Wednesday, May 4, 2011

Update to Information Sheet Regarding the Tohoku Earthquake 5/4

Update to Information Sheet Regarding the Tohoku Earthquake
The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office
As of 10:00AM (EST), May 4, 2011
All times listed below are Japan Standard Time (JST) unless otherwise noted.
  • Radiation Levels
    • 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
5/3
6:50AM
  (a)
5/3
6:46AM
(b)
5/3
1:40PM
(c)
I-131
(8 days)
5.6 x 101
4.1 x 100
Not Detectable
4.0 x 10-2
1,400
100
-
Cs-134
(2 years)
4.4 x 100
2.3 x 100
4.8 x 10-2
6.0 x 10-2
73
38
0.8
Cs-137
(30 years)
4.5 x 100
2.4 x 100
5.9 x 10-2
9.0 x 10-2
50
27
0.66

    • At 2:00PM on May 4, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 46 micro Sv/hour.
    • At 2:00PM on May 4, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 19.1 micro Sv/hour.
    • Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 1:00PM on May 4 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)
0.450
-0.020
-0.077
-
0.003
0.016
5/4
11:00AM
5/4
11:00AM
5/4
11:00AM
-
5/4
12:00PM
5/4
12:00PM
pressure inside the primary containment vessel (absolute pressure, MPaabs)
0.135
0.065
0.1033
-
-
-
5/4
11:00AM
5/4
11:00AM
5/4
11:00AM
-
-
-
water level inside the reactor core (meter) *1
-1.7
-1.5
-1.8
-
+1.989
+2.313
5/4
11:00AM
5/4
11:00AM
5/4
11:00AM
-
5/4
12:00PM
5/4
12:00PM
temperature of the reactor vessel measured at the water supply nozzle (degrees Fahrenheit)
279.5
242.6
263.3
-
-
-
5/4
11:00AM
5/4
11:00AM
5/4
11:00AM
-
-
-
temperature of the spent fuel pool (degrees Fahrenheit)
-
120.2
-
-
105.4
96.8
-
5/4
11:00AM
-
-
5/4
12:00PM
5/4
12:00PM
Amount of water in total shot/injected to the spent fuel storage pool (tons)
90
642 - 657
5,390.5
3,306.2
-
-
as of 5/1
5:00PM
as of 5/1
5:00PM
as of 5/1
5:00PM
as of 5/1
5:00PM
-
-
*1: A negative figure indicates that the water level is below the top of the fuel rods.

  • Fukushima Daiichi Unit 1 reactor
    • As of 3:00PM on May 4, injection of nitrogen gas into the primary containment vessel to prevent an explosion by accumulated hydrogen gas continues.
    • As of 3:00PM on May 4, the injection of freshwater into the reactor core continues.
  • Fukushima Daiichi Unit 2 reactor
    • As of 3:00PM on May 4, the injection of freshwater into the reactor core continues.
  • Fukushima Daiichi Unit 3 reactor
    • As of 3:00PM on May 4, the injection of freshwater into the reactor core continues.

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