4 ms·

The scenario is slightly more complicated: power loss, loss of backup power sources and not being able to solve either of those two issues before the secondary

The scenario is slightly more complicated: power loss, loss of backup power sources and not being able to solve either of those two issues before the secondary backup power source, the batteries, ran out. We're dealing with what is almost the worst case scenario the reactors are prepared for. That the reactors should be considered lost in such a situation is by design. How is it an engineering failure if everything operates as it was designed to? And as far as I can tell, there's still a very real risk of meltdown/containment vessel breach There is, but that is the worst scenario that the reactor is prepared for: that the fuel rods melt through the bottom of the containment vessel. There is secondary containment with a huge heat sink down there. Damage will still be contained. But as they are now pumping seawater into the reactor, we won't get to test that bit of engineering.

lispm 16y ago
I'm not supporting a technology which has these kinds of worst case scenarios happening.
- Confusion 16y ago
  The worst case scenario of driving a car is meeting a drunken or sleepy driver and dying in the resulting crash. This happens thousands of times every year and seems to be an acceptable risk. I don't understand why a technology with large economic damage as the worst case scenario would be less acceptable.
  - lispm 16y ago
    There are scenarios, where a nuclear accident has a damage that makes living in that area impossible for a long time. Then you don't even have a choice whether you want to drive or not. The people of Prypjat had to leave and the region there is uninhabitable for the next 300 years. There are very few car crashes in that area.
- adrianN 16y ago
  Why do so many people only care about the worst case scenario? You should always consider the expected outcomes when arguing for or against a technology. Sure, in the worst case a nuclear reactor can kill thousands and make large areas no longer habitable, but this event has only a tiny probability. On the other hand conventional fossil fuel plants don't have such a dramatic worst case but they produce a constant stream of greenhouse gases and other toxic fumes. How many people died because of smog? How much land will become unusable due to global warming? It's the expected harm we should be worried about, not the worst case scenarios.
  - jeza 16y ago
    This scenario you mention about global warming is still an assumption that relies at least somewhat on probabilities. Many scientists believe global warming from CO2 emissions is highly likely, while others don't (they tend to be labeled as skeptics). Though there are too many variables that we as humans don't fully understand. So even if it is true and it makes some land unusable, it may well make other areas such as existing desert usable. So I don't really know that this makes a tiny probability of a nuclear accident all that acceptable. That said, I'm not against nuclear energy, but the probability of accidents needs to be next to nothing. Build enough reactors near fault lines and the probability of one of them receiving an 8.9 earthquake would surely approach certainty.
  - lispm 16y ago
    This does not help the people of the Ukraine. It happened there and it affected millions of people. The nuclear industry has a couple of worst case scenarios which are extremely frightening. From the sabotage of a nuclear facility to large scale accidents like in Japan. I know not many industries which have that. I remember years ago, the air here in Germany was very dirty. Then there were tighter regulations and improved technology. Now the air is much better, still not good enough in some areas - but the difference is huge. When you have an exposure of radiation here, then you can't clean it up. The particles are everywhere. Tighter regulations will not bring improvements. The damage is done. Possibly for decades. People here accept neither coal plants nor nuclear technology. They demand that most of the investment in future energy technology goes into renewables. This will not bring improvement in a day, but after a few decades a multitude of actions will make dirty and/or energy production phased out. This scenario is planned here for Germany in 2050. Fourty years from now. Under the impression of the Japanese problems with their nuclear power plants, people are willing to accelerate that. This means that for years there will be investments in new technologies, there will be implementations of those that not everybody will like, but Germany is a country with engineering tradition and this is a challenge people like.
- wtallis 16y ago
  I'm having trouble understanding what you mean by that. Do you mean that you are opposed to the use of technology if it's safety systems are ever fully put to the test, or are you saying that having the reactor core melt and puddle at the bottom of the room where it will eventually cool off and harden is just too catastrophically dangerous? Either way, it's absurd. Shit happens. In this case, a big earthquake and tsunami. The fact that a safety system has to be used does not reflect poorly on the safety system. The earthquake has already killed far more people and caused more damage than even Chernobyl, and the tsunami has certainly caused more dangerous chemical contamination than whatever radiation may be released from Fukushima.
  - mrleinad 16y ago
    "There is secondary containment with a huge heat sink down there" Can I ask an uncomfortable question? If that secondary containment is enough to hold the molten core, why didn't they build the first containment that way? Oh.. right..
    - z92 16y ago
      Think about the secondary containment as the graveyard. The primary containment allows production of energy and the system to actually run, while the secondary doesn't. It's hole in the ground to catch the collapsed thing.
    - joesb 16y ago
      If the black box material is enough to survive a plane crash, why didn't they they build the whole plane with blackbox material?
    - adrianN 16y ago
      For the same reason your server has a UPS although it also has regular power.
  - lispm 16y ago
    After an earth quake people can move back into the area. Living in an area where a nuclear accident happened may not possible for many years. If there is radioactivity released, then we are talking about large scale consequences. Tokio is just 240km away from Fukushima and there are living 30 Million people. Imagine if they have to leave the city behind. Chernobyl had a certain type of scenario with radioactive particles released of a huge area in Europe. This has still effects. For the economy of the Ukraine in means that the have a region which can 't be developed, they have to pay for the maintenance of the broken reactor for decades and for example agriculture in that area is not really possible. Nobody outside the Ukraine will buy vegetable from them. Check out the coal power plants. They had problems during the earth quake, but they fail and that's mostly it. The nuclear reactors are full losses costing billions and need and extremely dangerous type of further maintenance. I don't know many people who would want to work on Fukushima later. Who should clean up the site??? Which humans do we want to give these tasks??? In Chernobyl there was a lot of radiation released. Workers had a years of typical dose in a few minutes. I don't believe for a second that workers in Fukushima will not exposed to radiation. Even the US Navy pulls a ship away from the site, because it measured radiation in 160km distance.
- PakG1 16y ago
  Good engineering prepares for worst-case scenarios. Fact of life and the only reason why good engineering is trustworthy.

lispm 16y ago

I'm not supporting a technology which has these kinds of worst case scenarios happening.

