Mar 6 2014, 12:01am CST | by Forbes
The only operating underground deep geologic nuclear waste repository had its first minor accident on Valentine’s Day. It was a small release of radiation that will not harm anyone or have any environmental consequence. Maybe it was the Earth’s way of saying, “Happy Valentine’s Day. I love you, but take me for granted and I’ll slap you upside the head.”
The amount of radiation released into the environment was a million times less than any EPA action levels, but to hear the outcry you’d think it was Chernobyl. On the other hand, the general public has become aware for the first time in 15 years that the United States has a successful permanent deep geologic repository for nuclear waste, the Waste Isolation Pilot Plant, known as WIPP. Maybe this will get serious dialogue going.
WIPP is presently licensed only for nuclear bomb 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 Permian-age salts 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 being 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 and ever, debate has been going on to expand its present mission to include high-level waste. This event doesn’t change that.
WIPP has disposed of about 80,000 cubic meters of nuclear waste, some quite hot, and has been operating for 15 years without incident. Until Valentine’s Day, when there was a minor radiological release sufficient to be seen in air monitors at the surface. The signature of Pu and Am makes it certain to be from the transuranic nuclear bomb waste.
We won’t know for certain until we get back in (a process that will takes weeks to months because we want to be really, really careful) but the only event we can think of to produce even this small amount is a large rock fall from the ceiling (or back) of Panel 7 that crushed one or more drums and caused a puff of material that was picked up by the 425,000 cubic feet-per-minute ventilation system and whisked down the exhaust system.
Immediately, the Continuous Air Monitors (or CAMs) alarmed, and the ventilation switched to HEPA filtration that removes about 99.97% of particulates (this type of radiation is always in particulate form so can be filtered). 99.97% is not 100%, as anyone with bad allergies knows, and that difference is what was released.
NMSU’s Carlsbad Environmental Monitoring and Research Facility (CEMRC) independently operates a series of air, water and soil monitoring and sampling stations in and around WIPP (www.cemrc.org). Air filters at these sites were collected and tested as soon as they could (see Figure). The Far Field Station, 11 miles away, did not show anything but natural radiation at any time before or since the event.
Air monitors a hundred yards away from the underground air exhaust point (On-Site Station), and monitors just outside WIPP’s fence line a half-mile away (Near Field Station), exhibited some radioactivity. They both had trapped several days of air flow from before the event to after the event, and showed about a Becquerel (Bq) total of radiation coming from Pu and Am. The natural background radiation collected by these filters for that amount of time is always about 40 Bq.
The On-Site filter had 0.00013 Bq/m3 total from Pu+Am and the Near Field had only 0.00006 Bq/m3 from Pu+Am. The EPA action level is 37 Bq/m3.
So these levels of Pu and Am that got out to the environment from this WIPP puff are a million times less than any environmental concern and 40 times lower than ordinary background. They pose no concern whatsoever. After removing these filters from the field to analyze them, new filters were put in, and these are being analyzed and replaced regularly, as has occurred for the past 16 years. A week after the event, the radiation at these stations had decreased by a hundred times, and soon will not even be detectable, demonstrating no long-term environmental effects.
Just today, CEMRC released the results from filters right at the underground air exhaust point, both just before and just after the HEPA filters, called Station A and Station B, respectively (see figure). These filters are designed to show just how much radiation left the underground and how well the HEPA filters worked to trap it.
The filter removed the morning after the event at Station A showed high levels of radioactivity, as expected, about 2,000 Bq/m3 of combined Pu and Am. Twelve hours later, the new filter showed about 150 Bq/m3 of combined Pu and Am. By the morning of February 21st, these levels had dropped to 0.7 Bq/m3.
Station B showed much lower levels, about 2.03 Bq/m3, when it was collected on February 18th. Three days later it was about 0.13 Bq/m3. Again, not dangerous, and less than the EPA action levels of 37 Bq/m3.
These results clearly show a pulse of material that drops off exponentially with time, and that the HEPA filters trapped most of it. The ventilation system worked exactly as designed.
Of the people working at the site, thirteen received a very small dose, so small that it took a few days to determine they got any at all. An amount so small it takes days to weeks to even measure it using the most sensitive equipment on the planet. That equipment, not coincidentally, is right there in Carlsbad at CEMRC, built for just this kind of event. Since the most concentrated puff of air that got away from the exhaust point and trapped on the nearby On-Site filter was much less than 1 Bq/m3, these people probably did not received a dose anywhere near the EPA levels. But we will find that out in a few weeks as the ultra-low analyses slowly move through the laboratory.
