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Saturday, June 4, 2011

TEPCO video: Steam and high rad levels in No. 1 plant

Tokyo Electric Power Company has released a video, taken June 3 by a robot during a survey inside No. 1 reactor building, showing steam rising around pipe penetrations. Video below courtesy TEPCO.


According to reports there are local radiation levels between 300 R/Hr and 400 R/Hr in the approximate vicinity of the video shown here.

TEPCO also released more photos from inside No. 1 plant, showing the new temporary pressure gauges installed to indicate pressure in the reactor vessel, and some workers in the area of the new gauges. Two pics below courtesy TEPCO.

5:50 AM Eastern Saturday June 4, 2011


  1. Can you identify (or did TEPCO?) the location of the pipe that's leaking steam? You say 'penetration' -- they're looking at a pipe that goes through the pressure vessel wall.

    Any idea if the steam leak is from a break in the pipe, or if the steam is coming through a leak, out around the pipe, from the gasket or seal or weld at the location where the pipe goes through the pressure vessel?

  2. This pipe is not penetrating the pressure vessel wall. This steam is thought to be coming either from the reactor building basement or else from the suppression pool directly; the pipe penetration you see in the video is in a floor.

  3. Thanks, that helps. Do they identify the location by _which_ floor, or anything else at all?

    Presumably they know where the robots are for each picture and video; is it disclosed anywhere?

    Sorry to bother you with these questions; I haven't found where Tepco made this info available.

  4. Ah, here's another mention with a bit more info, still second hand, from

    Saturday, June 4, 2011

    "Steam, high radiation detected at No.1 reactor
    The operator of the damaged Fukushima Daiichi nuclear plant says steam was observed coming out of the floor of the No.1 reactor building, and extremely high radiation was detected in the vicinity. Tokyo Electric Power Company inspected the inside of the No.1 reactor building on Friday with a remote-controlled robot.

    TEPCO said it found that steam was rising from a crevice in the floor, and that extremely high radiation of 3,000 to 4,000 millisieverts per hour (300 to 400 R/hour) was measured around the area. The radiation is believed to be the highest detected in the air at the plant. TEPCO says the steam is likely coming from water at a temperature of 50 degrees Celsius that has accumulated in the basement of the reactor building."

    That post says more info is available at:

  5. More details:


    "The utility said it took the reading near the floor at the southeast corner of the building. The steam appears to be entering from a leaking rubber gasket that is supposed to seal the area where the pipe comes up through the first floor. No damage to the pipe was found, Tepco said.

    The reactor's suppression chamber is under the building, and highly radioactive water generated from cooling the reactor is believed to have accumulated there, Tepco said, adding that the steam is probably coming from there."