Credit: Digital Globe
Below is the full text of an IAEA update on Fukushima. Please note that the situation is, unfortunately, worsening by the minute. TEPCO is fighting heroically to stabilize the reactors, but they seem to be losing. I am not a reactor safety engineer, so I am uncomfortable offering too much commentary. But let me try to summarize what other people are saying:
For Unit 1, at least some of the core remains exposed and there is no word on the status of the spent fuel pond, which could ignite if water levels are not maintained.
When the IAEA released this document, Unit 2 was stable due to a temporary cooling measure. Now, the IAEA reports that Unit 2 “has experienced decreasing coolant levels in the reactor core.” This is the same failure mode that has afflicted Units 1 and 3.
Unit 3 has lost control of its valves, which were used to vent to reactors, leading to a dangerous pressure build-up (and no ability to pump in water).
I think we are now heading to three full core melts. Chances are, if the containment vessels are breached, the cores will melt through the bottom. There is a small possibility of a vent that would spew radiation. Bob Alvarez points to the possibility of a plutonium fire in the spent fuel ponds, which is a total wildcard. (See what the National Academies had to say about this possibility.)
The NRC has a 213 page document on all the things that can go wrong with a Boiling Water Reactor. It’s not fun reading.
Anyway, the IAEA report is after the jump.
INCIDENT AND EMERGENCY CENTRE
Subject: Status of the Fukushima Daiichi nuclear power plant
The Incident and Emergency Centre (IEC) is continuing to monitor the status of the nuclear power plants in Japan following the earthquake.
Based on information received by 05:40 UTC on March 14, 2011 the following update for the three reactor units at the Fukushima Daiichi nuclear power plant is provided:
The reactor is being maintained shutdown. There is currently neither off-site electrical power supply nor diesel generators providing power to Unit 1. Work continues to restore power to the plant. Currently mobile power generators are in use.
The water level in the reactor remains out of the measuring range, but at least 170 cm below the top of the core.
The injection of seawater and boron into the reactor vessel commenced at 11:20 UTC March 12 using a special piping configuration. Following this they commenced filling containment with sea water. At 16:10 UTC, 13 March the injection of Sea Water was interrupted due to low level in a sea water supply reservoir.
There is currently no updated information on the status of spent fuel and the structural integrity of primary containment.
The reactor is being maintained shutdown. There is currently neither off-site power supply nor diesel generators providing power to Unit 2. Work continues to restore power to the plant. Currently mobile power generators are in use. The reactor water level remained stable at approximately +380 cm above the top of the core. Cooling of the core is being maintained through reactor core isolation cooling. Containment is intact in Unit 2. Measures to lower containment pressure have been taken.
The reactor is being maintained shutdown. There is currently neither off-site power supply nor diesel generators providing power to Unit 3.
The reactor water level is between -150 to 200 cm below the top of the core. High pressure injection system failed at 20:10 UTC March 12 and other attempts of cooling failed.
From 00:08 UTC 13 March 2011 the injection of water and boron into the reactor vessel commenced. Levels continued to increase steadily for a certain time, but since then the figures indicating the water level inside the pressure vessel are no longer showing an increase. At 16:10 UTC, 13 March the injection of Sea Water was interrupted due to low level in a sea water supply reservoir. Sea Water injection was restored at 18:20 UTC 13 March.
Venting of the containment of Unit 3 started at 00:20 UTC, March 13. A small amount of radioactive material is thought to have been released from the exhaust duct.
There is a possibility that the valves in Unit 3 have failed. At the present time people on the scene are doing their utmost to resolve the malfunction of the valves in order to lower the air pressure inside reactor.
On 14 March:
02:01 UTC: NISA confirmed an explosion occurred at Unit 3.
04:15 UTC: NISA confirmed the following:
- There are no missing people following the Unit-3 explosion;
- The Unit-3 main control room remains operational after explosion;
- Based on no detected increase in radiation levels;
- NISA believes reactor pressure vessel and containment integrity remain intact.
05:40 UTC: NISA confirmed the following:
- Six people have been injured in the explosion
NISA could not confirm if there were one or two explosions
Emergency Response Manager
14-March-2011 06:50:00 UTC
IAEA Incident and Emergency Centre