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Nuclear Experts Explain Worst-Case Scenario at Fukushima Power Plant
- nazgulnarsil 16y ago"we're in a land where probability says we shouldn't be." You, sir, need better advisors.
- Ratfish 16y agoGo easy... "it was the earthquake and tsunami." they didn't go together in any of the scenarios they ran.
- makmanalp 16y agoAre you shitting me? This is Japan. Earthquakes happen very often and it's well known even by common people that they are closely followed by tsunamis. The fact that they didn't go together in any of the scenarios is mindblowing.
- barrkel 16y agoFairly sure Ratfish was being sarcastic.
- user9756 16y agoYour comment broke my sarcasm detector. According to Wikipedia: http://en.wikipedia.org/wiki/Tsunami#Generation_mechanisms http://en.wikipedia.org/wiki/Tsunami#Generation_mechanisms "The principal generation mechanism (or cause) of a tsunami is the displacement of a substantial volume of water or perturbation of the sea. This displacement of water is usually attributed to either earthquakes, landslides, volcanic eruptions, or more rarely by meteorites and nuclear tests." Like the previous gentleman stated. Better advisers? EDIT: spelling
- wtn 16y agoYes, this part of the article was incredibly hilarious.
- starpilot 16y agoTo be fair, the plant has operated through thirteen [1] previous earthquakes in Japan since its first reactor reached criticality in 1970 [2]. [1] http://en.wikipedia.org/wiki/List_of_earthquakes_in_Japan http://en.wikipedia.org/wiki/List_of_earthquakes_in_Japan [2] http://en.wikipedia.org/wiki/Fukushima_I_Nuclear_Power_Plant#Reactors http://en.wikipedia.org/wiki/Fukushima_I_Nuclear_Power_Plant...
- mbreese 16y agoThe earthquake and tsunami weren't the coupled failures they were talking about. It was the loss of external power and backup generators. This is what they didn't expect, because it is hard to predict the probability of an event big enough to trigger these two things failing at the same time.
- moe 16y agoYes, it's indeed hard to predict an earthquake to take out the external power and the subsequent tsunami to take out the backup generators on a coastline facility. (Note: This was sarcasm)
- mbreese 16y agoHow big of a tsunami was required? How big of a earthquake would be required to generate such a wave? How much water would be needed to reach the facility? How much to damage it? What about damaging backups? Sarcasm aside, it is easy to predict that the facility would be at risk for an earthquake/tsunami combo. The hard part is to predict how much of one to prepapre for. Remember, even in this neck of the woods, the was a quake of historic proportions.
- superkarn 16y agoIsn't that partly why they have a secondary backup?
- btmorex 16y agoIt's interesting. I've been reading the science subreddit and a lot of people are holding this up and some kind of engineering triumph, but to me it's an absolute engineering failure. Even if nothing bad happens from this point forward, two reactors were almost certainly destroyed and they'll have to sit dormant for a long while before they can be properly cleaned up. And as far as I can tell, there's still a very real risk of meltdown/containment vessel breach. From my perspective, the root cause of what happened is that no one anticipated an event that would simultaneously cause failures in multiple systems (power loss, and destroy probably multiple redundant generators). It's easy to say after the fact that of course someone should have thought about that, in your words they should have had "better advisors", but I'm not sure how useful it is. All nuclear accidents that I'm familiar with were unanticipated. Can anyone really argue that they all just had bad advisors or engineers? To me, this is the real argument against nuclear power and I say this as someone who still thinks that overall it's a good idea. How can we say something is truly safe when the accidents that did happen were not anticipated?
- wtallis 16y agoI think it's too soon to say that this failure mode was never considered or even conceived of in the contingency planning for the power plant. If you have a source that says otherwise, please provide a link. Keep in mind that this is currently estimated to be the biggest earthquake in the recorded history of Japan. It's completely unreasonable to expect stuff to totally not break when the big one hits. If some reactors are damaged beyond repair, that's understandable, as long as the radiation is contained well enough to keep the public safe. After all, good safety plans will always be willing to sacrifice expensive infrastructure in order to save lives.
- erikpukinskis 16y agoUsing "biggest in recorded history" as an approximation for "biggest possible" seems weak to me. Proper engineering will look at the numbers and account for events outside of the historically observed range, but within the probability distribution. The "biggest event we see in 1,000,000 simulations of the lifetime of the plant" is likely much larger than the "biggest we've seen in history." Which isn't to say that it was bad engineering. Just that this being the biggest quake in history is not an excuse.
- blue1 16y agoIn other words, it's a magnificent example of Black Swan. Nassim Taleb will be happy.
- squidsoup 16y agoBuilding a nuclear power plant on the coastline of a subduction zone in a country with a long history of earthquakes and tsunamis does seem like a questionable idea.
- JonoW 16y agoYeah I don't understand why these plants weren't built on the West coast, and why they weren't built on higher ground to mitigate against tsunamis.
