The Carlsbad Environmental Monitoring and Research Center (CEMRC) has conducted radiological analyses of filters from WIPP, for the period at and a week after the Feb. 14 plutonium release.
These filters consist of 47mm diameter, one micron pore size, paper filters that sample the air exiting the WIPP repository exhaust shaft at Station A (before air goes through HEPA filtration) and at Station B (after air goes through HEPA filtration). As stated by DOE officials, in the event of a radioactive detection in the underground, the ventilation system lowers the fan speed and automatically shifts to a “filtration” mode; whereby all of the exhaust shaft effluent passes through a large bank of High Efficiency Particulate Absorption (HEPA) filters designed to remove 99.97% of all radioactive particles from the air before exiting into the environment…
Additionally, it deserves noting that the engineered safety systems in place within the WIPP facility (i.e. HEPA filtration system) reduced the amount of 241Am exiting the exhaust ventilation system by 754 times and the amount of 239+240Pu by nearly 3,000 times. Lastly, it is also evident that in the days following the event, the levels of radioactivity both within the repository (pre-HEPA) and what was ultimately released (post-HEPA), have decreased considerably and appear to have stabilized at significantly reduced levels.
There were supposedly no workers underground at the time of the release, so the 13 workers who did test positive for americium and plutonium were exposed to levels corresponding to Station B.
If you look at the Station B section, under the column “241Am Bq/m3”, you will see 1.81 becquerels of americium-241 were found in this filter on Feb. 18. Subsequent days have much lower readings, as noted. But if you take the average of the subsequent days, you will find that WIPP is still releasing the same quantity of Am-241 every 13 days.
So according to this data, we are getting WIPPed every two weeks or so. Perhaps the levels have dropped further since then, but we don’t know that for sure.
This article by Don Hancock of the Southwest Research and Information Center (SRIC) has some good information.
As of March 4, there is much more that is unknown than known:
* What caused the leak?
* How much leaked into the underground salt mine?
* How much leaked into the environment?
* Where are those radioactive and toxic wastes now?
* To what amount of radiation were the workers exposed?
* What are the health effects for those workers?
* What decontamination is necessary in the underground mine?
* What decontamination is necessary on the WIPP site and surrounding area?
* If WIPP reopens, what changes in the operation, monitoring, and safety culture will be implemented?…
But it is likely that for at least some of the questions, precise information will never be available. For example, how much leaked into the environment may be only approximately determined. Although computer air dispersion models will be used to estimate the amount released, where those contaminants are is unknowable, since the wind can widely disperse the particles of plutonium (Pu)-239 and americium (Am)-241 that were detected. What precise health effects will occur in workers and others is also unknowable. But health dangers exist for a very long time, since Am-241 has a half-life of 432 years (half of the current radioactivity will be present in that many years), and Pu-239 has more than a 24,000-year half-life.
Multiply the half-life by 10 to get the approximate time that these leaked isotopes will be dangerous. For americium, it is 4,320 years. For plutonium, it is 240,000 years.
On February 26, the 13 WIPP employees who had been on the surface when the radiation was detected were notified that they tested positive for internal radiological contamination, “predominantly americium-241.” These workers will have additional bioassay (urine and fecal) analyses conducted. On Thursday, February 27, Farok Sharif, Nuclear Waste Partnership President, stated that other workers who came onsite on February 15 are having bioassay testing, and some additional workers are requesting to be tested. All workers who want to be tested will be tested. All workers who want to have lung and whole body counts at CEMRC also will be allowed to do so. Laboratory analysis of bioassay samples takes one to two weeks. Sharif also stated that no workers have received chelating drugs that could help excrete the internal contamination.
The 13 workers that were tested were a small fraction of those who may have been exposed. More workers want to be tested, but we haven’t heard of these results as yet. The workers were denied chelating drugs that would have helped excrete the plutonium. These should be administered within 24 hours. No matter, according to the Department of Energy, and its contractor Nuclear Waste Partnership. They say all the americium and plutonium went away from the workers’ bodies. I haven’t heard that one since the government said that all the oil in the Gulf of Mexico suddenly went away after the BP oil spill.
