Yesterday (Eastern Daylight Time), TEPCO reported that spent fuel cooling pumps had been started for both the Unit No. 3 pool and the “common” spent fuel pool. The Unit No. 3 pump start-up was reported here yesterday from a TEPCO press release, and the common pool cooling pump report was in a release three hours later (after I entered yesterday’s update). As it turns out, the common pool pump was actually started some two hours before the Unit 3 pump. I wonder how TEPCO could possibly have initially reported in reverse order? Regardless, the most recent TEPCO news release has the respective pump start times in the correct temporal sequence.
In addition, a Union of Concerned Scientists report and Kyodo news report have verified a prior IAEA report that all of the fuel cells were removed from Unit 4 reactor vessel long before the tsunami hit. Total core defueling happened three months ago. The entire fuel core. It was done in order to perform scheduled maintenance on instrumentation internal to the reactor core. Some of the instrumentation was being replaced with new equipment, which is a lengthy, tedious job. Removing all of the core’s fuel cells is not uncommon, but not typical either. Regardless, my statement that only a third of the cells had been removed, based on my prior understanding of standard practice, was incorrect. My apologies to you all, once again.
However, this is actually GREAT news. If I’m wrong about something, I want it to be in favor of the good rather than the bad. This is good stuff. The removed cells had been non-fissioning for three months before the tsunami, thus their decay heat generation rate was very, very low. It is highly unlikely that any theoretical cell uncoverage could ever have caused the cells to be melted catastrophically. But, there was still enough heat to potentially cause enough damage to the outer Zirconium cladding tubes, sufficient to release fission products into the pool’s water, if the fuel cells were actually uncovered. If this were the case, through high temperature evaporation the fission products (including Iodine and Cesium) would get released into the atmosphere. Further, there was never any chance for meltdown of Unit No. 4’s reactor, or it’s fuel cells in the spent fuel pool…neither the realistic Three Mile Island meltdown scenario nor the fictional “catastrophic” meltdown the American news media perpetually mentions.
Next, steam was seen emanating simultaneously from the tops of all four stricken Units. TEPCO and the Japanese media all report that it’s because of on-going spent fuel pool evaporation. When the pools warm up enough for sauna-like evaporation, the steam wafts out to the atmosphere since the building’s have all had their refueling deck levels damaged. Unit 1, 3 & 4 literally have no walls or roofs, so steam emanation is unhindered. Unit 2’s walls and roof are still intact but there are some holes for stem to pass through, probably caused by flying debris from the refueling deck explosions of adjacent Units 1 & 3. Regardless, when the steam is noticed coming out of a structure, water spraying re-initiates and the steam eventually stops coming out. The steam from all four buildings stopped a period of time after spraying resumed. The sprays both replenish any pool level that may have been lost due to evaporation, and cool the existing water in the pools through natural thermodynamic convection.
Concurrently, TEPCO interviews with the Japanese news media now explain the worker “evacuation” reports we have all heard redundantly for the past week. When steam is first seen coming from a building (or buildings), any workers at or near the building(s) move to a further distance from the building(s) until it is verified that radiation fields have not increased due to the steam. Then they go back to work. This is good and prudent, albeit standard Health Physics practice to minimize the possibility of excessive exposure. But, there was has only been one temporary full site evacuation of non-essential personnel, up to this point. The rest of the “evacuations” were as described above. Why are these prudent “people moves” called evacuations? Because that’s what TEPCO calls them in their news releases! They surely could use a better term or phrase, but they don’t.
In addition, the Fuel Pool Cooling and Cleanup Systems for Unit 2 and Unit 4 were used to “inject” water into pools 2 and 4 yesterday. When these systems were actually re-energized and placed in an operational condition doesn’t seem to be mentioned in the TEPCO news releases. <sigh>
But the crux of today’s update concerns the numerous reports now buzzing through all information sources, including TEPCO press statements and the Japanese news media, over the serious contamination and high-exposures to two workers, and non-contamination but high exposure to a third. All three were working together in the basement of the long turbine-generator building that spans from Unit 1 to Unit 4. They were working below Unit #3’s turbine. They are not TEPCO employees. Rather they are employees of some other company contracted as a “cooperative company” (TEPCO term). The three workers were involved in stringing (“laying”) emergency power cabling through the turbine-generator complex. All three were standing in 6 inch deep water (15 cm). All three were wearing anti-contamination coveralls, gloves and head-covers. One worker was wearing water-repellant high top boots. The other two were wearing standard work shoes, without any shoe-covers. Tall three were standing in the ankle-deep water for at least 40 minutes, soaking the shoes and feet of the two who wore shoes only, as well as the bottoms of their pants under the coveralls. Both received apparent burns to their ankle areas.
