Dear Friends,
Please find the updated information sheet below and attached that summarizes the events from Update-47 on 6/1.
For your reference, JAIF (Japan Atomic Industrial Forum) has been posting the translation of news reports on their website. http://www.jaif.or.jp/english/
Please direct any questions regarding this document to me, Ishida@denjiren.com or Samuel Lederer, Researcher of FEPC at lederer@denjiren.com.
Update to Information Sheet Regarding the Tohoku Earthquake
The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office
As of June 10, 2011
All times listed below are Japan Standard Time (JST) unless otherwise noted.
- Report of the Japanese Government to IAEA
- On June 7, the Japanese Government announced the “Report of Japanese Government to the IAEA Ministerial Conference on Nuclear Safety,” a summary of the evaluation of the Fukushima Daiichi accident and the lessons learned based on the facts known about the situation so far.
- A summary of the report is attached and the full version of the report is available at :
- The preliminary summary report of IAEA International Fact Finding Expert Mission (May 24 - June 1) is available at :
- Reactor Core Status of Unit 1, 2 and 3 at Fukushima Daiichi Nuclear Power Station
- On June 6, Nuclear and Industry Safety Agency (NISA) announced the analysis result of the reactor core status of Unit 1, 2 and 3 at Fukushima Daiichi Nuclear Power Station.
- The estimated time of occurrence and the comparison with TEPCO analysis are as follows:
Approximate time after the earthquake | Exposure of fuel assemblies | Damage to fuel assemblies | Damage to Reactor Pressure Vessel | |
Unit 1 | NISA | 2 hours | 3 hours | 5 hours |
TEPCO | 3 hours | 4 hours | 15 hours | |
Unit 2 | NISA | 75 hours | 77 hours | 80 hours |
TEPCO | 75 hours | 77 hours | 109 hours | |
Unit 3 | NISA | 41 hours | 44 hours | 79 hours |
TEPCO | 40 hours | 42 hours | 66 hours |
- According to the NISA report, the general progression of the events was similar to TEPCO’s analysis. However, the damage of reactor pressure vessels was estimated to begin earlier. NISA explained these discrepancies arose from parameter settings of analysis.
- Major Activities
- On June 3, TEPCO installed a temporary reactor pressure gauge at Unit 1.
- On June 7, preparation work to reinforce the supporting structure of spent fuel pool at Unit 4 commenced.
- On June 8, TEPCO announced that Unit 1 and 2 lost electricity in the control room at 2:20PM due to a malfunction of a power distribution board. The power supply was restored at 5:32PM. During this time, cooling operations were not interrupted.
- Other countermeasures such as injecting water into reactor cores, injecting Nitrogen gas into primary containment vessels, shooting water aimed at spent fuel pools, transferring accumulated water, and dispersing dust inhibitor over the ground continue to be implemented.
- Radiation Levels
- On June 10, TEPCO announced that two employees who worked at Fukushima Daiichi were exposed to the radiation at 678.08mSv and 643.07mSv respectively. The upper limit of radiation dosage for workers at Fukushima Daiichi had been temporarily raised from 100mSv to 250mSv as an emergency measure by the government in March. No negative health effects of the workers have been reported.
- 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 | 6/8 11:35AM | 6/8 11:30AM | 6/8 12:25PM | 6/8 11:42AM | 6/8 11:43AM | 6/8 11:47AM |
Nuclides (half-life) | Concentration (Unit : Bq/cm3) | |||||
I-131 (8 days) | 5.0 x 10-1 | 1.3 x 100 | 8.4 x 10-1 | 1.2 x 10-2 | Not Detectable | Not Detectable |
Cs-134 (2 years) | 1.1 x 101 | 1.1 x 101 | 4.4 x 10-1 | 2.9 x 10-2 | 6.7 x 10-3 | 1.2 x 10-2 |
Cs-137 (30 years) | 1.4 x 101 | 1.3 x 101 | 4.6 x 10-1 | 3.5 x 10-2 | Not Detectable | 9.1 x 10-3 |
- 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 | |
6/9 6:45AM (a) | 6/9 6:50AM (b) | 6/9 1:25PM (c) | |||||
I-131 (8 days) | 1.8 x 100 | 3.5 x 10-1 | Not Detectable | 4.0 x 10-2 | 45 | 8.8 | - |
Cs-134 (2 years) | 1.7 x 100 | 7.0 x 10-1 | 2.8 x 10-2 | 6.0 x 10-2 | 28 | 12 | 0.47 |
Cs-137 (30 years) | 1.9 x 100 | 7.6 x 10-1 | 2.8 x 10-2 | 9.0 x 10-2 | 21 | 8.4 | 0.31 |
- At 2:00PM on June 10, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 14.0 micro Sv/hour. Other monitoring data at the site are available at:
- Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 6:00PM on June 10 are shown in the attached PDF file. Previous data are available at: http://www.mext.go.jp/
english/incident/1304082.htm
- Plant Parameters (As of 6:00AM on June 10)
- Plant Status (As of June 6)
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)
++++++++++++++++++++++++++++++
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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