Michele Kearney's Nuclear Wire

Major Energy and Environmental News and Commentary affecting the Nuclear Industry.

Friday, April 29, 2011

FEPC Update to Information Sheet Regarding the Tohoku Earthquake 4/29

Update to Information Sheet Regarding the Tohoku Earthquake
The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office
As of 11:00AM (EST), April 29, 2011
All times listed below are Japan Standard Time (JST) unless otherwise noted.
  • Radiation Levels
    • On April 29, 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 April 28. The concentration of radioactive nuclides were as follows:

Nuclides
(half-life)
Concentration (Unit : Bq/cm3)
Sampled on April 28
(Reference)
Sampled on April 12
(Reference) Sampled on March 4
I-131
(8 days)
2.7 x 101
2.2 x 102
Under the Detection Limit
Cs-134
(2 years)
4.9 x 101
8.8 x 101
Under the Detection Limit
Cs-137
(30 years)
5.5 x 101
9.3 x 101
1.3 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
4/28 6:59AM
  (a)
4/28
6:54AM
(b)
4/28 2:00PM
(c)
I-131
(8 days)
1.2 x 102
1.4 x 101
1.1 x 10-2
4.0 x 10-2
3,000
350
0.28
Cs-134
(2 years)
2.1 x 101
3.8 x 100
8.0 x 10-2
6.0 x 10-2
350
63
1.3
Cs-137
(30 years)
2.1 x 101
4.0 x 100
7.6 x 10-2
9.0 x 10-2
230
44
0.84

    • At 9:00PM on April 29, 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 29, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 21.4 micro Sv/hour.
    • Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 4:00PM on April 29 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)
0.410
-0.020
-0.060
-
0.007
0.013
4/29
11:00AM
4/29
11:00AM
4/29
11:00AM
-
4/29
1:00PM
4/29
1:00PM
pressure inside the primary containment vessel (absolute pressure, MPaabs)
0.105
0.075
0.1033
-
-
-
4/29
11:00AM
4/29
11:00AM
4/29
11:00AM
-
-
-
water level inside the reactor core (meter) *1
-1.7
-1.5
-1.85
-
+1.901
+1.965
4/29
11:00AM
4/29
11:00AM
4/29
11:00AM
-
4/29
1:00PM
4/29
1:00PM
temperature of the reactor vessel measured at the water supply nozzle (degrees Fahrenheit)
238.5
246.6
177.1
-
-
-
4/29
...

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