Airborne radiation at WIPP
Update: A reader pointed out that the headline is inaccurate. The issue at WIPP is airborne contamination (by radioactive material), not airborne radiation. In order to be gentle with search engines and existing links, the headline will remain as is. End Update.
On Friday, February 14 at 11:30 pm, a continuous air monitoring alarm went off at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM. The alarm indicated the presence of radioactive isotopes in the air inside the facility downstream of where waste is being stored. On Thursday, February 20, the Carlsbad Environmental Monitoring and Research Center reported that it had found trace levels of americium and plutonium at a monitoring station approximately 0.6 miles from the facility.
WIPP is an operating underground waste repository that is designated as a permanent storage location for transuranic — isotopes of elements heavier than uranium — waste generated by defense-related activities. WIPP’s storage caverns are located more than 2,000 feet below ground in an ancient salt deposit.
There was no one inside the facility when the air monitors alarmed. There have been no injuries or exposures reported. WIPP’s ventilation system immediately shifted to an air recycling mode that prevents air from inside the facility from reaching outside.
This is the first time that the air monitors have alarmed inside WIPP during its 15-year operating history, though there have been four past instances when environmental airborne radiation measurements taken near the site have exceeded the usual background level. In each of the previous cases, the source was eventually traced to fallout from the nuclear weapons tests that were performed during the 1940s through the early 1960s.
According to a February 18 story in the Current Argus News titled WIPP awaits analysis of radiation, the facility operators have not been able to report the cause of the facility’s elevated airborne radiation levels. The underground portions of WIPP have been inaccessible since Friday, with workers being assigned to different tasks while waiting for the airborne radiation level to fall low enough to allow workers to enter the facility. Some people wondered if the temporary suspension of operations would lead to layoffs or furloughs, but that is apparently not the case.
Despite the suspension, rumors about temporary layoffs were unfounded, said WIPP officials.
“No Nuclear Waste Partnership personnel are being laid off due to the halt in operations,” said Donavan Mager, NWP communications manager in an email. “As a precaution, some site personnel are working at the Skeen-Whitlock Building on National Parks Highway.”
Today, the Carlsbad Environmental Monitoring and Research Center (CEMRC) reported that it had detected trace quantities of americium and plutonium on filters that collect air approximately 0.6 miles away from the facility. Here is a quote from their press release:
Following the announcement of the underground radiation detection event by DOE, the air sampling station filter was removed for analysis on Sunday, February 16th at approximately 9:40 am by CEMRC personnel. The filter underwent destructive analysis and radiochemical separation at the CEMRC laboratory and was measured for alpha and gamma radiation activity. Analyses of this filter show that 0.64 Becquerels (Bq) of 241Am and 0.046 Bq of 239+240Pu were found to be deposited on the filter media. The Becquerel is an international unit of measure of radioactivity and is defined as one disintegration per second.
The press release continues with additional details. The filter with the measurable amount of radioactive material had been installed in the air monitoring station at 12:40 pm on Tuesday, February 11th. The previously installed filter was clean; there were no radioactive materials detected. The filter showing detectable levels was removed on Sunday, February 16 at 9:40; it had filtered air for a little more than 33 hours after the initial alarm inside the facility.
According to CEMRC, the measured levels were more than 50 times less than the EPA action level of 37 Bq (0.001 microcurie). However, those levels were higher than previously measured. Since they appeared in close sequence with the facility air monitoring alarm it seems logical to assume that the isotopes detected came from inside the facility.
It is worthwhile to understand the sensitivity of the measurement.
Dr. Russell Hardy, the Director of CEMRC, provided some additional details over the telephone.
The fixed airborne monitoring stations filter 20 standard cubic feet of air per minute (SCFM). With an airflow of 20 SCFM, and a duration of approximately 33 hours between the initial alarm and collecting the filter, the 0.65 Bq of radioactive material reported from the station located 0.6 miles from the facility was distributed in almost 40,000 cubic feet of air.
Analytical processes that can measure 0.046 Bq of plutonium isotopes or 0.64 Bq of Am-241 in that volume of air are designed to almost count atoms.
There are good reasons why it took the CEMRC five days to perform and then announce the results of their radiochemical separation / counting processes. That kind of sensitivity requires a integration process that collects data over a long period of time. Before she can begin the counting process, the analyst must dissolve the filters and then separate the resulting material into its possible chemical components.
