This post is obsolete. It was a developing live-blog of events and is no longer accurate.
A compilation from various sources:
- Massive (8.9) earthquake struck off Japan coast
- 11 reactors automatically shut down [1]
- Emergency declared at Fukushima Daiichi NPP after failure of reactor cooling systems [1]
- Specifically, backup generators failed [2]
- No AC power at all at Fukushima Daiichi units #1,2,3 [7]; running on batteries [12]
- "status of reactor water coolant injection could not be confirmed" for units #1,2 [8]
- Nuclear agency says "...plant workers are currently scrambling to restore cooling water supply... no prospect for an immediate success" [4]
- Evacuation order issued [4] at a 3 km radius [5] [11]
- Separately, emergency core coolant system activated [3] in Fukushima Daini unit #1 following suspected coolant leak [9]
- Separately, fire in turbine hall at Onagawa NPP [6]
- Separately, unspecified coolant leak at another Onagawa unit [6]
- No radiological releases recorded [all sources]
The NPP has 10 reactors: Fukushima Daiichi (Fukushima 1) has six units, and Fukushima Daini (Fukushima 2) has four. According to TEPCO, Fukushima Daiichi #4,5,6 were in an outage, and the other seven were shut down in the earthquake [11].
[1] [Guardian] Japan declares 'nuclear emergency' after quake
[2] [NEI Magazine] Japan initiates emergency protocol after earthquake
[3] [AFP/Kyodo] Fire breaks out at Japanese nuclear plant: Kyodo
[4] [AP] Japan to evacuate residents near nuke plant
[5] [Reuters] Japan trying to fix nuclear plant cooling problem
[6] [Washington Post] Japan issues emergency at nuke plant; no leak
[10] [IAEA] Japan: Nuclear Power Reactors - Alphabetic
[11] [TEPCO] Impact to TEPCO's Facilities due to Miyagiken-Oki Earthquake (as of 10PM)
[12] [Bloomberg] Japan Orders Evacuation From Near Nuclear Plant After Quake
The Fukushima incident appears to be the most severe, with insufficient backup power to remove decay heat. Those units are older BWRs and were not designed as fully for beyond design basis accidents. The newer ABWRs have improved in vessel melt arrest and retention and would not pose a safety risk even in the most severe quake. Though BWRs do have the advantage of lower power density cores and much more in vessel water volumes, compared to PWR.
ReplyDeleteIf no significant radioactivity is released then we have a good case against the fear mongering that quakes could lead to severe nuclear safety disasters.