Jeffrey LewisFEPC Info Sheet 4/13

We have some interesting comments on yesterday’s thread about the wonders of the INES.  I wonder Fukushima results in a fundamental reform of the scale, with the IAEA taking on a role in vetting how states rank their nuclear disasters. Olli Heinonen thinks so, or at least that is how Pete Spots paraphrases him in the Christian Science Monitor.

Anyway, your daily fix from our friends at FEPC 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 9:30AM (EST), April 13, 2011

  • 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 at the screen of Unit 2 at 1:50PM on April 12  (a) Sampled at south side discharge point at 2:00PM on April 12  (b) Maximum Permissible Water Concentration (c) a / c b / c
I-131

(8 days)

1.0 x 102 1.3 x 100 4.0 x 10-2 2,500 33
Cs-134

(2 years)

8.3 x 101 1.4 x 100 6.0 x 10-2 1,400 23
Cs-137

(30 years)

8.4 x 101 1.4 x 100 9.0 x 10-2 930 16
    • At 4:00PM (JST) on April 13, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 76 micro Sv/hour.
    • At 4:00PM on April 13, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 39.2 micro Sv/hour.
    • Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 1:00PM on April 13 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) 0.420 -0.016 -0.023 0.003 0.019
4/13

12:00PM

4/13

12:00PM

4/13

12:10PM

4/13

1:00PM

4/13

1:00PM

pressure inside the primary containment vessel (absolute pressure, MPaabs) 0.190 0.095 0.1036
4/13

12:00PM

4/13

12:00PM

4/13

12:10PM

water level inside the reactor core (meter) *1 -1.6 -1.5 -1.75 +1.59 +2.365
4/13

12:00PM

4/13

12:00PM

4/13

12:10PM

4/13

1:00PM

4/13

1:00PM

temperature of the reactor vessel measured at the water supply nozzle (degrees Fahrenheit) 400.1

*2

332.4 198.0

*2

4/13

12:00PM

4/13

12:00PM

4/13

12:10PM

temperature of the spent fuel pool (degrees Fahrenheit) 113 95.2 73.4
4/13

12:00PM

4/13

1:00PM

4/13

1:00PM

the temperature directly above the spent fuel pool by thermography measurement (degrees Fahrenheit) 78.8 138.2 98.6
4/12

7:50AM

4/12

7:50AM

4/12

7:50AM

temperature directly above the primary containment vessel by thermography measurement (degrees Fahrenheit) 62.6 69.8
4/12

7:50AM

4/12

7:50AM

temperature directly above the second containment building  by thermography measurement (degrees Fahrenheit) 82.4
4/12

7:50AM

Amount of water in total shot/injected to the spent fuel storage pool (tons) 90 359 – 374 5,238 1,816
as of 4/13

5:00PM

as of 4/13

5:00PM

as of 4/13

5:00PM

as of 4/13

5:00PM

*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
    • As of 12:00PM on April 13, injection of nitrogen gas into the primary containment vessel to prevent an explosion by accumulated hydrogen gas continues.
    • As of 12:00PM on April 13, the injection of freshwater into the reactor core continues.
  • Fukushima Daiichi Unit 2 reactor
    • At 7:35PM on April 12, transferring of the accumulated water at the trench (concrete tunnel which houses pipes and cables) outside the turbine building to the condenser commenced.
    • At 1:15PM on April 13, TEPCO began to inject freshwater into the spent fuel pool, until 2:55PM.
    • As of 12:00PM on April 13, the injection of freshwater into the reactor core continues.
  • Fukushima Daiichi Unit 3 reactor
    • As of 12:00PM on April 13, the injection of freshwater into the reactor core continues.
  • Fukushima Daiichi Unit 4 reactor
    • At 0:30AM on April 13, TEPCO began to shoot freshwater aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete, until 6:57PM (approximately 195 tons in total).
  • Fukushima Daiichi Common Spent Fuel Pool
    • At 8:00AM on April 13, the temperature of the spent fuel pool: 84.2 degrees Fahrenheit.
  • Others
    • At 1:00PM on April 12 and at 10:00AM on April 13, TEPCO installed steel plates at the ocean side of the screen device of Unit 2 in order to contain the spread of discharged radioactive water.
    • At 1:50PM on April 13, TEPCO installed a silt fence at the ocean side of the screen device of Unit 3 and 4 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)

Comments

  1. Christian (History)

    There have been some comments on the internet about the radiation level at Reactor 1 exceeding 100Sv/h. At first I thought this was speculation, but I found the source data and it appears this is the reading in the drywell. Does anyone know the significance of this? Here is the link (there’s an option partway down to show everything in English):

    http://atmc.jp/
    http://atmc.jp/plant/rad/?n=1

  2. bks (History)

    Who cares about the INES scale? They caught more radioactive fish today. Please get Fukushima under control first, then worry about reforming the metric.

    –bks

    • joshua (History)

      Not everyone can be a first responder. No time like the present to rethink INES, which hasn’t lived up to its aspirations to be a “prompt” and “consistent” communication tool.

  3. Nick (History)

    I had always understood that if the rods were uncovered for several hours, they would start to melt. The rods have now been uncovered for over a month. Shouldn’t they have had significant melting by now? Also, I had read that melted fuel would burn through the vessel in a matter of days. Is that correct?

    • John Schilling (History)

      If the rods had been uncovered for several hours in the immediate aftermath, they would have started to melt. In fact, it is highly likely that this happened and the only question is the degree of melting. However, heat generation in the core is now only one-tenth what it was at the time of primary cooling failure, so it is much less likely that exposed rods will melt now.

      As for melted fuel burning through the vessel, the primary containment (~10 cm of steel) would fail fairly quickly once cooling was lost, and the secondary containment (several meters of reinforced concrete) is not supposed to fail ever. Unfortunately, Fukushima is a 1st-generation BWR, and more sophisticated analysis by later generations of nuclear engineers suggests “not supposed to happpen ever” is roughly a 50/50 proposition in the event of a typical meltdown.

      In a matter of days, yes, and again far more likely at the outset of the accident than now. So long as there is still water at the bottom of the core, we should be safe in that respect. Down side of that is there are clearly cracks in the plumbing, so some of the water introduced to prevent a “China syndrome” will continue leak out, carrying dissolved radioactives. Slow and steady leak, or small chance of catastrophic failure – pick your poison.

  4. bks (History)

    What’s this all about?

    TOKYO, April 14 (Xinhua) — The radiation level of the groundwater had increased 10 fold in one week at the troubled Fukushima No. 1 nuclear power plant, Kyodo News reported Thursday, citing operator sources.

    Earlier on Thursday, the country’s nuclear safety agency said that the level of contaminated water in its underground trench turned out to be rising again.

    http://news.xinhuanet.com/english2010/world/2011-04/14/c_13829478.htm

    –bks

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