Please find the updated information sheet below and attached that summarizes the events from Update-41 at 9:00AM on 5/6.
For your reference, JAIF (Japan Atomic Industrial Forum) has been posting the translation of news reports on their website.
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 9:30AM (EST), May 9, 2011
All times listed below are Japan Standard Time (JST) unless otherwise noted.
- Radiation Levels
- On May 9, TEPCO announced the result of the analysis of water samples from the spent fuel pool at Unit 4 of Fukushima Daiichi Nuclear Power Plant taken on May 7. The concentration of radioactive nuclides were as follows:
Nuclides (half-life) | Concentration (Unit : Bq/cm3) | |||
Sampled on May 7 | (Reference) Sampled on April 28 | (Reference) Sampled on April 12 | (Reference) Sampled on March 4 | |
I-131 (8 days) | 1.6 x 101 | 2.7 x 101 | 2.2 x 102 | Under the Detection Limit |
Cs-134 (2 years) | 5.6 x 101 | 4.9 x 101 | 8.8 x 101 | Under the Detection Limit |
Cs-137 (30 years) | 6.7 x 101 | 5.5 x 101 | 9.3 x 101 | 1.3 x 10-1 |
- 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 | 5/6 2:15PM | 5/6 2:25PM | 5/6 2:31PM | 5/6 11:17AM | 5/6 2:03PM | 5/6 1:46PM |
Nuclides (half-life) | Concentration (Unit : Bq/cm3) | |||||
I-131 (8 days) | 7.1 x 100 | 1.4 x 102 | 5.8 x 100 | 1.6 x 10-2 | 1.5 x 10-2 | 4.0 x 10-2 |
Cs-134 (2 years) | 1.4 x 101 | 1.5 x 101 | 9.0 x 10-1 | 6.2 x 10-2 | Not Detectable | 4.9 x 10-2 |
Cs-137 (30 years) | 1.7 x 101 | 1.8 x 101 | 9.5 x 10-1 | 4.9 x 10-2 | 2.2 x 10-2 | 6.9 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 | |
5/8 6:55AM (a) | 5/8 7:00AM (b) | 5/8 1:55PM (c) | |||||
I-131 (8 days) | 5.6 x 100 | 2.1 x 100 | Not Detectable | 4.0 x 10-2 | 140 | 53 | - |
Cs-134 (2 years) | 4.9 x 100 | 1.7 x 100 | 4.9 x 10-2 | 6.0 x 10-2 | 82 | 28 | 0.82 |
Cs-137 (30 years) | 5.1 x 100 | 1.7 x 100 | 6.6 x 10-2 | 9.0 x 10-2 | 57 | 19 | 0.73 |
- At 2:00PM on May 9, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 44 micro Sv/hour.
- At 2:00PM on May 9, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 18.0 micro Sv/hour.
- Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 4:00AM on May 9 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
Unit 1 | Unit 2 | Unit 3 | Unit 4 | Unit 5 | Unit 6 | |
pressure inside the reactor core (gauge pressure, MPa) | 0.465 | -0.020 | -0.081 | - | 0.006 | 0.013 |
5/9 11:00AM | 5/9 11:00AM | 5/9 11:00AM | - | 5/9 12:00PM | 5/9 12:00PM | |
pressure inside the primary containment vessel (absolute pressure, MPaabs) | 0.120 | 0.060 | 0.1026 | - | - | - |
5/9 11:00AM | 5/9 11:00AM | 5/9 11:00AM | - | - | - | |
water level inside the reactor core (meter) *1 | -1.65 | -1.5 | -1.9 | - | +1.643 | +2.083 |
5/9 11:00AM | 5/9 11:00AM | 5/9 11:00AM | - | 5/9 12:00PM | 5/9 12:00PM | |
temperature of the reactor vessel measured at the water supply nozzle (degrees Fahrenheit) | 241.9 | 240.1 | 421.5 | - | - | - |
5/9 11:00AM | 5/9 11:00AM | 5/9 11:00AM | - | - | - | |
temperature of the spent fuel pool (degrees Fahrenheit) |
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