WIPP radiation leak was never supposed to happen — No one knows yet how or why a waste drum leaked […] setting off a cascade of events that could cripple the nation’s radioactive waste disposal system. […] before WIPP opened, the [DOE] put the risk of such an accident at one chance in 10,000 to one in 1 million during any given year of WIPP operations […] only two possible scenarios […] an exploding waste drum or a waste disposal room roof collapse. […] “You could have crapped up a whole lot of real estate down there,” [Bob Neill, a radiation safety expert] said. The underground drum fire scenario […] hypothesized the “spontaneous combustion” of a drum’s contents, rupturing and spreading the radioactive waste inside [a] one chance in 10,000 in any given year of WIPP operations. The “roof fall” scenario […] was calculated at one chance in a million during a given year [and] could leave a large number of waste drums crushed and leaking. […] Cleaning up contamination [would] risk of further spreading the contamination. […] In a formal legal notice, the New Mexico Environment Department said, “It is believed … that the WIPP will be unable to resume normal activities for a protracted period of time.”…
Container Fire — Contents of a drum in an underground disposal room spontaneously combusts prior to panel closure.
Roof Fall — A portion of a disposal room roof falls prior to panel closure, crushing drums and causing container breaches.
There are 100 oil wells within a mile of WIPP. Pumping oil out of the ground could cause subsidence, which could lead to a roof collapse, and the subsequent breaking of drums. Plutonium is dangerous for 240,000 years. But making a quick buck is more important.
The containers could burst open and leak or born also. Gases build up inside the drums. From this study of TRU waste drums in Los Alamos, headed for WIPP, a significant percentage of containers have too much hydrogen or pressure:
As of October, 1997, hydrogen concentrations measured by the DVS were obtained for 323 drums, from a total of approximately 2500 vented drums. Concentrations measured during drum venting have been as high as 23.97%. In one instance when EM&R/HazMat was called to remotely vent a visibly bulging drum, subsequent analysis of the headspace gas revealed a hydrogen concentration of 27.89%.
Hydrogen is, of course, explosive. Who knows how long it takes to build up hydrogen in the drums? This might be a continuing problem for thousands of years. Another study discusses the possibility of gas-driven hydrofractures occurring at WIPP:
Modeling and experiments performed by Sandia National Laboratories show that gas caused by the anoxic corrosion of iron and by biodegradation of organic materials will be generated within the Waste Isolation Pilot Plant (WIPP). A potential exists for several tens of million cubic meters (at atmospheric pressure and 30oC) of gas to be generated. A review of the WIPP Compliance Certification Application (CCA) calculations and associated literature has revealed inadequate consideration of gas-driven hydrofracture. This paper presents the results of both laboratory modeling and mathematical analysis of gas-driven hydrofracture at WIPP, with emphasis upon the behavior of a vertical hydrofracture. The results show that unless special care is taken to preclude the generation of gas or to properly vent gas, a gas-driven hydrofracture is likely. Our physical modeling reveals the development of both horizontally- and vertically oriented circular hydrofractures, even within a horizontally stratified solid. The behavior of a vertical hydrofracture is considered in this paper. It is shown that a vertical hydrofracture would be incapable of containing the gas volumes predicted.
And the waste at WIPP is not limited to americium and plutonium. The tables below (link) show a list of radionuclides in waste headed for WIPP. Cesium-137 and strontium-90 are well represented in here. Many of these nuclides are in gas or vapor form and exist as dissolved gases with the waste. These include tritium, carbon-14, radon-222, iodine-129 and others. The HEPA filters at WIPP only remove particles. They do not remove gases. Charcoal filters are needed to remove gases. Gas emissions continue unfiltered at WIPP.