Jeffrey LewisTEPCO Info & Thermographs

TEPCO has released another information update.  Three workers were exposed to a doses exceeding 170 mSv.

From a wonky perspective, the SDF is releasing “thermographs” of the reactors — infrared images that show the heat from the reactor vessels and the spent fuel ponds. The SDF website has a full set of images from March 20, 23 and 24. They aren’t quite as high-res as the ones that aired on NHK (see the top of this post, via The Big Dustup), but the time series data is nice.

Full-text and images after the jump.

TEPCO Earthquake Information Update on March 24: Fukushima-Daiichi Status

(1) Worker received high dose, 2 hospitalized

On March 24th, it was confirmed that 3 contract workers laying cables in the 1st floor and the underground floor of turbine building were exposed to the radiation dose of more than 170 mSv.

2 of them were confirmed that their leg skin was contaminated. Although they were decontaminated, it is judged that there is possibility of beta ray burn injury, they were transferred to Fukushima Medical University Hospital. After medical examination at the hospital, they will be transferred to National Institute of Radiological Sciences in Chiba Prefecture on March 25 and stay around four days for medical check.

Confirmed radiation dose of each workers are:

Worker (A: 30’s)  180.07 mSv
Worker (B; 20’s)  179.37 mSv
Worker (C: 30’s)  173.00 mSv

Planned dose for this work was 20 mSv, and set alarm at 20 mSv. Workers wore proper personal dosimeter, but they accidentally soaked their foot in the contaminated water, depth of which was 15 cm. The work site was dark because of power outage.

Use of long boots is determined considering the work environment such as radioactive control and workability, in the case of the work using water. According to the information on the site of the previous day (March 23), there was not much water at the site of the work, therefore high boots had not been prepared.

The radiation dose in the B-1 floor of turbine building was 400mSV at water surface and 200mSV in the Air.

As of 6:30 am, March 24, 17 workers exceeded 100 mSv in Fukushima-Daiichi NPS.

(2) Result of thermograph by SDF

Self Defense Force takes thermographs over Fukushima-Daiichi units 1-4 on March 20, 23 and 24.

Below pictures are results of March 24 flight. You can find the rest of the results on the Ministry of Defense Web site (see bottom of this e-mail).

•           Date/Time: March 24,2011 06:54-07:26
•           Weather: Cloudy
•           Temperature: 1C (Soma City at 07:00)
•           Altitude: 3000ft (900m)
•           Chopper: CH-47 (SDF)
•           Camera: NEC/Avio Infrared thermography
•           Shooting Range: 87m x 65m (@3000ft)
•           Temp. Range: 0 – 500 C

Note: The JSDF has made available thermographs from March 20, March 23 and March 24. The camera is an NEC/Avio product.

First Putzmeister, now NEC/Avio.  There may be a budding market for product placement in large-scale disasters.  “This futile effort to flood a molten reactor core is brought to you by Pocari Sweat, the official sports drink of the 2011 Tohoku Earthquake.”



  1. bks (History)

    How did radiation increase from 20 to 200 mSv in 24 hours?


  2. b (History)

    No. 4 has obviously seen a big explosion which ripped of the concrete walls and the roof of building.

    This likely came from hydrogen which again must have come from spent fuel at high temperature reacting with steaming water. The load in the no.4 SFP is the highest in the complex and the fuel there is the most fresh one.

    Then why is the spent fuel pond no.4 in those pictures nearly cool?

    This doesn’t compute. Any ideas?

    • gbettanini (History)

      No idea,
      another thing that doesn’t compute is a ratio of around 10 between I-131 and Cs-137 in the soil/vegetables contamination, this is a typical ratio for the radioactive release of core fuel (and not 4 months old spent fuel), maybe they are venting the Primary Containment of some reactor or there is a PCV breach, possibly in n.2 reactor.

      So maybe the spent fuel pond’s radioactive releases are only marginal in front of total releases that seems to be in the range of the PBq’s.

    • gbettanini (History)

      Ok, while i was writing NHK published the possible answer:

      “Japan’s nuclear safety agency says it is highly likely that the Number 3 reactor of the troubled Fukushima Daiichi nuclear power plant has been damaged, leading to the leak of high levels of radiation.”

  3. bks (History)

    What is the procedure for cleaning up a million liters of seawater that measures 4 million becquerels per cc?


    • FSB (History)

      Oh don’t worry — nuclear energy is perfectly safe. The nuclear industry will take good care of you.

      And we really need nuclear to supply, like, 10% of the power mix at huge government subsidies or else we will die.

      When nuclear can compete with other power sources without government intervention and bailouts (incl. cleanup bailouts) then we should definitely consider it.

    • ikje (History)



      dilute it. That is how it is tradionally done during the last 80 years.

  4. rwendland (History)

    These infra-red measurements would need considerable analysis to map to an understanding of what is happening in the containment. They are at huge variance with the internal measurements offered by NISA. There must be concrete and random bits of metal in the way.

    Compared to the NISA numbers at a similar time, 05:00 March 24th, 2011, and assuming PCV above means Position on the Containment of the RPV:

    Unit 1 RPV: Infra-red PCV: 17 ℃, Temperature at the bottom head of RPV: 229 ℃

    Unit 2: Infra-red roof temp: ~10℃, Spent Fuel Pool Water Temperature: 52 ℃

    Unit 3 RPV: Infra-red PCV: 11 ℃, Temperature at the bottom head of RPV: 185.4℃

    Unit 2 SNF pool: Infra-red highest temp spot: ~15℃, Spent Fuel Pool Water Temperature: 100℃

  5. bks (History)

    When Steven Chu, pro-nuclear Secretary of Energy and awardee of the Nobel Prize for Physics was interviewed on CNN on Sunday he *corrected* the interviewer when she said that reactor 3 was the biggest problem. He pointed to reactor 2.


    • Jeffrey (History)

      Chu was referring to the risk of a containment breach.

      There is a separate issue related to the spent nuclear fuel in the cooling pools, which is largely focused on Unit 3 (which was hot in the image) and Unit 4 (which was not, but which has a full load of both fresh and spent fuel, so represents a worst-case danger).

    • Jeffrey (History)

      NISA is now saying they think the radiation is coming from Unit 3, but they don’t know if it is a containment breach or an incident in the spent fuel pool.

      (The SNF might just melt, rather than catching on fire.)

    • rwendland (History)

      Jeffrey, re Unit 4 SNF pool – NISA reported a temp reading of 100℃ there at 05:00 March 24th, 2011; though later at 10:00 that beacme “Indication failure”, so maybe that 100℃ wasn’r reliable.

      I made a typo above, should have been Unit 4, not 2, in:

      Unit 4 SNF pool: Infra-red highest temp spot: ~15℃, Spent Fuel Pool Water Temperature: 100℃

  6. conpie (History)

    About “temperature” measurements, take them with a grain of salt, since it’s not kinetic temperature but radiative temperature. the signal is a mixture of kinetic temperature and emissivity (specific to the material).
    So, as mentionned there is no straightforward path between temperature measurements posted by TEPCO and infrared imagery.
    Very interesting though, thanks for the finding!