Wednesday, November 16, 2011

#Fukushima I Nuke Plant: 1.3 SIEVERT/HR Inside Reactor 3 Bldg

where the carbon-based workers would have to go in to install the gas management system, which would filter the gas coming out of the Containment Vessel to capture radioactive materials and release it outside.

One minute of work at that location would get a carbon-based worker over 21 millisieverts radiation. One second 360 microsieverts.

As I said before, a futile window-dressing, as the CV have been breached somewhere already. It is absolutely crazy, bordering criminal, to send workers there for a cosmetic, token work.

First, as Mainichi Shinbun (11/16/2011) reports it:


TEPCO announced on November 16 that 1,300 millisieverts/hour [or 1.3 sievert/hour] radiation was measured in the northeast corner of the reactor building 1st floor of Reactor 3 at Fukushima I Nuclear Power Plant. It is the highest radiation level so far measured inside the Reactor 3 reactor building.


On November 14, a robot wiped off the water on the rail that is used to move the concrete door of the Containment Vessel [of Reactor3], and detected the radiation at 10 to 20 centimeters off the floor. The robot was sent in to prepare for the work to install the "gas management system" that would clean the gas inside the Containment Vessel and release the cleaned gas into the atmosphere. TEPCO's Matsumoto said, "It is possible the pressure inside the Containment Vessel rose after the accident and that radioactive materials leaked".


In the reactor building of Reactor 1, over 5,000 millisieverts/hour [or 5 sieverts/hour] radiation was measured in August.

Leak from the Containment Vessel "possible"? (Matsumoto is the master of understatement; he is good at presenting a ridiculous idea with straight face - like when he announced bath salt tracer.)

Back in April, New York Times quoted an anonymous Japanese nuclear industry insider saying there was a huge, vertical crack in the Containment Vessel of Reactor 3, and that the crack was getting wider. That reference was removed several days later after the article was published. (I copied what remained in the cache. I'm looking for it now.)

As to more than 5,000 millisievert/hour radiation in Reactor 1, we were never told how much "more than 5,000".

Now here's what TEPCO released to the press on November 16, 2011. The robot seems to be one of the Packbots. The radiation levels in the area where 1.3 sievert/hour radiation was detected are universally high, as you see in the page 1 of the handout below:


Anonymous said...

Interesting corrosion pattern.

Atomfritz said...

If there was 1.3 sievert in a height of 20 cm, this means that the feet of the carbon-based robots will be in an environment of about 3 to 4 sieverts.

Expect some radioactive burns on the feet of these "robots", and soon leukemia/bone marrow cancer, if they don't agree to have their legs amputated immediately after the work.

Atomfritz said...

Ragarding the crack:

Such containment cracks apparently seem more common than we'd like.
Just recently such a containment crack has been discovered by chance at the infamous Davis Besse NPP in the course of the replacement of the already-replaced reactor head that got rusted through again. (see here: )

Could this crack possibly be the the reason for the mysterious black and white steaming of reactor #3?

Anonymous said...

From your link, Atomfritz,

"Workers used hydro-demolition to cut a 33 foot by 22 foot hole "

What the hell is hydro-demolition? High pressure water jets?

"The vertical crack runs as much as 30 feet along rebar "

Speaks of significant vibration or truly faulty concrete.

Atomfritz said...

@ anon 7:19

I suppose it was done with water jet cutting.
More info here:

Possible reason for containment cracking could be just normal operation. Inner side of the containment is heated to about 350 Celsius, making the concrete expand thermally.

At Fukushima we can be quite sure that it got way hotter than the normal operating temperature, stressing the concrete even more.

It's the same principle as pouring boiling water into a drinking glass, making it crack because the outer side is still cold and contracted while the inner side expands quickly.

Anonymous said...

Atomfritz the article about the Davis-Besse plant describes a crack in the containment building. The crack that the New York Times had reported (and then retracted) at Fukushima #3 was in the containment vessel.

There is a gigantic difference between a containment building, and a containment vessel. The building, which is quite large, holds a vessel, which is actually quite small.

A crack in a containment building is not a particularly big deal. A crack in a containment vessel is a potential catastrophe. Please learn the difference between a containment building and a containment vessel.

Anonymous said...

Looking through Henry Petroski's book "To Engineer is Human",
Petroski begins to mention nuclear reactor pressure vessel metals and neutron irradiation on page 115.

The metal "reference temperature" is raised over time by neutron irradiation.

"Thus, should an accident [any accident] occur that would trigger the emergency core cooling systems to cool the pressurized vessel too quickly -- toward a raised reference temperature -- any preexisting cracks might grow quite rapidly."

If a reactor's Emergency Core Cooling System has been activated, for any reason, the reactor pressure vessel is much more likely to have been compromised.

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