Because it’s so difficult and time-consuming to measure radiation this low, it has seemed that DOE has been releasing information in dribs and drabs, something that has garnered them some criticism, especially concerning the thirteen exposed workers. At first, it seemed there was no one contaminated, then there was, etc.
But that’s only because the info is being obtained in dribs and drabs. For all that the public loves speculation and has no patience for reality, it takes awhile to determine what actually happened. For the thirteen workers that had a measureable amount of contamination (many of us in this field have had this amount or more with no effects), initial measurements on the outside of the people, usually the highest amounts, didn’t show anything above detection and we thought, “great, no contamination”. But the contamination was so low it took days to begin measuring it internally, and will take weeks more to determine just how low it was.
Because safety is everything and we don’t want any other issues to occur, we will go very, very slowly upon re-entering the underground. Since the waste will be there for millions of years, a few months won’t matter. However, we know how to safely re-enter the mine right now to assess the situation. If we were allowed to make technical decisions like this without the political pressure that is surrounding this minor event, things would go faster and easier.
A key consideration here is that we can measure radiation at any amount. You need trillions of atoms of mercury, lead or any other toxic chemical to see them at all, but we can see one atom disintegrating.
The good thing is – we can see every atom. The bad thing is – we can see every atom.
This double-edged sword makes it difficult for the public to evaluate anything associated with nuclear and makes everyone freak out every time something happens, no matter how small. Even though the health effects of this amount of radiation is less than many Americans received from eating potato chips on that same day (a bag of potato chips has 3,500 picoCuries of radiation from K-40), we will assume the worse and move carefully from there.
However, we did design for this. The ventilation system worked as planned, since only fresh air goes over people before going over waste, and once over waste never again sees people. Once the monitoring picked up radiation, the switch to filtration was seamless. The amount of radiation received by any worker is well below the range we allow for workers at any rad facility. I wish any other industry could say the same on any day.
Of course, WIPP’s 15-year perfect operational record will get lost in this one event, no matter that no one and nothing will be harmed. The cries of “shut WIPP down” or “We can’t expand its mission now to include high-level waste” have already begun. Ironically, spent fuel or glass logs would have fared much better, as they‘re solid and would not have been aerosolized if hit with a slab of rock, and the emplacement design is so different that a slab couldn’t fall because there won’t be a ceiling.
This event was an operational issue about filling the repository, not a performance issue about how it will work for the next 250 million years. In fact, this event shows just how well the repository will work. Caving off the ceiling is what happens as the rooms collapse into themselves, followed by plastic creep which crushes all the space out as it becomes molecularly tight once again. We know this happens. We know it was going to happen. It’s just never happed so quickly, before we filled the room and got out.
If you really need to get upset about risk and safety, let’s review a few things that have happened in the United States in the 15-years that WIPP has been operating:
- over 225,000 dead and $1.5 trillion in direct health costs from using coal (The Toll From Coal)
- 80,000 cubic meters (about 500,000 55-gallon-drums-worth) of nuclear waste disposed at WIPP, one minor release of a small amount of contamination on this last Valentine’s day, zero deaths, zero health effects, zero environmental contamination.
And folks want to shut WIPP down? Or think WIPP has a real problem? What Disneyland criteria do you want to apply to this repository, that doesn’t get applied to anything else?
Americans have gotten into a bizarre habit of expecting perfection from this Universe. WIPP has worked better than anyone could have expected, better than we all expected, and this one minor event hasn’t changed that in the least.
We’ll see exactly what happened in a month or so, adjust the operations to prevent it from happening again, and resume operations. In the next several years, we’ll negotiate how to dispose of all our nuclear waste at WIPP, and all of our nuclear waste will be isolated for millions of years and the environment will never be affected.
Or we’ll freak out and the nuclear waste will stay right where it is everywhere around the country, and the environment will just have to deal with it.
It’s your choice.
Source: Forbes Business
Forbes is among the most trusted resources for the world's business and investment leaders, providing them the uncompromising commentary, concise analysis, relevant tools and real-time reporting they need to succeed at work, profit from investing and have fun with the rewards of winning.
blog comments powered by Disqus