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"This is starting to look a lot like Chernobyl" Walt Patterson, an associate fellow with Chatham House, has told the BBC after seeing pictures of the explosion

by koski 16y ago

"This is starting to look a lot like Chernobyl" Walt Patterson, an associate fellow with Chatham House, has told the BBC after seeing pictures of the explosion at the Fukushima-Daiichi nuclear plant. "The nuclear agency says that they have detected caesium and iodine outside the unit, which certainly indicates fuel melting at the very least," he says. "Once you have melting fuel coming into contact with water, that would almost certainly be the cause of the explosion." (BBC) (EDIT) More from Walt Patterson of Chatham House. He says the presence of the radioactive caesium in the surrounding area does not pose a huge threat to public health in the immediate aftermath of the explosion. "What would be serious is if there was an explosion or fire that lifted this stuff high in the air, meaning it could get carried over a wide area."

wazoox 16y ago
This is quite different from Chernobyl, which didn't even have a proper confinement wall. It's unlikely that it can get as bad as Chernobyl was.
- JanezStupar 16y ago
  It seems that proper containment is gone in this case...
  - jessedhillon 16y ago
    It seems that what you saw was the building surrounding the reactor being blown up, not the containment vessel, according to news accounts. The containment referred to in this case is a vessel made of a feet-thick layer of concrete surrounding the reactor. This is the final defense if a fuel meltdown occurs: its job is to contain the burning fuel and prevent it from being exposed to the environment. [1] What the GP was referring to is that there was no such vessel at Chernobyl, which was a very old reactor design. Modern reactors are surrounded in such vessels. [2] [1] http://en.wikipedia.org/wiki/Containment_building http://en.wikipedia.org/wiki/Containment_building [2] Here's some information about the reactor design at Chernobyl: http://en.wikipedia.org/wiki/RBMK#Containment http://en.wikipedia.org/wiki/RBMK#Containment Another interesting read is the story of the Russian engineers who prevented an explosion at Chernobyl by diving into the pool of water beneath the reactor and opening the drainage valves: http://en.wikipedia.org/wiki/Chernobyl_disaster#Steam_explosion_risk http://en.wikipedia.org/wiki/Chernobyl_disaster#Steam_explos...
    - JanezStupar 16y ago
      I know the general layout of various types of nuclear reactors. But if the outer building which is supposed to contain everything else blows up - that's not exactly the best case is it?
      - vukk 16y ago
        "... that's not exactly the best case is it?" You could think about the outer building as keeping the rain out, and possibly aeroplanes to some extent. It is not the critical last defence against stuff happening in the reactor, the containment building is. You can bet that the japanese army is keeping any possible threats out of there.
        JanezStupar 16y ago
        I read somewhere that this design does not have a containment dome. So basically containment wise (in comparison to Chernobil) this reactor is a bit better that it uses reactor containment vessel, but it does not use containment dome. I also read that on TMI a similar hydrogen explosion occurred but it was contained by containment dome.
        neutronicus 16y ago
        It doesn't have a concrete containment dome. It's got a steel containment vessel surrounding the main reactor vessel, though.
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- runningdogx 16y ago
  Some reports[1] indicate radioactive iodine and cesium are being detected at monitoring stations. How could that happen if confinement hadn't failed? (fuel rods melting, containment failure of the reactor vessel and/or primary coolant loop, and the obvious lack of a containment building at this point) Based on the description of two-stage containment for BWRs at wikipedia[2], and the video, if that's the containment strategy at Fukushima, it seems the drywell containment structure blew up, since steam being vented into a pool of water shouldn't cause a visible breach. [1] http://e.nikkei.com/e/fr/tnks/Nni20110312D12JF520.htm http://e.nikkei.com/e/fr/tnks/Nni20110312D12JF520.htm [2] http://en.wikipedia.org/wiki/Containment_building#Boiling_water_reactors http://en.wikipedia.org/wiki/Containment_building#Boiling_wa...
- neutronicus 16y ago
  Chernobyl also was a _bona fide_ reactivity excursion - a nuclear-driven steam explosion literally blew the core apart and spewed radioactive particulates into the atmosphere. This is just built-up decay heat and chemical reactions.
rwmj 16y ago
Walt Patterson: http://www.waltpatterson.org/nuclearpower.htm http://www.waltpatterson.org/nuclearpower.htm http://www.chathamhouse.org.uk/about/directory/view/-/id/34/ http://www.chathamhouse.org.uk/about/directory/view/-/id/34/
desigooner 16y ago
BBC environment correspondent Roger Harrabin says local officials believe the release of radiation following the nuclear plant explosion is likely to be small. He adds that nuclear incidents aren't always as serious as they may sound or appear, and actually, in terms of loss of life and destruction, accidents at hydroelectric plants are far more dangerous.

by koski 16y ago

wazoox 16y ago

This is quite different from Chernobyl, which didn't even have a proper confinement wall. It's unlikely that it can get as bad as Chernobyl was.

