Please find the updated information sheet below and attached that summarizes the events from Update-45 on 5/18.
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 May 25, 2011
All times listed below are Japan Standard Time (JST) unless otherwise noted.
- Reactor Core Status of Unit 2 and 3 at Fukushima Daiichi Nuclear Power Station
- On May 24, TEPCO announced the analysis result of the reactor core status of Unit 2 and 3 at Fukushima Daiichi Nuclear Power Station.
- According to the analysis, TEPCO proposed a more severe situation in which the water level gauges of reactor pressure vessels have not indicated the actual water level. In such case, TEPCO estimates that fuel pellets of Unit 2 and 3 melted and fell down to the bottom of reactor pressure vessel approximately 101 hours and 60 hours after the earthquake, respectively.
- TEPCO also estimates that most of the melted fuel is submerged and cooled with water at the bottom of reactor pressure vessel and damage to the reactor pressure vessels of Units 2 and 3 is limited.
- TEPCO believes that a large-scale release of radioactive materials is unlikely to occur in the future.
- The details are available at:
- Installation of Circulating Cooling System for Spent Fuel Pool at Unit 2
- On May 21, TEPCO submitted a report to the Nuclear and Industry Safety Agency (NISA) regarding the installation of 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.
- Currently, freshwater is being injected from time to time in order to compensate for the evaporated water.
- TEPCO plans to install the system by the end of May and evaluated that the water temperature will decrease to approximately 149.0 Fahrenheit 1.5 days after full operation and further decrease to 105.8 Fahrenheit one month later.
- The full version of the report is available at:
- Major Activities
- On May 21, the artificial floating island called “Mega-Float” which can accommodate approximately 10,000 tons of water arrived at Fukushima Daiichi Nuclear Power Station to temporarily receive low-level radioactive water which has accumulated in site buildings.
- 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 May 21, TEPCO announced results of the analysis of the water entering the ocean from a pit (a vertical portion of an underground structure for housing electric cables) of Unit 3. TEPCO estimated the total amount of water that entered the ocean was approximately 250m3 and that the total radiation content was approximately 2.0 x 1013 Bq. (As previously reported, the water was observed entering the ocean on May 11 and terminated on the same day.)
- 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 | 5/23 11:40AM | 5/23 11:45AM | 5/23 11:50AM | 5/23 11:31AM | 5/23 11:30AM | 5/23 11:20AM |
| Nuclides (half-life) | Concentration (Unit : Bq/cm3) | |||||
| I-131 (8 days) | 4.4 x 10-1 | 2.0 x 101 | 1.8 x 10-2 | Not Detectable | Not Detectable | Not Detectable |
| Cs-134 (2 years) | 6.2 x 100 | 1.9 x 101 | 1.6 x 10-1 | 4.7 x 10-2 | Not Detectable | 1.4 x 10-2 |
| Cs-137 (30 years) | 7.4 x 100 | 2.2 x 101 | 1.8 x 10-1 | 5.1 x 10-2 | Not Detectable | 1.5 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 | |
| 5/24 6:40AM (a) | 5/24 6:38AM (b) | 5/24 1:40PM (c) | |||||
| I-131 (8 days) | 7.9 x 100 | 4.7 x 10-1 | Not Detectable | 4.0 x 10-2 | 200 | 12 | - |
| Cs-134 (2 years) | 4.4 x 100 | 1.2 x 100 | 5.3 x 10-2 | 6.0 x 10-2 | 73 | 20 | 0.88 |
| Cs-137 (30 years) | 4.6 x 100 | 1.3 x 100 | 5.5 x 10-2 | 9.0 x 10-2 | 51 | 14 | 0.61 |
- At 9:00PM on May 25, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 15.5 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 May 25 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 May 25)
- Plant Status (As of May 16)
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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