Update to Information Sheet Regarding the Tohoku Earthquake
The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office
As of 9:40AM (EST), May 3, 2011
All times listed below are Japan Standard Time (JST) unless otherwise noted.
- 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 | 5/2 10:30AM | 5/2 10:35AM | 5/2 10:45AM | 5/2 11:23AM | 5/2 9:40AM | 5/2 9:35AM |
| Nuclides (half-life) | Concentration (Unit : Bq/cm3) | |||||
| I-131 (8 days) | 3.0 x 101 | 1.9 x 102 | 4.7 x 101 | 1.2 x 10-2 | Not Detectable | 5.9 x 10-2 |
| Cs-134 (2 years) | 3.4 x 101 | 2.0 x 101 | 2.7 x 101 | 1.0 x 10-1 | Not Detectable | 6.3 x 10-2 |
| Cs-137 (30 years) | 4.0 x 101 | 2.4 x 101 | 2.8 x 101 | 1.1 x 10-1 | Not Detectable | 7.1 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 | |
| 5/2 7:07AM (a) | 5/2 7:03AM (b) | 5/2 2:50PM (c) | |||||
| I-131 (8 days) | 2.3 x 102 | 4.6 x 101 | 2.1 x 10-2 | 4.0 x 10-2 | 5,800 | 1,200 | 0.53 |
| Cs-134 (2 years) | 5.4 x 100 | 4.7 x 100 | 7.9 x 10-2 | 6.0 x 10-2 | 90 | 78 | 1.3 |
| Cs-137 (30 years) | 5.6 x 100 | 5.0 x 100 | 7.3 x 10-2 | 9.0 x 10-2 | 62 | 56 | 0.81 |
- At 2:00PM on May 3, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 47 micro Sv/hour.
- At 2:00PM on May 3, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 19.8 micro Sv/hour.
- Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 4:00PM on May 3 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) | 0.455 | -0.023 | -0.070 | - | 0.003 | 0.018 |
| 5/3 11:00AM | 5/3 11:00AM | 5/3 11:00AM | - | 5/3 12:00PM | 5/3 12:00PM | |
| pressure inside the primary containment vessel (absolute pressure, MPaabs) | 0.135 | 0.070 | 0.1031 | - | - | - |
| 5/3 11:00AM | 5/3 11:00AM | 5/3 11:00AM | - | - | - | |
| water level inside the reactor core (meter) *1 | -1.7 | -1.5 | -1.85 | - | +1.551 | +2.421 |
| 5/3 11:00AM | 5/3 11:00AM | 5/3 11:00AM | - | 5/3 12:00PM | 5/3 12:00PM | |
| temperature of the reactor vessel measured at the water supply nozzle (degrees Fahrenheit) | 287.4 | 243.1 | 241.9 |
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