Holes discovered (admitted to) in Reactors 1,2,3 pressure vessels

[flamingdem]

From Asahi Shinbun news about one hour ago (3:00PM JST 3/28/2011).

In the Reactors 1, 2, and 3, the water level within the Pressure Vessels are not rising as much as desired. TEPCO admitted in the March 28 press conference that the reason why the Pressure Vessels haven't been filled with water was "probably a hole near the bottom, that's the image we have". Asked why there was a hole, TEPCO answered they did not know.

The Reactor Pressure Vessels (RPVs) are the most important of the 5-layer protection against radiation leak (other 4 are the fuel pellets, cladding of fuel rods, Container Vessels, and the Reactor buildings). The RPVs at Fukushima I Nuclear Power Plant is made of 16-centimeter thick steel, and it has an outlet at the bottom to insert measuring instruments. It is possible that the leak is from that area.

TEPCO also admitted to the possibility of the exposed nuclear fuel rods overheating and damaging the RPVs. According to the nuclear experts, if the fuel rods get damaged and start to melt, it will fall to the bottom of the RPVs and settle. It then becomes harder to cool with water effectively, because the surface area is smaller. It is possible that the melted fuel rods melted the wall of the RPVs with high temperature and created a hole.

On the other hand, TEPCO said it didn't think the RPVs are completely broken, because the pressures inside the RPVs were higher than the atmosphere. "It is not like Chernobyl where the RPV exploded and the fuels were outside the RPV." TEPCO continued to believe in the integrity of the RPVs.

[OKIsItJustMe]

1. I don’t know why people haven’t commented on this remark by JAIF

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=284140&mesg_id=284140

• Progress of the work to recover injection function
  Water injection to the reactor pressure vessel by temporally pumps were switched from seawater to freshwater at unit-1, 2 and 3, since adverse effect such as erosion is concerned. High radiation makes difficult the work to restore originally installed pumps for injection. (3 workers were sent to the hospital after heavily exposed on March 24 and discharged on March 28.)
• Function of containing radioactive material inside the containment vessel
  It is presumed that radioactive material inside the reactor vessel would have leaked outside the containment vessel at unit-1, 2 and unit-3, based on the investigation of the water sampled at turbine building.
• Cooling the spent fuel pool
  Steam like substance rose from the reactor building at unit 1, 2, 3 and 4 is being observed. Operation of spraying water to the spent fuel pool is being conducted.

[flamingdem]

2. It's the indirect language, you don't know which containment vessel

so when it's written as hole in the RPV (or whatever initials we know stands for the inner containment) then it's much more certain.

I agree that a lot of material gets put out by them and doesn't really get parsed until the media simplifies.

[OKIsItJustMe]

3. I've quoted this multiple times

But no one seems to have noticed. If, "radioactive material inside the reactor vessel would have leaked outside the containment vessel at unit-1, 2 and unit-3," that implies leaks to me.

They've been listing the RPV integrity for all 3 units as “Unknown” for some time now.

[intaglio]

5. According to the status report of 28 March

Damage and leakage suspected (but not confirmed) from the containment vessel. Please check the link given earlier.

[Throckmorton]

4. Lets not forget Rod Drive

Besides the "outlet at the bottom to insert measuring instruments", the control blade drive motor extension shafts exit the pressure vessel out the bottom.

I suspect that this is a more likely place for the reactor vessel to fail.

Gravity is not your friend in a GE-3 reactor, as the control blades enter the bottom of the core, and must be driven in. In PWR's, the rods go in from the top, and fall in under the force of gravity.