Ben Quinn in the Guardian reports that TEPCO has stopped the leak of radioactive seawater.

Today’s FEPC info sheet indicates that TEPCO is installing some sort of silt barrier to contain the leakage of radioactive water.  Cryptome has some really amazing high-resolution pictures (1|2), including the one atop this post.

Full text of your daily FEPC info sheet after the jump.

Update to Information Sheet Regarding the Tohoku Earthquake

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

As of 11:30AM (EST), April 6, 2011

  • Radiation Levels

o      On April 6, TEPCO announced that plutonium 238, 239 and 240 were detected in the soil sampled on March 25 and 28 at Fukushima Daiichi Nuclear Power Station. Concentration of detected plutonium 238, 239 and 240 are the same level of the fallout observed in Japan at the atmospheric nuclear tests in the past, but TEPCO assumes the detected plutonium are attributed to the Fukushima Daiichi Nuclear Power Station, considering the isotope ratio of Plutonium 238 to 239 and 240.

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 of Fukushima Daiichi Nuclear Station was as follows:

 

Nuclides 

(half-life)

Concentration (Unit : Bq/cm3) Ratio
Sampled at 8:00AM on April 5  (a) Maximum Permissible Water Concentration (b) a / b
I-131 

(8 days)

1.1 x 104 4.0 x 10-2 280,000
Cs-134 

(2 years)

5.5 x 103 6.0 x 10-2 92,000
Cs-137 

(30 years)

5.5 x 103 9.0 x 10-2 61,000

 

o      The level of concentration of radioactive nuclide I-131 (1.1 x 101 Bq/cm3) from the seawater sampled near the seawater discharge point of Fukushima Daiichi Nuclear Station at 2:10PM (JST) on April 5 was approximately 280 times higher than the maximum permissible water concentration (4.0 x 10-2 Bq/cm3)  set by the government.

o      At 7:00PM on April 6, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 82.5 micro Sv/hour.

o      Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 7:00PM on April 6 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.

  • Fukushima Daiichi Unit 1 reactor

o      On April 6, TEPCO announced that it will start the injection of nitrogen gas into the primary containment vessel at 10:30PM to prevent an explosion by accumulated hydrogen gas.

o      At 7:30AM on April 6, the temperature directly above the spent fuel pool by thermography measurement: 75.2 degrees Fahrenheit.

o      At 7:30AM on April 6, the temperature directly above the primary containment vessel by thermography measurement: 84.2 degrees Fahrenheit.

o      At 12:00PM on April 6, pressure inside the reactor core: 0.313MPa.

o      At 12:00PM on April 6, water level inside the reactor core: 1.65 meters below the top of the fuel rods.

o      At 12:00PM on April 6, pressure inside the primary containment vessel: 0.15MPaabs.

o      At 12:00PM on April 6, the temperature of the reactor vessel measured at the water supply nozzle: 417.2 degrees Fahrenheit.

o      As of 2:30PM on April 6, the injection of freshwater into the reactor core continues.

  • Fukushima Daiichi Unit 2 reactor

o      At 5:38AM on April 6, TEPCO confirmed the termination of water leakage into the ocean through a crack on the lateral surface of the pit (a vertical portion of an underground structure for housing electric cables) near the seawater intake.

o      At 7:30AM on April 6, the temperature directly above the second containment building by thermography measurement: 89.6 degrees Fahrenheit.

o      At 12:00PM on April 6, pressure inside the reactor core: -0.016MPa.

o      At 12:00PM on April 6, water level inside the reactor core: 1.5 meters below the top of the fuel rods.

o      At 12:00PM on April 6, pressure inside the primary containment vessel: 0.10MPaabs.

o      At 12:00PM on April 6, the temperature of the reactor vessel measured at the water supply nozzle: 288.5 degrees Fahrenheit.

o      At 12:00PM on April 6, the temperature of the spent fuel pool: 123.8 degrees Fahrenheit.

o      As of 2:30PM on April 6, the injection of freshwater into the reactor core continues.

  • Fukushima Daiichi Unit 3 reactor

o      At 7:30AM on April 6, the temperature directly above the spent fuel pool by thermography measurement: 140 degrees Fahrenheit.

o      At 7:30AM on April 6, the temperature directly above the primary containment vessel by thermography measurement: 89.6 degrees Fahrenheit.

o      At 12:00PM on April 6, pressure inside the reactor core: 0.005MPa.

o      At 2:00PM on April 6, water level inside the reactor core: 1.8 meters below the top of the fuel rods.

o      At 12:00PM on April 6, pressure inside the primary containment vessel: 0.1069MPaabs.

o      At 12:00PM on April 6, the temperature of the reactor vessel measured at the water supply nozzle: 173.8 degrees Fahrenheit. (This figure is under investigation.)

o      As of 2:30PM on April 6, the injection of freshwater into the reactor core continues.

  • Fukushima Daiichi Unit 4 reactor

o      At 7:30AM on April 6, the temperature directly above the spent fuel pool by thermography measurement: 134.6 degrees Fahrenheit.

  • Fukushima Daiichi Unit 5 reactor

o      At 1:00PM on April 6, the temperature of the spent fuel pool: 95.4 degrees Fahrenheit.

  • Fukushima Daiichi Unit 6 reactor

o      At 1:00PM on April 6, the temperature of the spent fuel pool: 85.1 degrees Fahrenheit.

  • Fukushima Daiichi Common Spent Fuel Pool

o      At 8:00AM on April 6, the temperature of the spent fuel pool: 80.6 degrees Fahrenheit.

  • Others

o      At 3:00PM on April 5, TEPCO began to install the components of a silt barrier near the south sea wall of Fukushima Daiichi Nuclear Power Station in order to contain the spread of discharged radioactive water.

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)