Monday, May 21, 2012

#Fukushima I Nuke Plant Reactor 1 Containment Vessel May Have Only 40 Centimeters of Water, Government Researchers at JNES Say

Move over, Reactor 2 (which has 60 centimeters of water)...

Tokyo Shinbun reports that the Japan Nuclear Energy Safety Organization under the Ministry of Economy, Trade and Industry analyzed the parameters of Reactor 1 at Fukushima I Nuclear Power Plant, and concluded that there may be only 40 centimeters of water retained inside the Containment Vessel.

Tokyo Shinbun's graphics shows the cooling water leaking from a downcomer.

The fuel debris (corium) is estimated to have eaten into the concrete floor of the Containment Vessel in Reactor 1, as announced in November last year. TEPCO's estimate is about 65 centimeters, and the estimate by the Institute of Applied Energy is as much as 2 meters.

From Tokyo Shinbun (5/22/2012):


Analysis by the Japan Nuclear Energy Safety Organization (JNES) has revealed the possibility that the water inside the Containment Vessel of Reactor 1 may be only 40-centimeter deep, despite 6 tonnes/hour water being injected [into the Reactor Pressure Vessel]. The water level inside the Reactor 2 Containment Vessel has been measured by an actual survey to be about 60-centimeter deep. It shows how severe the damages to the Containment Vessels have really been.


In the analysis, JNES studied the relationship between the amount of water injected, the amount of nitrogen gas injected into the Containment Vessel and change in pressure levels inside the Containment Vessel to come up with the locations and the extent of damage that would explain the change in pressure levels well.


JNES has concluded that:

  • There is a hole several centimeters in diameter on the pipe that connects the Containment Vessel and the Suppression Chamber;

  • The location of the hole is about 40 centimeters from the concrete floor of the Containment Vessel.

  • The injected water is leaking from the hole in great quantities.

  • There is no water [in the Containment Vessel] above the hole.


The leaked water is considered to be flowing down to the basement of the Reactor building, and then into the adjacent turbine building through the pipes and cable ducts. TEPCO has estimated the water level of the Reactor 1 Containment Vessel to be about 1.8 meters, but the JNES analysis shows it is far less.


The Containment Vessel is about 3 centimeters thick. However, the thickness of the 1.75-meter diameter pipe that may have a hole is only 7.5 millimeters thick, or only a quarter of the thickness of the Containment Vessel. Experts have pointed out that the pipe is structurally weak.


There is also a fear that the fuel debris [corium] may not be completely submerged in water. But the JNES researchers say, "The temperature inside the Containment Vessel is not that high, at 30 degrees Celsius. The fuel debris is considered to be submerged and cooled."


In order to decommission the reactors, it is necessary to repair the damage(s) on the Containment Vessels so that the Reactor Pressure Vessel can be entombed with water. The researchers say, "The result of the analysis is useful in identifying the damage. We should also consider the actual survey using a camera."

As I reported here in December last year, Professor Takashi Tsuruda of Akita Prefectural University, a combustion expert, thinks the Reactor 1 Suppression Chamber was damaged in the explosion.


Anonymous said...

So the leak is on the top of the downcomer ? Is it possible that something from the explosion fell onto the downcomer ?

Anonymous said...

After over a year of NOT covering Reactor #1, now comes some charade news of little water. Take a good look at the high resolution photo just after the explosion, you will see the reactor is NOT there anymore!. So either the Scada controller is feeding bogus data or Tepco is feeding bogus data.
Seal this and move on to Reactor #4.

Anonymous said...

Reactor 4? Hell no that's old news. Gundersen warns us it's Reactor 3!

Anonymous said...

How long will they have to inject nitrogen gas into the reactor?

How much nitrogen do they inject and is there enough nitrogen to do this for a long time?

arevamirpal::laprimavera said...

They've been doing the nitrogen injection into the Reactor 1 CV since April last year.

Anonymous said...

So if they use nitrogen to cool the reactors and lithium burns in nitrogen, then what would they use to cool a lithium reactor?

Anonymous said...

"3. First hadronic lithium reactor: The engineering realization of the first lithium reaction, Eq. (7.34), is essentially the same as that for the oxygen reactor, the only difference being that the vessel is filled up with a 50-50 mixture of hydrogen and helium gases also at 3,000 psi. The mixture is also recirculated through a 50 Kw electric arc that creates magnecules HxHe. The trigger can also be given by a high voltage pulse DC current or impulse pressure or other mechanism.
4. Second hadronic lithium reactor: The engineering realization of the second lithium reaction, Eq. (7.35), is more complex than the preceding one because of the need of lithium nuclei and a beam of protons with opposite polarization as a necessary condition to avoid a random reactions as occurring in "cold fusions". Current technology allows a variety of engineering realization of the needed polarization represented in Figure 7.16 where a proton beam with down polarization enters a chamber of lithium with up polarization, both polarizations being realized via magnetic fields. The efficiency of the hadronic reactor is then dependent on the geometry of both the proton beam and the lithium chamber plus an adequate trigger the author has not been authorized to disclose here at this time."

Anonymous said...

Nitrogen gas injection is to prevent hydrogen explosions, in case of Fukushima reactors.

Anonymous said...

Then there are 40cm of water over the bottom of the containment vessel, but since the fuel is either 65 or 2 meters into the concrete it means the fuel is covered by around 1~2.4 meters of water?

Anonymous said...


"How much nitrogen do they inject and is there enough nitrogen to do this for a long time?"

Yes, there is... 75% of dry air is made up of nitrogen... so I would say they could keep on injecting for a couple billion years at least... :-)


TechDud said...

I wonder if they bring in bottles or dewars, or if it is generated on-site.

Thank you, again Admin. for faithfully relaying that which others fear to say.

Chibaguy said...

I wonder when the MSM will actually pick this up. I am not really into politics as I see both parties in bed with each other. POTUS Obama is wrong. He maybe should read this blog everyday.

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