The separated samples are counted for gamma emissions for 48 hours. Under normal circumstances, the process uses five days for counting alpha particles, but since there was a known release, the procedure has been shortened to a 24 hour count.
The CEMRC has two other monitoring locations. One located 11.8 miles away from WIPP showed no detectable levels. One that is about 100 yards away from the WIPP exhaust stack was inaccessible until 9:00 am Tuesday, February 18 because the site was closed to all non essential personnel. Dr. Hardy informed me that his team is considered to be “nonessential,” but he persisted in his efforts to obtain access until that permission was granted.
Since the air monitoring equipment was running throughout the time that there was no access, no information will be lost. The access delay merely affected the time when the results will be available.
Soon after Dr. Hardy’s team had collected the filter from the site air monitoring station, CEMRC took delivery of additional air filters from inside the facility. Ten of those filters were in equipment that samples the exhaust stack before air passes through the high efficiency (HEPA) filters that filter air from the operational portion of the facility before it is exhausted to the environment.
Update: (Posted 02/21/2014 at 0324) The underground facility has a ventilation system that draws in 425,000 SCFM of outside air, distributes it through the occupied areas, then past areas containing waste and then back to the environment. There are continuous air monitors that sample the air, both in the spaces where people work and after it passes through areas containing waste.
When the air monitors sense any contamination, that ventilation is immediately redirected through high efficiency particulate absorption (HEPA) filters before being put back into the environment. The flow rate is also reduced by a factor of four to 100,000 SCFM.
Source – Comment from Jim Conca, former Director of CEMRC (2004-2010)
The basis for the design of not always filtering the air is that HEPA filters absorb all particulates. They would get saturated frequently if they were continuously being used to filter 425,000 SCFM even if it was not contaminated. Not only is that an operational and cost issue, but it would not improve safety because the filters would be unlikely to be fully available if they were needed to filter out radioactive contamination.
One of many mistakes made at TMI was that exhaust air was improperly being directed through filters all of the time. Those filters were then not as effective in removing radioactive iodine (I-131) as the designers expected at the time they were actually needed. End Update.
Another set of filters came from sampling equipment located on the other side of the HEPA filter, but still inside of the exhaust stack.
There is only one radiochemist on Dr. Hardy’s staff. That limits the amount of parallel processing that can be done while still maintaining good quality control and producing reliable results.
Because there is a strong desire to understand the exact conditions inside of WIPP, the task of measuring the exhaust stack filters has been prioritized before the third ambient air sample. Dr. Hardy indicated that results from the station located about 100 yards from the exhaust stack will be reported sometime next week.
I want to emphasize one more time that 0.64 Bq of Am-241 is a very small amount of radioactive material; there is no public hazard. The people assigned to monitor WIPP and its effects on the public are taking this event seriously. They are providing the best information they can within the resource constraints available.
Note: CEMRC is a division of the College of Engineering at the University of New Mexico that operates a 26,000 square foot radiochemistry facility. It is under contract with the Department of Energy to provide independent monitoring services in the area around WIPP.
Time is now to get a nuclear spill-over PR handle on this incident early to nip any caustic rumors and malicious speculations in the bud. Here’s the time for NEI and ANI and company to start issuing public enlightenment statements to the media — even if they’re trashed. The antis won’t wait to stain fact with doubt and fear.
James Greenidge
Queens NY
I may be wrong but I really dont see this as a nuclear power issue but one more related to weapons materials.
I was really wondering about this situation but found no info on further investigation. Namely I was wondering what were the dispersal mechanisms. Now that I see the detection is so sensitive I guess it wouldn’t take much to get readings.
No stories I saw referenced any real numbers in what was released or the concentration. I think thats ridiculous Rod by any standard for a industrial incident. It just leads to wild speculation and innuendo.
@John
Though not involving energy production-related materials, I thought it was of interest to Atomic Insights readers. If nothing else, I hope you find the facts useful in answering questions from friends and colleagues.
No doubt. Like I said I couldn’t find any info whatsoever anywhere else despite the rather intense media buz. I think you were one of the few people if not the only person that actually followed up as odd as that seems considering the resources in big media.
At first I was wondering if it had to do with the truck fire there a bit ago, but evidentially not. I guess with detection equipment that sensitive it could be a very minor leak/rupture and dust/gas just stirred around by the ventilation system.
Does anyone know how many Becquerels you would detect from the Am241 in a household smoke detector? It could be a good reference for people who don’t know much about radiation.
@Todd
Smoke alarms contain somewhere close to 35,000 bequerels of Am-241.
