Please find the updated information sheet below and attached that summarizes the events from Update-46 on 5/25.
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 1, 2011
All times listed below are Japan Standard Time (JST) unless otherwise noted.
- Operation of Circulating Cooling System for Spent Fuel Pool at Unit 2
- On May 31, TEPCO began to operate a circulating cooling system at the spent fuel pool of Unit 2 to remove decay heat of the spent fuel continuously in order to maintain the water level and ensure the cooling of water in the pool.
- TEPCO plans to decrease the current temperature of approximately 158 degrees Fahrenheit to 104 degrees Fahrenheit one month later.
- As of 11:00AM on June 1, the temperature of the spent fuel pool was 136.4 degrees Fahrenheit.
- Press Release of Pictures of Tsunami and Damages
- On May 25, TEPCO released a report which contains pictures of tsunami and damage, events and plant status etc. This report is available at:
- Major Activities
- On May 27, TEPCO began to disperse dust suppressant over the reactor and turbine buildings in order to prevent diffusion of radioactive materials. (In the past, TEPCO dispersed dust suppressant over the ground around the buildings.)
- On May 28, TEPCO discovered that the temporary RHRS (Residual Heat Removal System) pumps of Unit 5 had malfunctioned. On May29, TEPCO replaced these pumps and restored their cooling function.
- On May 31, an explosion was heard near the south side of Unit 4 secondary containment building. TEPCO believes that the sound was caused by the accidental explosion of an Oxygen container in debris that was in the process of being removed by a remote controlled excavation machine. No injuries or changes of radiation level have been reported as a result of the explosion.
- 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
- 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 | 5/30 12:00PM | 5/30 12:10PM | 5/30 12:15PM | 5/30 11:48AM | 5/30 11:50AM | 5/30 11:40AM |
Nuclides (half-life) | Concentration (Unit : Bq/cm3) | |||||
I-131 (8 days) | 4.1 x 100 | 6.0 x 100 | Not Detectable | 2.3 x 10-1 | Not Detectable | Not Detectable |
Cs-134 (2 years) | 7.4 x 101 | 1.6 x 101 | 1.6 x 10-1 | 1.5 x 10-1 | Not Detectable | 1.3 x 10-2 |
Cs-137 (30 years) | 8.8 x 101 | 1.9 x 101 | 1.4 x 10-1 | 1.6 x 10-1 | Not Detectable | 2.0 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 | |
5/31 6:51AM (a) | 5/31 6:55AM (b) | 5/29 1:10PM (c) | |||||
I-131 (8 days) | 1.2 x 100 | 9.6 x 10-1 | Not Detectable | 4.0 x 10-2 | 30 | 24 | - |
Cs-134 (2 years) | 7.4 x 100 | 1.7 x 100 | 6.2 x 10-2 | 6.0 x 10-2 | 120 | 28 | 1.0 |
Cs-137 (30 years) | 7.8 x 100 | 1.9 x 100 | 6.9 x 10-2 | 9.0 x 10-2 | 87 | 21 | 0.77 |
- At 9:00PM on June 1, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 14.7 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 7:00PM on June 1 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 7:00AM on June 1)
- Plant Status (As of May 31)
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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