Update to Information Sheet Regarding the Tohoku Earthquake
The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office
As of May 18, 2011
All times listed below are Japan Standard Time (JST) unless otherwise noted.
- Reactor Core Status of Unit 1 at Fukushima Daiichi Nuclear Power Station
- On May 15, TEPCO announced the analysis result of the reactor core status of Unit 1 at Fukushima Daiichi Nuclear Power Station.
- According to the analysis, TEPCO estimates that fuel pellets of Unit 1 melted and fell down to the bottom of reactor pressure vessel at a relatively early stage (approximately 16 hours) after the earthquake.
- TEPCO also estimates that most of the melted fuel is submerged and cooled with water at the bottom of reactor pressure vessel and the damage of reactor pressure vessel is limited.
- TEPCO believes that a large-scale release of radioactive materials is unlikely to occur in the future.
- The details are available at:
- Roadmap
- On May 17, TEPCO revised “the Roadmap towards Restoration from the Accident at Fukushima Daiichi Nuclear Power Station” which reflects the progress and the change of the situation during a month since TEPCO first announced the roadmap on April 17.
- TEPCO did not change the time frame for achieving stable cooling by mid-July and cold shutdown within 3 to 6 months after the stable cooling.
- Reflecting the recently discovered leakage of water from the primary containment vessel of Unit 1 in addition to Unit 2, TEPCO presumes some water leakage at Unit 3.TEPCO has decided to prioritize the establishment of a liquid cooling function instead of flooding the primary containment vessel with water. In this system, the accumulated water in the site buildings will be decontaminated, desalinated, then injected by pumps the reactor to provide cooling in a closed loop system.
- The details are attached on this email and also available at:
- Fukushima Daiichi Unit 1 reactor
- On May 10 and 11, TEPCO implemented the calibration of the water level gauge of the reactor pressure vessel.
- On May 11, TEPCO implemented the calibration of the pressure gauge of the primary containment vessel.
- On May 13, TEPCO commenced preparation work to cover the reactor building with fabric. The cover will be installed as an emergency measure to prevent the diffusion of radioactive materials until mid-to-long term measures are implemented.
- Fukushima Daiichi Unit 2 reactor
- On May 12, transferring of the accumulated water at the turbine building to the Central Radioactive Waste Disposal Facility commenced.
- Fukushima Daiichi Unit 3 reactor
- On May 17, transferring of the accumulated water in the turbine building to the Central Radioactive Waste Disposal Facility commenced.
- Fukushima Daiichi Unit 4 reactor
- On May 9, TEPCO commenced preparation work to install a support structure under the spent fuel pool.
- Fukushima Daiichi Unit 6 reactor
- On May 12, 13, 14, 15, 16 and 18, accumulated water in the turbine building was transferred to a temporary tank.
- On May 12, 13 and 17, accumulated water in the reactor building was transferred to a waste treatment building.
- Radiation Levels
- On May 15, TEPCO announced the result of the analysis of water samples from the Common Spent Fuel Pool at Fukushima Daiichi Nuclear Power Plant taken on May 13. The concentration of radioactive nuclides were as follows:
Nuclides (half-life) | Concentration (Unit : Bq/cm3) | |
Sampled on May 13 | (Reference) Sampled on February 10 | |
I-131 (8 days) | Under the Detection Limit | Under the Detection Limit |
Cs-134 (2 years) | 1.7 x 10-1 | Under the Detection Limit |
Cs-137 (30 years) | 1.2 x 100 | Under the Detection Limit |
- The concentration of radioactive nuclides from the groundwater sampled at sub-drain pits at Unit 1 to 6 of Fukushima Daiichi Nuclear Power Station were as follows:
Unit 1 | Unit 2 | Unit 3 | Unit 4 | Unit 5 | Unit 6 | |
Samples taken at | 5/16 1:44PM | 5/16 1:40PM | 5/16 1:52PM | 5/16 11:44AM | 5/16 1:32PM | 5/16 1:20PM |
Nuclides (half-life) | Concentration (Unit : Bq/cm3) | |||||
I-131 (8 days) | 3.2 x 100 | 3.8 x 101 | 1.4 x 10-1 | 3.6 x 10-2 | Not Detectable | Not Detectable |
Cs-134 (2 years) | 1.5 x 101 | 2.8 x 101 | 2.4 x 10-1 | 8.0 x 10-2 | Not Detectable | 3.0 x 10-2 |
Cs-137 (30 years) | 1.7 x 101 | 3.4 x 101 | 2.8 x 10-1 | 8.5 x 10-2 | Not Detectable | 2.4 x 10-2 |
- The concentration of radioactive nuclides from the seawater sampled at the screen device (installed to remove waste before the intake of seawater) of Unit 2 and sampled near the seawater discharge point (south side) of Fukushima Daiichi Nuclear Station were as follows:
Nuclides (half-life) | Concentration (Unit : Bq/cm3) | Ratio | |||||
Sampled inside the silt fence at the screen of Unit 2 | Sampled outside the silt fence at the screen of Unit 2 | Sampled at south side discharge point | Maximum Permissible Water Concentration (d) | a / d | b / d | c / d | |
5/17 6:58AM (a) | 5/17 6:53AM (b) | 5/17 2:00PM (c) | |||||
I-131 (8 days) | 2.5 x 101 | 2.2 x 100 | Not Detectable | 4.0 x 10-2 | 630 | 55 | - |
Cs-134 (2 years) | 1.0 x 101 | 8.2 x 100 | 4.3 x 10-2 | 6.0 x 10-2 | 170 | 140 | 0.72 |
Cs-137 (30 years) | 1.1 x 101 | 8.7 x 100 | 3.6 x 10-2 | 9.0 x 10-2 | 120 | 97 | 0.40 |
- At 2:00PM on May 18, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 16.4 micro Sv/hour.
- Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 7:00PM on May 18 are shown in the attached PDF file. English version is available at: http://www.mext.go.jp/
english/incident/1304082.htm - For comparison, a human receives 2,400 micro Sv per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6,900 micro Sv per scan.
- Plant Parameters (As of 12:00AM on May 18)
Our official sources are:
- Office of The Prime Minister of Japan
- Nuclear and Industrial Safety Agency (NISA)
- Tokyo Electric Power Company (TEPCO) Press Releases
- Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- Ministry of Defense (MOD)
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Taro Ishida
The Federation of Electric Power Companies of Japan
1901 L Street, NW Suite 600
Washington, DC 20036
1901 L Street, NW Suite 600
Washington, DC 20036
Mobile (202) 253-2579
Phone (202) 530-0769 (Direct)
Phone (202) 466-6781
Fax (202) 466-6758
Phone (202) 466-6781
Fax (202) 466-6758
email: ishida@denjiren.com
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