern, no environmental concern, no safety concern, and now no operational concern. The performance basis of WIPP is still excellent.
It is important that we re-investigated WIPP operations and safety. DOE wrote two detailed accident reports finding issues that should be fixed and a third report is forthcoming. Of course these reports were immediately jumped on by many opposed to WIPP, or anything nuclear, but now we know it wasn’t WIPP after all. The performance basis of WIPP is still excellent.
WIPP and the salt host rock had nothing to do with the drum that burst. A fire three weeks prior had nothing to do with the drum that burst. Transportation had nothing to do with the drum that burst. The salt itself had nothing to do with the drum that burst. It was indeed providential the drum was in WIPP when it burst.
Of course, everyone is frustrated and untrusting, and we can choose to be so, but nonetheless, we need to move forward.
Seal off Panel 6 with the normal metal bulkheads at either end. This will contain any event from these drums. All other drums with green litter should quickly be corralled from where they are, shipped under containment, emplaced in Panel 7 at WIPP and the panel sealed off. It would be the safest thing to do. The energy of this type of event is easily contained in a closed panel, even with minimal closure, and the salt then would creep in, as it is supposed to do. TRUPAC containers are able to contain any energetic event from these drums and could even be used as interim storage containers.
Another important point is that these materials become less stable when they’re heated. So in the mean time, it is important to make sure that these drums are segregated and kept in a cool environment. Summer is coming.
There are many other technical fixes known or being developed, like blast-resistant foams we use to smother bombs, strengthened containers, shielded operating platforms, etc. The best minds are working on this. They need to be listened to. But, if we dawdle in dealing with these drums, and take three years to get WIPP open again, or try to find another place, as is being discussed (3 years), it would not only be a shame, but would cause unnecessary risks and waste billions of dollars.
We overreact every time anything involving radiation occurs, no matter how small, no matter that no one is harmed. It prevents us from taking the proper scientific and engineering actions when they need to occur. We need to act quickly.
The performance basis of WIPP is still excellent.