You know I found one of those gray phallic D battery radiation detectors in my dads old surplus end of the world stuff and it still worked.
I forget which tube I put in it (gamma(?) I think but being in north central fla in mine-able phosphate/uranium country I expected the plumbing/aeration/holding tanks around my well and water heater to set it off – NOTHING. Rocks, the lawnmower, the car, the dogs, cat, bananas and everything else – nothing either.
But It went crazy next to the smoke detector. Id like to know the answer to that too.
Oh thanks.
Those things had very poor sensitivity. Probably in the neighborhood of the source in the fire detector. Areas that a survey team would have cleared for normal access back then would now be quarantined for life with todays equipment. The newer friskers and portal access monitors can tell if you had an MRI the day before. If it has a headphone jack listen with it out in the open, so as to get background counts. If you do not hear any clicks or fewer than 5 to ten per minute it is rather poor. Try the end of a florescent light bulb (40 watt tube). Years ago that used to be radioactive, not sure any more if they are or not now. An old Fiesta Ware cup, plate etc. that is Orange (orange glazing is from “yellow cake”) will also make it click, but it has to be an old one, like one your mom got when she got married. New ones use a different source for the orange glaze. The increased sensitivity is another problem with ALARA. the sensitivity has probably doubled several times in the last 50 years, probably more like an order of magnitude more sensitive.
The detector that set off the alarm (article above) works like a filter that you would count pollen with. A vacuum pump draws the air through a filter, any particles get trapped by the filter. Next to the filter is usually a scintillation detector (very sensitive, thinner than a razorblade edge) which is on the end of a photo-multiplier tube. Any disintegration of radioactive material will cause the scintillation crystal to fluoresce. That gets amplified by the Photomultiplier tube and makes a count. Usually the filter paper will be changed every day, week, month, on a basis as to what level they are trying to measure. I would bet even money that the filter paper got contaminated while installing it in the detector. The tech could have placed it on the cabinet after taking it out of envelope it was in before installing it in the detector. The ones at TMI would get set off when the wind was blowing toward TMI from the three unit coal burner just three miles south of the plant, for several days in a row.
Great job, Rod. One thing to mention about WIPP ventilation is its great design, 425,000 cubic feet per minute flow that can be diverted to HEPA and then decreased to 100,000 cfm. The system is designed such that air flow is always over people before waste and then exhausted so anything coming from the waste cannot contact people. The system worked beautifully. It will take some time to determine the source, but one incident in 15 years is awfully good. WIPP has disposed of almost 100,000 cubic meters of waste, some fairly high-level (>7 Ci/liter), hotter than anything left in the Hanford tanks. Now WIPP is merely nearly perfect.
Hi Rich, you’re right, these high-volume ambient aerosol collect only particulates, like pollen. But the ones we put at WIPP and environs are special. They are 20 x 25 cm Gelman A/E™ glass fiber filters that collect at a flow rate of ~1.13 m3 min-1. After collection, they’re removed using special handling protocols and taken back to the CEMRC radlabs and analyzed for selected radionuclides, including 238Pu, 239+240Pu and 241Am. Following 6 hr of heating in a muffle furnace at 500° C, which drives off organics, the tracers and the iron carrier are added and each filter is treated with HF+HNO3 up to the complete decomposition of silica. Then it is treated with conc. HClO4 and HNO3 for the removal of fluoride ions. The actinides are then separated as a group by co-precipitation on Fe(OH)3. The nuclides of interest are precipitated with LaF3, deposited onto filters, mounted on planchettes, and counted on an Oxford Oasis alpha spectrometer for five days. Gamma-emitters are measured in the air filters by Gamma spectrometry for 48 hours. We routinely get to the femtoCi level.
An important finding of our earlier studies was that the activity of Pu and the concentration of Al in aerosols were correlated and this was driven by the resuspension of dust particles contaminated with radioactive fallout from past nuclear weapons tests. Similar results were found for Am and Al. Related studies of soils collected on and near the WIPP site have shown that correlations exist among Al and both naturally-occurring and bomb-derived radionuclides including 239+240Pu.
If you’re interested, check out the annual reports at http://www.cemrc.org (I was Director there from 2004 to 2010). It is a very nice facility with great scientists.
@Rich Lentz
I would bet even money that the filter paper got contaminated while installing it in the detector. The tech could have placed it on the cabinet after taking it out of envelope it was in before installing it in the detector. The ones at TMI would get set off when the wind was blowing toward TMI from the three unit coal burner just three miles south of the plant, for several days in a row.