Confusion 16y ago
The worst case scenario of driving a car is meeting a drunken or sleepy driver and dying in the resulting crash. This happens thousands of times every year and seems to be an acceptable risk. I don't understand why a technology with large economic damage as the worst case scenario would be less acceptable.
- lispm 16y ago
  There are scenarios, where a nuclear accident has a damage that makes living in that area impossible for a long time. Then you don't even have a choice whether you want to drive or not. The people of Prypjat had to leave and the region there is uninhabitable for the next 300 years. There are very few car crashes in that area.
adrianN 16y ago
Why do so many people only care about the worst case scenario? You should always consider the expected outcomes when arguing for or against a technology. Sure, in the worst case a nuclear reactor can kill thousands and make large areas no longer habitable, but this event has only a tiny probability. On the other hand conventional fossil fuel plants don't have such a dramatic worst case but they produce a constant stream of greenhouse gases and other toxic fumes. How many people died because of smog? How much land will become unusable due to global warming? It's the expected harm we should be worried about, not the worst case scenarios.
- jeza 16y ago
  This scenario you mention about global warming is still an assumption that relies at least somewhat on probabilities. Many scientists believe global warming from CO2 emissions is highly likely, while others don't (they tend to be labeled as skeptics). Though there are too many variables that we as humans don't fully understand. So even if it is true and it makes some land unusable, it may well make other areas such as existing desert usable. So I don't really know that this makes a tiny probability of a nuclear accident all that acceptable. That said, I'm not against nuclear energy, but the probability of accidents needs to be next to nothing. Build enough reactors near fault lines and the probability of one of them receiving an 8.9 earthquake would surely approach certainty.
- lispm 16y ago
  This does not help the people of the Ukraine. It happened there and it affected millions of people. The nuclear industry has a couple of worst case scenarios which are extremely frightening. From the sabotage of a nuclear facility to large scale accidents like in Japan. I know not many industries which have that. I remember years ago, the air here in Germany was very dirty. Then there were tighter regulations and improved technology. Now the air is much better, still not good enough in some areas - but the difference is huge. When you have an exposure of radiation here, then you can't clean it up. The particles are everywhere. Tighter regulations will not bring improvements. The damage is done. Possibly for decades. People here accept neither coal plants nor nuclear technology. They demand that most of the investment in future energy technology goes into renewables. This will not bring improvement in a day, but after a few decades a multitude of actions will make dirty and/or energy production phased out. This scenario is planned here for Germany in 2050. Fourty years from now. Under the impression of the Japanese problems with their nuclear power plants, people are willing to accelerate that. This means that for years there will be investments in new technologies, there will be implementations of those that not everybody will like, but Germany is a country with engineering tradition and this is a challenge people like.
wtallis 16y ago
I'm having trouble understanding what you mean by that. Do you mean that you are opposed to the use of technology if it's safety systems are ever fully put to the test, or are you saying that having the reactor core melt and puddle at the bottom of the room where it will eventually cool off and harden is just too catastrophically dangerous? Either way, it's absurd. Shit happens. In this case, a big earthquake and tsunami. The fact that a safety system has to be used does not reflect poorly on the safety system. The earthquake has already killed far more people and caused more damage than even Chernobyl, and the tsunami has certainly caused more dangerous chemical contamination than whatever radiation may be released from Fukushima.
- mrleinad 16y ago
  "There is secondary containment with a huge heat sink down there" Can I ask an uncomfortable question? If that secondary containment is enough to hold the molten core, why didn't they build the first containment that way? Oh.. right..
  - z92 16y ago
    Think about the secondary containment as the graveyard. The primary containment allows production of energy and the system to actually run, while the secondary doesn't. It's hole in the ground to catch the collapsed thing.
  - joesb 16y ago
    If the black box material is enough to survive a plane crash, why didn't they they build the whole plane with blackbox material?
  - adrianN 16y ago
    For the same reason your server has a UPS although it also has regular power.
- lispm 16y ago
  After an earth quake people can move back into the area. Living in an area where a nuclear accident happened may not possible for many years. If there is radioactivity released, then we are talking about large scale consequences. Tokio is just 240km away from Fukushima and there are living 30 Million people. Imagine if they have to leave the city behind. Chernobyl had a certain type of scenario with radioactive particles released of a huge area in Europe. This has still effects. For the economy of the Ukraine in means that the have a region which can 't be developed, they have to pay for the maintenance of the broken reactor for decades and for example agriculture in that area is not really possible. Nobody outside the Ukraine will buy vegetable from them. Check out the coal power plants. They had problems during the earth quake, but they fail and that's mostly it. The nuclear reactors are full losses costing billions and need and extremely dangerous type of further maintenance. I don't know many people who would want to work on Fukushima later. Who should clean up the site??? Which humans do we want to give these tasks??? In Chernobyl there was a lot of radiation released. Workers had a years of typical dose in a few minutes. I don't believe for a second that workers in Fukushima will not exposed to radiation. Even the US Navy pulls a ship away from the site, because it measured radiation in 160km distance.
PakG1 16y ago
Good engineering prepares for worst-case scenarios. Fact of life and the only reason why good engineering is trustworthy.