- cstross 16y agoYou can't build reactors on high ground because they need a very high coolant flow. The (elderly) Fukushima BWRs pumped 480Mw into the grid while they were running -- but that's at the far end of a lossy thermodynamic chain (steam is used to spin turbines which drive dynamos); the thermal power output is probably something like three times that. So you need a heat sink into which you can continuously dump about 1.5Gw of heat. Water fits the bill, but you need a lot of it -- either a big river, or an ocean. Which is why civil nuclear reactors are almost always built close to the coastline.
- superkarn 16y agoIs it feasible/economical to have a secondary power plant to convert all that heat into electricity?
- cstross 16y agoNot unless you repeal the second law of thermodynamics -- the 1.5Gw of heat was already used to generate 0.5Gw of electricity. In general, no thermal power plant can convert much more than about 40% of the input heat into useful work. See also: https://secure.wikimedia.org/wikipedia/en/wiki/Rankine_cycle https://secure.wikimedia.org/wikipedia/en/wiki/Rankine_cycle
- deleted 16y ago[deleted]
- sanxiyn 16y agoThings are moving fast. TEPCO(Tokyo Electric Power Company) reported that they have restored AC power to all units. http://www.tepco.co.jp/en/press/corp-com/release/11031302-e.html http://www.tepco.co.jp/en/press/corp-com/release/11031302-e....
- gommm 16y agoYou were linking to Fukushima Daini and not Daiichi http://www.tepco.co.jp/en/press/corp-com/release/11031305-e.html http://www.tepco.co.jp/en/press/corp-com/release/11031305-e.... It doesn't mention that the AC power is restored
- lispm 16y agoNo, that is not the plant where the main problems are. They are talking about the Daiichi reactors here: http://www.tepco.co.jp/en/press/corp-com/release/11031305-e.html http://www.tepco.co.jp/en/press/corp-com/release/11031305-e....
- extension 16y agoIn the case of a meltdown, what exactly is the damage?
- user9756 16y agoEverything?
- adbge 16y agoIf a meltdown does occur, damage will depend on whether or not the reactor's containment structure holds. In the case that it does hold, the plant itself is FUBAR'd but, otherwise, there isn't significant cause for concern. This would be analogous to the Three Mile Island accident -- in which a partial meltdown occurred but was successfully contained. If the containment structure is breached, the resulting fallout will be comparable to that of the Chernobyl disaster which, like most Soviet reactors, had no containment structure whatsoever. Wikipedia has a good article on the effects of the Chernobyl disaster: http://en.wikipedia.org/wiki/Chernobyl_disaster_effects http://en.wikipedia.org/wiki/Chernobyl_disaster_effects
- wtallis 16y agoChernobyl was worse than just a meltdown. The graphite moderator caught fire and helped carry fallout into the atmosphere. This would not likely happen at Fukushima, as it is water-moderated, nor would the uranium fuel be able to catch fire as happened at Windscale, because modern reactors use uranium oxide instead of metallic uranium. In the event that containment is lost, there will still be contamination, but it probably couldn't be spread anywhere near as widely as the fallout from Chernobyl.
- Ratfish 16y agoAre the containment domes intact in Japan? Edit: found this on IAEA site: "Containment remains intact at Fukushima Daiichi Units 1, 2 and 3". It doesn't even mention the 4th, but does say the explosion occurred outside unit 1s primary containment dome. What does that mean? It's outer shield is wrecked?
- 16y ago
- ck2 16y agoSerious suggestion for our Japanese friends http://nukalert.com http://nukalert.com added: looks like they have a page for Japan http://nukalert.jp http://nukalert.jp
- nicolas_t 16y agoAs someone who lives in Shanghai, 1850km away, I wonder if I should go a bit further away as a precaution? During the Chernobyl accident the nuclear clouds reached up to 2500 kms away from Chernobyl...
- wtn 16y agoYou should probably move away to avoid the air pollution in Shanghai.
- davidw 16y agoDepends on the prevailing winds, which I think generally go from west to east in the northern hemisphere, but no idea how things actually work in that area.
- masklinn 16y agoDominant winds go to the Pacific, even if there is meltdown and containment breach, California is more at risk than China is.
- nostrademons 16y agoAs someone who lives in California, 8800km away, I wonder if I should go a bit further away as a precaution...? ;-)
- codingthewheel 16y agoYou should probably move away to avoid the air pollution in California.
- Entlin 16y agoWhy aren't all reactors mandated to keep a huge tank of emergency water at some height, so that you only need to open some bulkhead and gravity will ensure that the reactor gets cooled during the 7 or so days it takes to cool down. No batteries, no diesel, no offsite power needed.
- patrickgzill 16y agoThis is actually the case for the design of some of the newer ALWR style reactors. There are 3 or more holes at different heights, designed so that the most water flows in the early hours of cooling when the most cooling is needed, then tapering off to 2 then 1 holes with the water flow lessening over time.
- deleted 16y ago[deleted]
- rabidsnail 16y agoLesson: Don't build systems whose steady state is a catastrophe.