But saying that in general is not the same as an analysis of the specific incident in front of you. The situation at the plant may have changed drastically in the last few hours, true. It’s not a good situation in any way. But it’s also not like the gulf oil spill, where the problem was nearly inaccessible. The problem is currently being addressed, actively.
Because of events like those in the gulf, we’ve gotten to a point where anybody who isn’t giving a doomsday scenario is automatically disbelieved. I’d think that you as an engineer would be more disgusted by that than most people. That attitude is harmful to everything and everybody.
What beowulff said. They have a serious problem with that reactor and that power station. Which isotopes of Cesium and Iodine are they claiming are “almost gone?” (Quote from Exapno’s quoted report, 5th bullet point) While Iodine 123 has a half life of 13 hours, considering Iodine 131 has a half life of 8 days, and Cesium-137 has a half-life of 30 years, I’m not so sanguine about all of the radioactive gases being “gone,” especially if they’re making statements like,
I have a hard time believing that statement, given the cited half-lives above. What definition are they using for “activated steam?” Does it cover all gaseous radioactive elements that may have been vented? I don’t believe they have a very good handle yet on how much radioactive crap got vented from the reactor vessel and blown out to sea. I doubt they’ve been able to do a fissionable products inventory, and I’d really like to see data from instruments monitoring that gas plume, if there are any at all. Thank God for an offshore wind. I’d be really interested if the U.S. managed to get off its ass and send some sampling aircraft/drones into the gas plume. Considering some of the attempted cover-ups in the Japanese nuclear power industry, e.g. Monju’s 1995 secondary coolant leak, the inspection falsification scandal of Tokyo Electric Power Company’s reactors in 2002 (listed under Accidents in the wiki for Japanese Nuclear Power, I also don’t have absolute faith in assurances that everything is under control or fine. Containment structures don’t explode from high hydrogen concentrations if everything’s fine. (Link has embedded 2.5 minute video, purporting to show the explosion at Fukushima.) Seawater isn’t pumped through a reactor core if everything’s fine. An example of a statement I find misleading, if technically correct, is
Um, no. If fuel elements melted, de-fueling and decommissioning this core is going to be a long way from a regular fuel change, for the reasons previously cited in this thread. If fuel elements melted, see the decommissioning efforts at TMI for an idea of the problems they’ll be facing.
Don’t get me wrong, I am very pro-nuclear power, and I would love to see the U.S. adopt a much larger concentration of nuclear power generation than currently, even after this disaster in Japan. And clearly this is nothing like Chernobyl. But it’s already worse than TMI—I don’t recall reading accounts about TMI of radiation levels within the control room in excess of 1000 times background, do you? Accordingly, these accidents in Japan are serious accidents that are ongoing, and since its ongoing, we’re not going to know everything just yet. Therefore, I think that statements like the ones Exapno Mapcase first quoted are a little Pollyanna-ish, that’s all. Completely agree with the gist of Exapno’s quoted report—this isn’t Chernobyl, things are under control—I’m just taking issue with what I perceive as an incredibly optimistic tone.
As far as wowellness’s post about spent rods leading to disaster as their cooling pool evaporates, I first thought the person is thinking about something like the Kyshtym disaster in 1957. The wiki for the Spent Fuel Pool (SFP). Here are some .pdfs discussing reports analyzing the risks of spent fuel at nuclear power generating stations in the U.S. Among the hazards analyzed were a terrorists or accidents draining away the cooling water within the SFP. I could totally be misreading this, but for some reason, Boiling Water Reactors, like the one at Fukushima, seem to have their SFP’s above grade; Pressurized Water Reactors, conversely, seem to have their SFP’s below grade. I don’t know, but it seems a reasonable inference the SFP at Fukushima may be above grade, and above grade, it might have lost some integrity from the earthquake. Or it may be just fine, I can’t find any info either way. Removing the fuel and fixing a SFP can be a rather involved process, see this press release here for some detail as to the cleanup activities required.
A roundtable discussion on the safety of SFPs may be found here. NUREG-1738, Technical Study of Spent Fuel Pool Accident Risk at Decommissioning Nuclear Power Plants is a lengthy report discussing those all of those risks, among others. I can’t find a downloadable .pdf, but I imagine it would answer many questions about this topic. A .pdf of a letter stating the NUREG-1738 overstates the risk from SFPs may be found here. Pages 44-50 of, Safety and security of commercial spent nuclear fuel storage: public report By National Research Council, Committee on the Safety and Security of Commercial Spent Nuclear Fuel Storage. (On Google Books) goes into more detail. I’d quote it, but for its size. A site selling simulator software for reactor plant personnel dealing with SFPs has a helpful quiz on the hazards of SFP loss of coolant. Their “correct” answers mention a few days to boil off the water, and consequences of doing so including: a fire, prompt deaths in the 10s, and cancer deaths in the 10^5 range, primarily due to dispersal of Cs-137. Keeping the spent fuel covered with water avoids all of these problems, of course.
Thanks for the Spectrum link, Exapno. I agree that the situation is being addressed vigorously, as it needs to be. I also agree with your comments doomsday scenarios and how they get in the way of understanding what’s going on. Has robby, or other NukE’s chimed in on this topic yet? Be interested to read what they have to say.
Latest press release from TEPCO, Tokyo Electric Power Company, on the status of their Fukushima power station. Highlights:
Which I’m interpreting to mean that the SFP has water in it, therefore the pool has sufficient integrity, and the issue is restarting cooling of that water. That’s a relief. Given the proximity of the SFP to the reactor, and looking at the video of the explosion, that’s a pleasant surprise.
I am not a nuclear engineer. I was an electrical engineer, though, so technical stuff doesn’t completely flow over my head. I also support nuclear power as the lessor of a number of evils.