JanezStupar 16y ago
It seems that proper containment is gone in this case...
- jessedhillon 16y ago
  It seems that what you saw was the building surrounding the reactor being blown up, not the containment vessel, according to news accounts. The containment referred to in this case is a vessel made of a feet-thick layer of concrete surrounding the reactor. This is the final defense if a fuel meltdown occurs: its job is to contain the burning fuel and prevent it from being exposed to the environment. [1] What the GP was referring to is that there was no such vessel at Chernobyl, which was a very old reactor design. Modern reactors are surrounded in such vessels. [2] [1] http://en.wikipedia.org/wiki/Containment_building http://en.wikipedia.org/wiki/Containment_building [2] Here's some information about the reactor design at Chernobyl: http://en.wikipedia.org/wiki/RBMK#Containment http://en.wikipedia.org/wiki/RBMK#Containment Another interesting read is the story of the Russian engineers who prevented an explosion at Chernobyl by diving into the pool of water beneath the reactor and opening the drainage valves: http://en.wikipedia.org/wiki/Chernobyl_disaster#Steam_explosion_risk http://en.wikipedia.org/wiki/Chernobyl_disaster#Steam_explos...
  - JanezStupar 16y ago
    I know the general layout of various types of nuclear reactors. But if the outer building which is supposed to contain everything else blows up - that's not exactly the best case is it?
    - vukk 16y ago
      "... that's not exactly the best case is it?" You could think about the outer building as keeping the rain out, and possibly aeroplanes to some extent. It is not the critical last defence against stuff happening in the reactor, the containment building is. You can bet that the japanese army is keeping any possible threats out of there.
      - JanezStupar 16y ago
        I read somewhere that this design does not have a containment dome. So basically containment wise (in comparison to Chernobil) this reactor is a bit better that it uses reactor containment vessel, but it does not use containment dome. I also read that on TMI a similar hydrogen explosion occurred but it was contained by containment dome.
        neutronicus 16y ago
        It doesn't have a concrete containment dome. It's got a steel containment vessel surrounding the main reactor vessel, though.
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runningdogx 16y ago
Some reports[1] indicate radioactive iodine and cesium are being detected at monitoring stations. How could that happen if confinement hadn't failed? (fuel rods melting, containment failure of the reactor vessel and/or primary coolant loop, and the obvious lack of a containment building at this point) Based on the description of two-stage containment for BWRs at wikipedia[2], and the video, if that's the containment strategy at Fukushima, it seems the drywell containment structure blew up, since steam being vented into a pool of water shouldn't cause a visible breach. [1] http://e.nikkei.com/e/fr/tnks/Nni20110312D12JF520.htm http://e.nikkei.com/e/fr/tnks/Nni20110312D12JF520.htm [2] http://en.wikipedia.org/wiki/Containment_building#Boiling_water_reactors http://en.wikipedia.org/wiki/Containment_building#Boiling_wa...
neutronicus 16y ago
Chernobyl also was a _bona fide_ reactivity excursion - a nuclear-driven steam explosion literally blew the core apart and spewed radioactive particulates into the atmosphere. This is just built-up decay heat and chemical reactions.

rwmj 16y ago

Walt Patterson: http://www.waltpatterson.org/nuclearpower.htm http://www.waltpatterson.org/nuclearpower.htm http://www.chathamhouse.org.uk/about/directory/view/-/id/34/ http://www.chathamhouse.org.uk/about/directory/view/-/id/34/

desigooner 16y ago

BBC environment correspondent Roger Harrabin says local officials believe the release of radiation following the nuclear plant explosion is likely to be small. He adds that nuclear incidents aren't always as serious as they may sound or appear, and actually, in terms of loss of life and destruction, accidents at hydroelectric plants are far more dangerous.