Do other people find these information sheets useful?  I am debating about whether to keep posting them.

My fascination with the events unfolding at Fukushima is slowly giving way to the fact that I still have a day job that deals with other topics.

 

Update to Information Sheet Regarding the Tohoku Earthquake

The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office

As of 3:00PM (EST), April 7, 2011

  • Radiation Levels

o      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 6  (a) Sampled at south side discharge point at 2:05PM on April 6  (b) Maximum Permissible Water Concentration (c) a / c b / c
I-131

(8 days)

5.6 x 103 3.7 x 100 4.0 x 10-2 140,000 93
Cs-134

(2 years)

3.1 x 103 2.4 x 100 6.0 x 10-2 52,000 40
Cs-137

(30 years)

3.2 x 103 2.5 x 100 9.0 x 10-2 36,000 28

 

o      At 6:00PM (JST) on April 7, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 99 micro Sv/hour.

o      At 6:00PM on April 7, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 56.8 micro Sv/hour.

o      Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 7:00PM on April 7 are shown in the attached PDF file. English version is available at:    http://www.mext.go.jp/english/radioactivity_level/detail/1304082.htm

o      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) 0.375 -0.009 0.000 - 0.002 0.008
4/7

12:00PM

4/7

12:00PM

4/7

12:00PM

- 4/7

12:00PM

4/7

12:00PM

pressure inside the primary containment vessel (absolute pressure, MPaabs) 0.165 0.100 0.1059 - - -
4/7

12:00PM

4/7

12:00PM

4/7

12:00PM

- - -
water level inside the reactor core (meter) *1 -1.65 -1.5 -1.9 - +1.801 +1.816
4/7

12:00PM

4/7

12:00PM

4/7

12:00PM

- 4/7

12:00PM

4/7

12:00PM

temperature of the reactor vessel measured at the water supply nozzle (degrees Fahrenheit) 434.8 290.5 190.9

*2

- - -
4/7

12:00PM

4/7

12:00PM

4/7

12:00PM

- - -
temperature of the spent fuel pool (degrees Fahrenheit) - 123.8 - - 96.8 69.8
- 4/7

12:00PM

- - 4/7

12:00PM

4/7

12:00PM

the temperature directly above the spent fuel pool by thermography measurement (degrees Fahrenheit) 75.2 - 140.0 134.6 - -
4/6

7:30AM

- 4/6

7:30AM

4/6

7:30AM

- -
temperature directly above the primary containment vessel (degrees Fahrenheit) 84.2 - 89.6 - - -
4/6

7:30

- 4/6

7:30

- - -
temperature directly above the second containment building (degrees Fahrenheit) - 89.6 - - - -
- 4/6

7:30

- - - -
Amount of water in total shot/injected to the spent fuel storage pool (tons) 90 299 – 314 5,048 1,493 - -
as of 4/7

7:00PM

as of 4/7

7:00PM

as of 4/7

7:00PM

as of 4/7

7:00PM

- -

*1: Minus figure means that water level is below the top of the fuel rods.

*2: This figure is under investigation.

 

  • Fukushima Daiichi Unit 1 reactor

o      At 1:31AM on April 7, TEPCO began the injection of nitrogen gas into the primary containment vessel to prevent an explosion by accumulated hydrogen gas.

o      As of 3:30PM on April 7, the injection of freshwater into the reactor core continues.

  • Fukushima Daiichi Unit 2 reactor

o      At 1:29PM on April 7, TEPCO began to inject freshwater into the spent fuel pool, until 2:34PM (approximately 36 tons in total).

o      As of 3:30PM on April 7, the injection of freshwater into the reactor core continues.

  • Fukushima Daiichi Unit 3 reactor

o      At 6:53AM on April 7, TEPCO began to shoot water aimed at the spent fuel pool, until 8:53AM, with a specialized vehicle normally used for pumping concrete (approximately 70 tons in total).

o      As of 3:30PM on April 7, the injection of freshwater into the reactor core continues.

  • Fukushima Daiichi Unit 4 reactor

o      At 6:23PM on April 7, injection of freshwater into the spent fuel pool commenced.

  • Fukushima Daiichi Common Spent Fuel Pool

o      At 7:45AM on April 7, the temperature of the spent fuel pool: 82.4 degrees Fahrenheit.

  • Others

Our official sources are:

  • Office of The Prime Minister of Japan
  • Nuclear and Industrial Safety Agency (NISA)
  • Tokyo Electric Power Company (TEPCO) Press Releases
  • Ministry of Education, Culture, Sports, Science and Technology (MEXT)