The detector with the reported levels was from a monitoring station located six tenths of a mile away from the WIPP exhaust. There is little to no chance of it having been accidentally contaminated. The isotopes measured could not have been coming from burning coal; they are not naturally occurring.
Note: Am-241 is, of course, an isotope that has widespread commercial and residential use and can probably be detected occasionally from places like incinerators.
As a chemist, let me thank you for that fascinating glimpse into the sort of routine yet highly specialised analysis involved in radiological monitoring.
“can tell if you had an MRI the day before”
Quibble: MRIs don’t use anything radioactive. Perhaps a PET scan?
Not to start an argument, but there are only 2 cams underground. Maybe 7 PAS samplers. The only air monitored is from the exhaust of active panels.
If the ventilation worked and flowed as designed, there shouldnt of been hours of smoke pouring out of the salt shaft the day of the fire.
Lastly, and I too speak from experience, how much plutonium-radioactive isotopes in your lungs is ok? NONE We all know why the action limits are there, and putting icing on a dog turd does little to change the fact it is still a turd. Keeping workers on site without at least a mask is incomprehensible! Your sampler that picked up “traces” of contamination was not in direct path of the current wind pattern. We know there was no plume that was released, so therefore what made it onto your sampler was extremely small of what settled on site, got blown around by traffic (as the road is still open) and then deposited on your awesome filter.
Long story short, with 4.5 million at station A, there is no way to decon the exhaust and panels. Think what the area must look like in terms of numbers if there is that type of activity at stat. A……from the room to the exhaust around the corner, back half a mile and then straight up half a mile…..Riiiiiight…
Jim, thanks for some interesting details. It is depressing to see how much of our money is being wasted pandering to the irrational fear of very low level radiation, making nuclear technology more expensive than it should be.
The nuclear industry should produce a guideline for writing press releases about radiation emissions that include practical comparisons like the smoke detector, medical tests using radiation, average radiation in the human body, 5,000 bq.
How many minutes of operation of the coal plant at Farmington NM would it take to equal this release?
@Just a second
I hope you plan to stick around long enough to become involved in discussion. We generally frown on “drive by comments” that start off offensively without anyone to provide clarifications.
Are you a resident local to WIPP?
@Just a second
You wrote:
If the ventilation worked and flowed as designed, there shouldnt of been hours of smoke pouring out of the salt shaft the day of the fire.
Who said the ventilation system was supposed to prevent smoke from leaving the facility? If you worked underground and there was a fire, wouldn’t you appreciate a little fresh air? How quickly do you think that HEPA filters would become saturated if someone attempted to use them to clean smoke?
In other words, I’m guessing that the ventilation system design does not call for the system to shift to filters or to recirculation mode in the case of a fire. Do you have different information about the system specifications?
@Just a second
Lastly, and I too speak from experience, how much plutonium-radioactive isotopes in your lungs is ok? NONE
Are you trying to tell me that everyone who breathed air during the period from 1945-1963, when the atmospheric test ban treaty was signed, should have been harmed by internal exposure to plutonium? Do you think the material released during that extensive testing program, which resulted in the explosion of about 2,000 nuclear weapons, has somehow disappeared?
Have you ever heard of the IPPU group of workers who accidentally inhaled substantial quantities of Pu during the bomb manufacturing process in the 1940s and 1950s, yet were still alive well and being monitored well into the late 1990s?
Here is one of the earlier documents about the studies conducted on that group of people, but there were follow on studies as well.
http://www.osti.gov/scitech/biblio/4582895
(Note: Link changed to better copy of same document.)
@Just a second
Long story short, with 4.5 million at station A
4.5 million WHAT? Numbers without units are useless.
Correct. should have been PET or CAT as I believe that also requires an injection of a tracer. Not a doctor and only had one of those in my life.
Now I am, confused. How does a Continuous Air Monitor alarm work continually if you have to take out the filter and do every thing you said? Both Rods article and the linked article refer to an alarm on a “Continuous Air Monitor.” That to me means there is a detector facing the “dirty,” collected side of the filter medium.
Or are you describing what takes place AFTER one has alarmed and the facility wants to determine exactly what caused the alarm?
And is there any possibility that the various (MANY) nuclear tests contaminated the soil in that area? Quite a few that the government has released the location of. And how many have they not released the location of? Trinity was above ground and near White Sands missile Site. There were others in NM.
