I cannot in good faith go without writing an update on this issue, given the new information made available to the public. Now, the worst sounding of these news stories (the first link) consists of unofficial information, leaked to the press. The basic summary, according that news story (and since reported in a great many places, including the PBS Newshour) was that the fuel in Reactor 1 melted very shortly after the loss of power, and may have violated the integrity of the pressure vessel (there has been some throwing around of the word 'containment' in an unclear way in the press, which is not helpful). There has also been a substantial uptick in the estimated amount of radiation released.
Now, a few points here: Firstly, the last news story linked above suggests that TEPCO does not believe the pressure vessel was seriously violated, which is in line with what happened at Three Mile Island as I discussed briefly before. Second, all of the information reported thus far has been based on estimates of what took place, the size of potential breaches, new information obtained by the recalibration of instrumentation on site, etc. What this means is that these new numbers are potentially not much better than the previous, and in keeping with much of the data presented by the Japanese, is something of a worst case.
Showing posts with label fukushima. Show all posts
Showing posts with label fukushima. Show all posts
Wednesday, June 8, 2011
Saturday, March 26, 2011
Things are looking rough for Fukushima Daiichi, but not all bad news
Earlier this week, some workers at the Fukushima plant suffered from radiation burns when highly contaminated water got inside their protective clothing, as they waded towards a repair site. This prompted the ever cautious Japanese officials to warn that this might indicate a partial loss of containment.
My initial feeling about this was that it was very unlikely. Possible, yes, but not terribly likely, given that a breach of the pressure vessel would have drastically impacted efforts to circulate cooling water (pressure would drop rapidly and significantly, and probably stay down, regardless of how much water was pumped, for instance, which would be immediately detectable). It appears that my gut feeling was correct. While they haven't pinned down the source of the water yet, I'd put my money on damage to the reactor cooling system, which has likely developed a number of leaky valves, gaskets or pipes. The cooling system plumbing has been exposed to multiple hydrogen explosions, earthquakes, debris, and the corrosive effects of seawater. Enough water has been moving through it for a long enough period that even a relatively small leak of water containing fission products from the reactor will have had time to accumulate to dangerous levels inside the plant.
This radioactive water poses a problem to workers, first and foremost, and will significantly complicate repair efforts. Unfortunately, it may also pose a fairly significant environmental risk, depending on its source. If the leaks are occurring in places where the leaked water can come into contact with hot components, or if the leaks are a mixture of steam and water directly downstream from the pressure vessel, then a small, but significant amount of fission products (the main concerns are Cesium and Iodine, but in the long term, primarily Cesium 137, which has a half life of 30 years and has a decay chain that includes gamma decay) may be being dispersed from the plant. Even small amounts can accumulate over time in the near vicinity of the plant, and make uses like agriculture problematic for the near term future. It should be stressed that only water soluble products are likely to end up in the cooling water, so that means no plutonium or uranium are likely to be dispersed by the leaks, which is a very good thing.
My initial feeling about this was that it was very unlikely. Possible, yes, but not terribly likely, given that a breach of the pressure vessel would have drastically impacted efforts to circulate cooling water (pressure would drop rapidly and significantly, and probably stay down, regardless of how much water was pumped, for instance, which would be immediately detectable). It appears that my gut feeling was correct. While they haven't pinned down the source of the water yet, I'd put my money on damage to the reactor cooling system, which has likely developed a number of leaky valves, gaskets or pipes. The cooling system plumbing has been exposed to multiple hydrogen explosions, earthquakes, debris, and the corrosive effects of seawater. Enough water has been moving through it for a long enough period that even a relatively small leak of water containing fission products from the reactor will have had time to accumulate to dangerous levels inside the plant.
This radioactive water poses a problem to workers, first and foremost, and will significantly complicate repair efforts. Unfortunately, it may also pose a fairly significant environmental risk, depending on its source. If the leaks are occurring in places where the leaked water can come into contact with hot components, or if the leaks are a mixture of steam and water directly downstream from the pressure vessel, then a small, but significant amount of fission products (the main concerns are Cesium and Iodine, but in the long term, primarily Cesium 137, which has a half life of 30 years and has a decay chain that includes gamma decay) may be being dispersed from the plant. Even small amounts can accumulate over time in the near vicinity of the plant, and make uses like agriculture problematic for the near term future. It should be stressed that only water soluble products are likely to end up in the cooling water, so that means no plutonium or uranium are likely to be dispersed by the leaks, which is a very good thing.
Friday, March 18, 2011
The Fukushima Nuclear Crisis, and a Crisis of Journalism
This was not what I had intended to write about in this blog, but better to begin writing in it than not writing in it, I suppose. I will turn soon enough to matters of urban ecology, bees, soil preservation, and all manners of such goodies.
But right now I will be talking about Japan, nuclear power, and journalism.
Because frankly, much of the coverage of the situation has been deeply infuriating, as it boils down to a great deal of uniformed fear-mongering, at a time when there are other aspects of the disaster could bear more focus. Even my beloved PBS Newshour has been guilty of this to some extent, though they have for the most part been quite reserved in their pronouncements, and their experts have mostly actually been experts.
But it's a clear indictment of the state of mainstream journalism, that they mostly can't get it together, and are choosing to focus on what is the flashiest, but ultimately likely to be the least important aspect of the aftermath of the Japanese quake and tsunami.
But right now I will be talking about Japan, nuclear power, and journalism.
Because frankly, much of the coverage of the situation has been deeply infuriating, as it boils down to a great deal of uniformed fear-mongering, at a time when there are other aspects of the disaster could bear more focus. Even my beloved PBS Newshour has been guilty of this to some extent, though they have for the most part been quite reserved in their pronouncements, and their experts have mostly actually been experts.
But it's a clear indictment of the state of mainstream journalism, that they mostly can't get it together, and are choosing to focus on what is the flashiest, but ultimately likely to be the least important aspect of the aftermath of the Japanese quake and tsunami.
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