Over 1000 Sieverts Per Hour – Fukushima Reactor 2 Radiation

Over 1000 Sieverts Per Hour – Fukushima Reactor 2 Radiation

Radiation levels in the Fukushima nuclear reactor 2 containment vessel spike to 73 SV/HR and are calculated to be over 1000 SV/HRr at the source of the exposed fuel.

TEPCO announced plans to perform an endoscope operation inside the Fukushima Reactor 2 on March 26th during which they discovered the water level had dropped to only 60 centimeters from the bottom

The operation continued into its second day on March 27th and the data released is absolutely shocking during which radiation levels in the reactor’s containment vessels were measured at 73 sieverts per hour.

Even more alarming is TEPCO is radiation levels inside the actual reactor are so high that TEPCO was prevented from even attempting to get video of the the exposed nuclear fuel inside.

According to a Fukushima worker, TEPCO calculates the radiation being emitted from the exposed fuel to be far in excess of 1000 sieverts per hour that the endoscope is rated to handle.

If there is any good news in this it is, according to TEPCO, while the level inside the reactor is extremely high it is resulting in an atmospheric dose of only 6.1 Sieverts per hour.

That shouldn’t be taken lightly however, that just means instead of being lethal in just 15 seconds near the pedestal or 2 to 3 minutes where the 73 sieverts per hour, it would take an hour to kill be lethal to 100% of the population in the location the measured the atmospheric dose.

Prior to the endoscopy operation, TEPCO had estimated that the water levels inside the reactor to be 10 feet deep.

With water levels now being less than 2 feet from the bottom the Fukushima worker reports that TEPCO’s plan to remove the nuclear fuel from the reactors will now take longer than the 10 years originally planned.

73Sv/h in container vessel

During the endoscope operation of 3/26/2012, Tepco measured the radiation level of inside of container vessel. Tepco published the data the next day, 3/27/2012.

It was measured at 8 points, 50~100cm away from the wall.
The highest reading was 73Sv/h.(100,000 times higher than the radiation level of the container vessel in periodic checkup) Other readings were 31.1~57.4 Sv/h.


In this level of radiation, human starts vomiting within a minute and dies within 8 minutes. It is impossible to have human work inside of container vessel.

Actually, Tepco did not intend to watch the fuel debris in this endoscope operation. Tepco is assuming that the fuel is in pedestal, which is separated from where they checked with endoscope this time with concrete wall. (Like this picture below.)

To see where Tepco assumes the fuel debris is, they have to put the camera under the pressure vessel, surrounded by the concrete of pedestal. About this potential attempt, [an] actual Fukushima worker tweeted […].

(@Happy11311) March 27, 2012The highest reading of 73 Sv/h was lower than I thought, but no one can get close to there. Probably it is higher than 1000Sv/h inside or in front of the entrance of the pedestal. The endoscope used this time can’t resist the radiation of higher than 1000Sv/h so it would be over scale

(@Happy11311) March 27, 2012 – The fuel debris has not been checked yet, but this operation made it clear that it would take considerable amount of time to fill container vessel with water as Tepco is planning, or it would be simply impossible. and they are planning to take out the fuel in 10 years but it would take way more than 10 years. I don’t know how long it takes.

The Fukushima Diary reports further:

Water level was only 60cm from the bottom in reactor 2

Following up this article… The second endoscope operation is planned for 3/26 and 27

Tepco announced the endoscope (20m long) operation on 3/26/2012.

They found out the water level was only 60cm above from the bottom of container vessel in reactor2. Probably the bottom of container vessel is damaged.

The atmospheric temperature was 44.5~44.9℃, temperature of the water was 48.5~50.0℃. Atmospheric dose was 6.1 Sv/h.

The exposure dose of the workers were 5.29mSv/ man・day.


Graphs of Reactor 2Radiation Readings



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