THANKS! The stuff about the TMI detectors and you guys subsequent conversation was extremely interesting.
The detector I found (I braved the mega palmetto bugs to retrieve the manual as I couldn’t find searching on line) is bare bones for sure. None of those highfalutin meters or lights – just sticky earphones.
( http://www.radiology-museum.be/English/Collection/RecordInfoObject.asp?Record=O-571 )
The gray tube and the thiner extension that has the detector tube are all you carry around with the headphones coming out of the back. As one might expect the whole thing also vibrates when you turn it on.
I may have some old florescent tubes in the shed to try it on. I might have some of those old lantern mantels as well (they had a little thorium at one time). I ll break out again sometime.
Anyway when I was looking on line for this one I noticed a plan for a homemade one that is rather simple yet kinda interesting. Evidentially you could make it on the fly for those annoying nuclear wars that occurred before you had time to shop and prepare:
Kearny Fallout Meter ( http://en.wikipedia.org/wiki/Kearny_Fallout_Meter )
The Continuous Air Monitors (CAM) view the collection filter in real time with a ‘surface barrier diode’ alpha detector. The intake air with particles is drawn aerodynamically around the disk detector and impinged on the surface of the filter. The detector has sufficient ability to sort the various alpha energies from 241Am/238Pu and 239/240Pu along with various short lived progeny of 220/222Rn, most of the time. There are technical issues with dust overmass on the filters over time as well as interference from straggling energies of the radon progeny. (The air between the filter and the CAM detector is also ‘overmass’.) That’s the natural environmental stuff and is a confounding interfering background for the live performance. In order to overcome the interference of overmass, the filters are changed periodically for retrospective assay as Dr. Conca describes The former is in-situ, the latter is destructive in the lab. Due to the ultra low incidence of material, it takes a lot of effort to perform the real time as well as the lab activity. It’s not cheap, but it’s VERY sensitive. Sensitivities with the high volumes are typically less than 2e-14 uCi/ml, not very many atoms.
There is some additional logic about ‘how much’ Pu is (not)ok in the lung. The regulatory (10CFR20) airborne limits for 239/240Pu are 2e-12 and 2e-14 uCi/ml for worker and public respectfully. There is one alpha decay per decaying atom of Am or Pu; the energies are approximately 5.48 and 5.12MeV respectively. The Pu is considered to be in hard particles, most of which is caught in the upper human airways and expectorated, natural reactions to dusty environments, great design.
Now consider radon progeny. These are really tiny because they come from radon gas as single atom decays. These are with us every live minute of our lives. As gas, the atoms are drawn into the deep lung, right on past the aforementioned barriers. So, (with a little hand waving) one should have a constant concentration comparable in ratio to ambient air. There are 6-8 rapid alpha decays in the radon progeny chain depending on how you count and the level of equilibrium. The worker and public airborne limits for radon are (with progeny) (220Rn) 9e-9 and 3e-11 uCi/ml and (222Rn) 3e-8 and 1e-10 uCi/ml respectively. That’s about a 1000 times higher than for Pu and with more potential decays! Most of the alpha decays are above 6 MeV with one at 9 MeV!
As to why the difference in regs? Well, it’s kinda hard to control radon below natural. So, the limits were set somewhere near there. But for the man-made, we go overboard. I’ve never really gotten a satisfactory answer from health physics on this one, I’m just a nuclear chemist.
Looked at those articles. Looks a little like building a boat in a bottle (difficulty wise.)
I made a Neon Lamp Relaxation Oscillator while on the sub. Got it to count exactly 100 times per minute away from the reactor. I noticed that when I carried it toward the Reactor compartment it sped up enough to notice that I was blinking faster. Don’t remember the count but was amazed it did. Years later I determined that Neon lamps have what the manufactures call “dark effect.” You have probably noticed that on the inexpensive power strips that when it is dark the power lamp is off, but if you turn on the lamp in the room or shine a flashlight on the power strip it glows again. That is “Dark Effect.” I guess the radiation from the reactor lowers the ignition voltage of the lamp and thus it blinks faster.
Perhaps that could be “calibrated” and used as a warning device. Could even be adjusted so that it would not blink at all unled the radiation was at or above a “safe” limit. Would require a calibrated power source though. Mine was just 5 or six used 22 volt batteries that were used in one of the instruments onboard.
A still better copy of the same document can be found here:
http://library.lanl.gov/cgi-bin/getfile?00402315.pdf
It was 4.4MBq, agreed, I detest numbers without units.