Update: For the latest bulletins, please see my new article:
Japan's Nuclear Emergency - The Straight Goods - Update

original post begins here:
Japan's Nuclear Emergency - The Straight Goods

There is much speculative and inaccurate reporting in the world's media regarding the problems caused to nuclear power facilities in Japan by the recent earthquake.

The Tokyo Electric Power Company - TEPCO - is releasing frequent updates on the emergency situation which followed the earthquake.

Their web site is getting very heavy traffic at the moment, so I reproduce here two of their most recent news updates as a public service to counter the speculation.

Press Release (Mar 12,2011)
Occurrence of a Specific Incident Stipulated in Article 15, Clause 1 of the Act on Special Measures Concerning Nuclear Emergency Preparedness (Unit 1)

At 2:48PM on March 11th, the reactor of Fukushima Daini Nuclear Power Station Unit 1 (Boiling Water Reactor, rated output 1,100 Megawatts) shut down due to the impact of the earthquake.

Reactor Core Isolation Cooling System was used to inject water into the reactor to cool it.  Today at 3:48AM, water injection by Make-up Water Condensate System begun.
Subsequently, at 5:22AM, the temperature of the suppression chamber exceeded 100 degrees.
As the reactor pressure suppression function was lost, at 5:22AM, it was determined that a specific incident stipulated in article 15, clause 1 has occurred.

Safety and Impact to the Environment
- Currently, water level to cool irradiated fuels in the reactor is maintained.
- Indication of monitoring posts installed in the site boundary is not different from normal.  Currently, no radiation impact to the external environment has been confirmed.

We will continue monitoring in detail discharge of radioactive material from exhaust stack and discharge canal.


Press Release (Mar 12,2011)
Impact to TEPCO's Facilities due to Miyagiken-Oki Earthquake (as of 7 AM)

Below is major impact to TEPCO's facilities due to the Miyagiken-Oki Earthquake that occurred yesterday at 2:46PM.
*new items are underlined [my edit - not underlined but bold italics]

[Nuclear Power Station]
Fukushima Daiichi Nuclear Power Station:
  Units 1 to 3: shutdown due to earthquake
  Units 4 to 6: outage due to regular inspection
* Evacuation has been instructed by the national government to the local residents within 10 km radius of Fukushima Daiichi Nuclear Power Station and Fukushima Daini Nuclear Power Station.
* Measurement of radioactive material (Iodine, etc.) by monitoring car indicates increasing value compared to normal level. One of the monitoring posts is also indicating higher than normal level. We will continue monitoring discharge of radioactive material from exhaust stack and discharge canal, etc.
* We have decided to implement measures to reduce the pressure of the reactor containment vessel for those units that cannot confirm certain level of water injection by the Reactor Core Isolation Cooling System, in order to fully secure safety.

Fukushima Daini Nuclear Power Station:
  Units 1 to 4: shutdown due to earthquake

Kashiwazaki Kariwa Nuclear Power Station:
  Units 1, 5, 6, 7: normal operation
  Units 2 to 4: outage due to regular inspection

*There was no shutdown due to the earthquake occurred in the northern part of Nagano Prefecture at around 3:58AM today.
* Survey data on radiation by exhaust stack monitors and monitoring cars have indicated no departure from normal level for all nuclear power stations.

[Thermal Power Station]
Hirono Thermal Power Station Units 2 and 4: shutdown due to earthquake
Hitachinaka Thermal Power Station Unit 1: shutdown due to earthquake
Kashima Thermal Power Station Units 2, 3, 5, 6: shutdown due to earthquake
Chiba Thermal Power Station Unit 2 Axis 1: shutdown due to earthquake
Ohi Thermal Power Station Units 2, 3: shutdown due to earthquake
Goi Thermal Power Station Unit 4: had been shutdown due to earthquake but has restarted
Higashi-Ohgishima Thermal Power Station Unit 1: shutdown due to earthquake

[Hydro Power Station]
11 stations in Fukushima Prefecture, 1 station in Tochigi Prefecture,
3 stations in Yamanashi Prefecture, were shutdown due to earthquake.
Power stations in Gunma Prefecture have been restored.

[Transmission System, etc.]
Eight substations shown below have been shutdown:
- Naka Substation
- Shin Motegi Substation
- Joban Substation
- Ibaraki Substation
- Ishioka Substation
- Nishi Mito Substation
- Kawachi Substation
- Haga Substation
- Mito Hokubu Substation

[Blackout in TEPCO's Service Area]
Total of about 1.17 million households are out of power.
Tokyo: 0
Kanagawa Pref.: 0
Tochigi Pref.: 296,363
Chiba Pref.: 211,944
Saitama Pref: 0
Gunma Pref.: 12
Ibaraki Pref: 662,189
Yamanashi Pref: 0
Shizuoka Pref: 11,819 (east of Fuji River)

[Supply and Demand Status within TEPCO's Service Area to Secure Stable Power Supply]  
Backup supply from Shinshinano Conversion Station: 600MW
Backup supply from Sakuma Conversion Station: 300MW
Backup supply from Higashi Shimizu Conversion Station: 100MW

Because TEPCO's facilities have been seriously damaged, power shortage may occur.
TEPCO appreciates customers' cooperation in reducing electricity usage by avoiding using unnecessary lighting and electrical equipment.

We are taking all measures to restore power, however, we expect extremely difficult situation in power supply for tomorrow as well.
We kindly ask our customers to cooperate with us in reducing usage of  power.

Please do NOT touch cut-off electric wires.