FEPC Update to Information Sheet Regarding the Tohoku Earthquake 4/15
Update to Information Sheet Regarding the Tohoku Earthquake
The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office
As of 11:50AM (EST), April 15, 2011
For your reference, JAIF (Japan Atomic Industrial Forum) has been posting the translation of news reports on their website.
- Radiation Levels
- On April 14, TEPCO announced the results of the analysis of groundwater samples from sub-drain pits at Unit 1 to 6 of Fukushima Daiichi Nuclear Power Station. The concentration of radioactive nuclides were as follows:
Unit 1 | Unit 2 | Unit 3 | Unit 4 | Unit 5 | Unit 6 | |
Samples taken at | 4/13 11:40AM | 4/13 11:50AM | 4/13 11:25AM | 4/13 11:20AM | 4/13 12:00PM | 4/13 12:10PM |
Nuclides (half-life) | Concentration (Unit : Bq/cm3) | |||||
I-131 (8 days) | 4.0 x 102 | 6.1 x 102 | 3.6 x 100 | 1.7 x 101 | 1.6 x 10-1 | 1.9 x 10-1 |
Cs-134 (2 years) | 5.3 x 101 | 7.9 x 100 | 2.4 x 100 | 2.7 x 100 | 2.7 x 10-1 | 2.6 x 10-1 |
Cs-137 (30 years) | 6.0 x 101 | 9.1 x 100 | 2.4 x 100 | 2.7 x 100 | 2.8 x 10-1 | 2.8 x 10-1 |
- On April 15, TEPCO announced the result of discharge of low level radioactive water stored at the Central Radioactive Waste Disposal Facility and accumulated water at the sub-drain pits of Unit 5 and 6 to the ocean. The details are available at: http://www.tepco.co.jp/en/
press/corp-com/release/ 11041507-e.html
§ The total radioactive content of discharge: approximately 1.5 x 1011 Bq
§ Discharge amount from the Central Radioactive Waste Disposal Facility: approximately 9,070 tons (from 7:03PM on April 4 to 5:40PM on April 10)
§ Discharge amount from sub-drain pits of Unit 5 and 6: approximately 1,323 tons (from 9:00PM on April 4 to 6:52PM on April 9)
§ TEPCO has not detected major changes of the concentration of nuclides in the seawater sampled at several measuring points near Fukushima Daiichi Nuclear Power Station, compared with the samples that were taken during the week before the discharge.
(As reported on April 4, these discharges were performed in order to accommodate higher level radioactive water in the Central Radioactive Waste Disposal Facility and to prevent important equipment of Unit 5 and 6 from being submerged.)
- 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 at the screen of Unit 2 at 7:40AM on April 14 (a) | Sampled at south side discharge point at 2:00PM on April 14 (b) | Maximum Permissible Water Concentration (c) | a / c | b / c | |
I-131 (8 days) | 4.2 x 101 | 1.2 x 100 | 4.0 x 10-2 | 1,100 | 30 |
Cs-134 (2 years) | 3.3 x 101 | 7.9 x 10-1 | 6.0 x 10-2 | 550 | 13 |
Cs-137 (30 years) | 3.3 x 101 | 8.1 x 10-1 | 9.0 x 10-2 | 370 | 9 |
- At 4:00PM (JST) on April 15, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 69 micro Sv/hour.
- At 4:00PM on April 15, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 35.8 micro Sv/hour.
- Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 7:00PM on April 15 are shown in the attached PDF file. English version is available at: http://www.mext.go.jp/
english/radioactivity_level/ detail/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) | 0.430 | -0.018 | -0.021 | - | 0.003 | 0.009 |
4/15 12:00PM | 4/15 12:00PM | 4/15 12:00PM | - | 4/15 2:00PM | 4/15 2:00PM | |
pressure inside the primary containment vessel (absolute pressure, MPaabs) | 0.190 | 0.090 | 0.104 | - | - | - |
4/15 12:00PM | 4/15 12:00PM | 4/15 12:00PM | - | - | - | |
water level inside the reactor core (meter) *1 | -1.65 | -1.5 | -1.8 | - |
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