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http://twitter.com/#!/martyn_williams/status/46537158915391488 http://twitter.com/#!/martyn_williams/status/465371589153914... The reactor DID NOT explode. HN

http://twitter.com/#!/martyn_williams/status/46537158915391488 http://twitter.com/#!/martyn_williams/status/465371589153914... The reactor DID NOT explode. HN is becoming a bit sensationalist today. Edit: http://en.wikipedia.org/wiki/Boiling_Water_Reactor_Safety_Systems#Containment_system http://en.wikipedia.org/wiki/Boiling_Water_Reactor_Safety_Sy... Basically, this bit: The reactor building (the shield wall/missile shield) is also made of steel-reinforced, pre-stressed concrete 0.3 m to 1 m (1–3 feet) thick. The concrete surrounding the building is now gone (due to excess pressure). Second edit: [6:54 a.m. ET, 8:54 p.m. Tokyo] The explosion at Japan's Fukushima nuclear plant was not caused by the nuclear reactor but by "water vapor that was part of the cooling process," Chief Cabinet Secretary Yukio Edano said Saturday. He said no harmful gases had been emitted by the explosion. [6:44 a.m. ET, 8:44 p.m. Tokyo] Japanese Prime Minister Naoto Kan confirms that the evacuation area around the Fukushima Daiichi nuclear plant has been increased to 20 kilometers. But no one has been harmed by radiation, he says. Third edit (from the BBC): 1218: It seems clear now from Mr Edano's comments that the nuclear plant building that was blown apart earlier did house a reactor, but the reactor was protected by its metal casing. 1216: Government spokesman Yukio Edano says the pressure as well as the radiation at the Fukushima-Daiichi nuclear plant has fallen following this afternoon's explosion. So the "explosion" has actually helped the situation. Fourth edit: Looking like Sendai just got hit with another earthquake. I hope that hasn't caused any more damage to the reactor. http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc00020m9.php http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/us... Fifth edit: From http://twitter.com/#!/norishikata http://twitter.com/#!/norishikata "Blast was caused by accumulated hydrogen combined with oxygen in the space between container and outer structure. No damage to container." "Trend of μ Sv/h of Unit 1 this afternoon. 1,015(at 15:29), blast (15:36), 860(15:40), 70.5 (18:58). After blast, radioactive level lowered." "TEPCO's efforts to depressurize the container was successful. Additional measures are now taken tonight using sea water and boric acid." Things are looking up.

jensnockert 16y ago
While damage to internal containment structures are possible, the building is likely to be resistant to these kinds of explosions. A (what I guess) is a similar explosion happened in the reactor building in TMI, and the risk of an explosion such as this seems to be well known. The reactor building was probably prepared to absorb the explosion away from the containment structures, making it look much worse than it is.
- foobarbazetc 16y ago
  I think you're right. I'm not sure on how PWR vs BWR plays out in this case though, but it definitely seems like they knew this explosion would happen. It looked very "controlled", even if it seemed like there was a lot of vapour and debris on video.
  - jensnockert 16y ago
    Yes, PWR vs. BWR is definatly an issue when comparing the two events.
- jensnockert 16y ago
  Someone has compiled information about the structure of the reactor in question. http://uvdiv.blogspot.com/2011/03/some-links-on-fukushima-daiichi-1.html http://uvdiv.blogspot.com/2011/03/some-links-on-fukushima-da...
uvdiv 16y ago
"We've confirmed that the reactor container was not damaged. The explosion didn't occur inside the reactor container. As such there was no large amount of radiation leakage outside," [Japan Chief Cabinet Minister Yukio Edano] said. "At this point, there has been no major change to the level of radiation leakage outside (from before and after the explosion), so we'd like everyone to respond calmly," Edano said." http://www.reuters.com/article/2011/03/12/japan-quake-reactor-idAFTKZ00680620110312 http://www.reuters.com/article/2011/03/12/japan-quake-reacto... Now they are going to flood the reactor container with seawater.
- foobarbazetc 16y ago
  The reason for the building blowing out: "Edano said due to the falling level of cooling water, hydrogen was generated and that leaked to the space between the building and the container and the explosion happened when the hydrogen mixed with oxygen there." It looks like they're about to use this: Low Pressure Coolant Injection System (LPCI) Then this: Standby Liquid Control System (SLCS) http://en.wikipedia.org/wiki/Boiling_Water_Reactor_Safety_Systems http://en.wikipedia.org/wiki/Boiling_Water_Reactor_Safety_Sy... Looks like they've given up saving the reactor.

jensnockert 16y ago

While damage to internal containment structures are possible, the building is likely to be resistant to these kinds of explosions. A (what I guess) is a similar explosion happened in the reactor building in TMI, and the risk of an explosion such as this seems to be well known. The reactor building was probably prepared to absorb the explosion away from the containment structures, making it look much worse than it is.

foobarbazetc 16y ago
I think you're right. I'm not sure on how PWR vs BWR plays out in this case though, but it definitely seems like they knew this explosion would happen. It looked very "controlled", even if it seemed like there was a lot of vapour and debris on video.
- jensnockert 16y ago
  Yes, PWR vs. BWR is definatly an issue when comparing the two events.
jensnockert 16y ago
Someone has compiled information about the structure of the reactor in question. http://uvdiv.blogspot.com/2011/03/some-links-on-fukushima-daiichi-1.html http://uvdiv.blogspot.com/2011/03/some-links-on-fukushima-da...

uvdiv 16y ago

"We've confirmed that the reactor container was not damaged. The explosion didn't occur inside the reactor container. As such there was no large amount of radiation leakage outside," [Japan Chief Cabinet Minister Yukio Edano] said. "At this point, there has been no major change to the level of radiation leakage outside (from before and after the explosion), so we'd like everyone to respond calmly," Edano said." http://www.reuters.com/article/2011/03/12/japan-quake-reactor-idAFTKZ00680620110312 http://www.reuters.com/article/2011/03/12/japan-quake-reacto... Now they are going to flood the reactor container with seawater.

foobarbazetc 16y ago
The reason for the building blowing out: "Edano said due to the falling level of cooling water, hydrogen was generated and that leaked to the space between the building and the container and the explosion happened when the hydrogen mixed with oxygen there." It looks like they're about to use this: Low Pressure Coolant Injection System (LPCI) Then this: Standby Liquid Control System (SLCS) http://en.wikipedia.org/wiki/Boiling_Water_Reactor_Safety_Systems http://en.wikipedia.org/wiki/Boiling_Water_Reactor_Safety_Sy... Looks like they've given up saving the reactor.