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 12:00PM (EST), April 28, 2011
- 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 | 4/27 10:20AM | 4/27 10:10AM | 4/27 10:00AM | 4/27 11:56AM | 4/27 10:50AM | 4/27 10:40AM |
Nuclides (half-life) | Concentration (Unit : Bq/cm3) | |||||
I-131 (8 days) | 5.5 x 101 | 3.9 x 102 | 2.8 x 101 | 4.9 x 10-2 | 4.1 x 10-2 | 3.1 x 10-1 |
Cs-134 (2 years) | 5.3 x 101 | 2.1 x 101 | 2.8 x 100 | 1.2 x 10-1 | 6.6 x 10-2 | 2.4 x 10-1 |
Cs-137 (30 years) | 6.2 x 101 | 2.4 x 101 | 3.0 x 100 | 1.3 x 10-1 | 7.6 x 10-2 | 2.6 x 10-1 |
- 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 | |
4/27 7:06AM (a) | 4/27 6:59AM (b) | 4/27 1:50PM (c) | |||||
I-131 (8 days) | 6.3 x 101 | 1.0 x 101 | 2.0 x 10-2 | 4.0 x 10-2 | 1,600 | 250 | 0.5 |
Cs-134 (2 years) | 2.6 x 101 | 3.8 x 100 | 1.1 x 10-1 | 6.0 x 10-2 | 430 | 63 | 1.8 |
Cs-137 (30 years) | 2.7 x 101 | 4.0 x 100 | 1.1 x 10-1 | 9.0 x 10-2 | 300 | 44 | 1.2 |
- At 9:00PM (JST) on April 28, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 48 micro Sv/hour.
- At 9:00PM on April 28, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 21.8 micro Sv/hour.
- Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 7:00PM on April 28 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) | 0.415 | -0.016 | -0.055 | - | 0.007 | 0.013 |
4/28 5:00AM | 4/28 5:00AM | 4/28 5:00AM | - | 4/28 6:00AM | 4/28 6:00AM | |
pressure inside the primary containment vessel (absolute pressure, MPaabs) | 0.125 | 0.075 | 0.1017 | - | - | - |
4/28 5:00AM | 4/28 5:00AM | 4/28 5:00AM | - | - | - | |
water level inside the reactor core (meter) *1 | -1.65 | -1.5 | -1.85 | - | +2.081 | +2.138 |
4/28 5:00AM | 4/28 5:00AM | 4/28 5:00AM | - | 4/28 6:00AM | 4/28 6:00AM | |
temperature of the reactor vessel measured at the water supply nozzle (degrees Fahrenheit) | 225.1 | 247.8 | 186.8 | - | - | - |
4/28 6:00AM | 4/28 6:00AM | 4/28 6:00AM | - | - | - | |
temperature of the spent fuel pool (degrees Fahrenheit) | - | 122.0 | - | - | 104.7 | 80.6 |
- | 4/28 5:00AM | - | - | 4/28 6:00AM | 4/28 6:00AM | |
the temperature directly above the spent fuel pool by thermography measurement (degrees Fahrenheit) | 73.4 | - | 132.8 | 129.2 | - | - |
4/26 7:30AM | - | 4/26 7:30AM | 4/26 7:30AM |
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