However, my impression, watching the news conference my Tepco, is that I would never, ever believe anything they said.
There have been a variety of reports, with very few details, that some of the fuel rods at one, possibly more, of the reactors had been fully exposed. Apparently more water was then pumped in. The problem seems to be that the pressure inside the containment dome makes it difficult to force the water in.
I’m posting this at close to noon EDT. I’ve been searching for recent articles on Google News but I’ve been finding that even the ones that are listed as having been posted only a few minutes ago actually have datelines that are hours old.
The composite scenario that I’m taking away is that it is likely the fuel rods will melt but highly unlikely that any breach of the containment dome will occur. Except that a controlled breach to vent hydrogen gas may be used. Presumably that would be at the top rather than the bottom. The fuel rods melt down, in both senses.
It continues to be a very bad situation, but not a worse case one.
Sadly, this. My relatives have already phoned me (“that scientist guy”) leading off with “See! This is why nuclear will never be a good idea!” Even though no one has died, and a handful have received light dentist’s-visit levels of exposure, the hysteria surrounding the mere mention of the word “radiation” defies rational discussion.
“Mom…even though this reactor was 40 years old, is an obsolete design, and was hit with an earthquake 10 times more powerful than it was rated for, and even if it melts down, it will all likely be contained.”
“But is it ok for me to go outside? Should I plant a garden this year?”
I agree, but that’s assuming that the earthquake hasn’t damaged the containment systems, and that aftershocks in the 8.0 range don’t cause more damage. This seems unlikely, but the magnitude of the quake has already pushed us into the realm of the unlikely.
Japan has 54 nuclear power plants, 51 of which came through just fine. Only eight others are offline, mostly due to problems with the electrical grid rather than the nuclear plant itself.
But half of their electricity production comes from coal-fired plants, and many more of those plants have been affected by the quake. This article, on the impact the disaster will have on worldwide coal prices, has the following quote from an analyst:
I would suspect that their natural gas infrastructure was probably devastated, and their ability to store and deliver gasoline and other oil was probably also dealt a blow. When you look at it in that context, the nuclear plants actually held up better than any of the other energy sources.
The concern is that the wet well torus on reactor 2 is now breached, since its pressure dropped from 3 bar to atmospheric with something of a bang. The torus is outside the primary concrete “lightbulb” housing the reactor vessel, although it is still inside the concrete structure of the reactor building. The top of the reactor building (the bit with the steel frames) is the bit that has blown off on reactors 1 and 3.
If reactor 2 suffers a full meltdown, there is pathway around the primary containment through the torus for radioactive material to escape. I don’t know if the torus can be sealed off from the primary containment, or whether the concrete surrounding the torus forms any sort of containment itself.
So, has the reactor been breached? After that you have the containment vessel. You are suggesting that is breached. Not sure how that would happen. Hydrogen explosion crack it?
I confess amazement in the Three Mile Island disaster that no one seem able to look at the damn room to assess what was happening. I would have hoped after that every reactor in the world took measures to be better. A camera in the room would seem to have done wonders at TMI.
Re reactor 2: The reactor vessel has not been breached. The primary concrete containment has not been breached. The steel water-filled torus may have been breached since it suffered an abrupt loss of pressure, but there appear to be vents passing through the primary concrete containment to the steel torus and the torus is outside the primary containment.
What that all adds up to, I don’t know. There’s a whole bunch of different circulating systems for passing water through the reactor vessel, and presumably it’s through one of these systems that seawater is being injected. There’s no information as to whether any pumping circulation has been achieved or if they’re just forcing in water and venting steam. The torus is supposed to act as a heat dump whereby steam in the primary containment can be condensed by contact with the torus water. You can only do that for so long before the torus water gets too hot, and then pressure builds and you have to vent. 3 atmospheres in the torus is nowhere near high enough pressure to worry about though, so who knows what happened.
The amount of technical information coming out of this situation is pitiful and journalists seem utterly disinclined to seek it out. I’ve no idea why a whole bunch of General Electric people or technical guys operating the same kind of reactor (there are still other Mark 1 BWRs about) aren’t being interviewed.
I agree with you, matt, there’s been a dearth of good technical analysis concerning this plant and that you’d think GE would be chomping at the bit to provide it.
Latest AP story is that 140,000 people are sheltering in place to avoid radiation.
Sounds like the SFP may not be all right after all. I really hope the spent fuel isn’t exposed and burning right now… Still not Chernobyl, but I don’t think this stays at a 4 on the oft-mentioned scale.
Wiki is not to be believed. Any idiot can edit it at any time. How much you want to bet much of the info on there is by mediocrities (or worse) who haven’t the vaguest idea what they are talking about? Even if an expert (without an agenda) is monitoring it, accurate info can’t come fast enough and be posted, as long as the expert is busy correcting or deleting misinformation.
There’s been a lot of what beowulff called “rah-rah” misinformation to compete with the panicmongering. It’s worth noting that on 3/13 this was posted:
…and today, two days later (3/15), the headline on CNN says “New Blast at Nuclear Plant.”
It’s still difficult to determine through the popular media what’s actually happened and what’s still happening. If my own sifting through various sources is accurate (who knows?), the plant has suffered 3 explosions and a fire in 4 days; I thought I read somewhere that two of the hydrogen explosions breached reactor containment* buildings* but not containment vessels themselves, but I can’t cite that.
There’s also this issue with the spent fuel pool.
Company propaganda should be taken with a grain of salt, especially by people who doubt antinuclear sources because they assume they’re biased – like the company wouldn’t be?
It’s a little too early for definite pronouncements of any kind, I think. We’ll learn more soon.