They were standing in highly contaminated water, with significant concentrations of radioactive Cerium, Lanthanum, Barium, Cesium, Iodine, Technetium, and Cobalt (TEPCO news release). These are all fission products that can only come from heat-damaged fuel. The two wearing only shoes, and their wet clothes under their coveralls, were seriously contaminated. Plus, their radiation exposure levels measured by the dosimeters they wore, were between 170 and 180 millisieverts (17 and 18 REM), which is not life threatening (nor health threatening, using radiation hormesis-based modeling) but is way above the limit for contracted workers who have not been extensively trained in good Health Physics practices. These exposures (to all three) are below the limit for emergency work (250 millisieverts/25 REM), but it seems these three were not cleared to reach the emergency limit.
How could this have happened?
TEPCO reports in their news release, and verbal reports to the Japanese news media, reveal one of the worst cases of poor Health Physics (HP) practice I have ever heard of! First, the two contaminated workers should never have been allowed into the turbine basement without full, head-to-foot anti-contamination attire. At the very least, their shoes should have been covered with thick, waterproof plastic booties, sealed tightly at the top with high-tack duct tape, overlapping their coveralls. AT THE VERY LEAST! Further, their anti-contamination attire should have been thoroughly inspected by a Health Physics professional before letting them go into the workspace, to insure it was properly worn and completely free of open cracks, tears, or holes. Clearly, they were either not inspected, or if they were it was a damn poor inspection! (Pardon my glibness) The third worker wore high-top rubber boots which, while not optimum HP attire, was infinitely more appropriate. The third work’s boots were contaminated, but he and his clothes were not.
To make matters worse, all three workers heard their dosimeters alarming, indicating that they had reached their radiation exposure limit. The single-most important HP behavior for any nuclear worker is to never, ever, think the dosimeter is faulty. NEVER! Leave the area of work immediately, get to a known low exposure access point, and find out if the dosimetry equipment is or is not faulty. In the case of all three workers, they ignored their dosimeter’s alarming, assuming that all three of their sets must have malfunctioned. Back in the day, a trained American nuclear professional ignoring a dosimetry alarm would have committed a career-ending sin. It’s that serious! With contracted workers, before they ever begin to even suit up for entry into a contaminated or potentially contaminated area, they are to receive thorough HP indoctrination on personal protection and the proper donning of anti-contamination attire. They are to be tested, and pass said testing, before ever coming near a work-area’s entry point. Throughout the indoctrination, the “never-think-your-dosimeter-is-faulty” dictum is to be repeatedly emphasized to insure that no-one will ever violate it. These three did! This strongly suggests poor indoctrination by the responsible HP professionals at the scene, in addition to poor pre-entry inspection of anti-contamination attire.
As a former HP professional myself, I’m more than disappointed. I’m mad as a junk-yard dog!
The two contaminated workers showered long and hard until no contamination remained on them. Their clothes were thoroughly laundered, removing the contamination from them. While disrobing to shower, both contaminated employees were discovered to have reddened skin around their ankles. Visual inspection identified the reddening as burns. To be on the side of safety, it was assumed the burns resulted from the beta radiation emanating from the radioactively-hot pool of water (TEPCO calls it a puddle) they were standing in, and had their feet soaked in for as long as 40 minutes. Betas cannot penetrate the skin, in fact they cannot penetrate thin tissue paper. They are not a penetrating form of radiation. Since our outer layers of skin are dead tissue, we naturally wear an excellent beta radiation shield over our entire body. However, if the surface of a pool of water that (after-the-fact readings) shows a 400 millisievert (40 REM) dose for one hour of exposure, then the actual skin dose for beta from the pool must be several times greater, or more. The beta dose to the skin must have been substantial in order to redden the skin enough to be identified as a burn.
Was there a meticulous HP scan of the area using sensitive portable equipment just before the workers went in? Good HP practices demand that this occur. No exceptions. The most recent area scan of the area the workers were in could not have been immediately before entry, and it is unthinkable that a 6 inch deep pool (puddle) of water would not have been closely checked, especially one as radioactively-hot as this one. The workers said they ignored the dosimeter alarms because the most recent scan was essentially clean of any potential “hot spots”. I want to know how long before entry that scan was performed. A six inch deep “puddle” of water doesn’t materialize fast, especially when none of the equipment is running. And that pool provided a radiation field no one could have missed, no matter how incompetent.
All three workers have been transported to nearby medical facilities for examination, plus close medical examination of the two contaminated men to establish whether or not the burns were in fact from beta radiation (they might not be, but why assume it isn’t?).
Regardless, this should never, ever have happened. A clear case of inexcusable human error and HP incompetency!
Finally, in a related news story, the American Press and several otherwise reputable information sources speculate that the existence of the radioactively-hot, highly contaminated “puddle” of water indicates a leak from the reactor. This is probably wrong. If there is a leak, it is probably from a pipe or system component outside of the reactor vessel and the inner primary containment. The secondary containment might house the source of the leakage, but a leak from the reactor itself is an extreme stretch. Kyodo News (Japan) reports that the Nuclear Industrial Safety Agency (NISA-Japan) believes that while the radioactivity probably comes from damaged fuel inside reactor #3, there is good reason to feel that the reactor itself maintains it’s containment capabilities.