Tuesday, July 5, 2011

Update on Steel Sheets on Reactor 3 Bldg Floor at #Fukushima I Nuke Plant: They Are to Block Radiation from Basement Water

It seems those steel sheets that have been laid down are to block the high radiation that may be coming from the water in the basement, according to Kyodo News Japanese.

It was indicated as much by a tweet on July 3 from a worker currently at Fukushima I Nuke Plant.

No information on how high the radiation of the contaminated water in the basement may be. 

The Reactor 3 used MOX-fuel, and the contaminated water that accumulated in the basement got there after it went over the melted (or partially melted) MOX-fuel. The temperature inside the Reactor Pressure Vessel remains high.

High radiation or not, TEPCO seems determined to start the injection of nitrogen into the Reactor 3 Containment Vessel by July 17, which is the deadline by which the step 1 in TEPCO's roadmap, "stable cooling" of the reactors is to be completed. The date has also been indicated by the government to be the day when the government will announce the "reduction" (believe it or not) of the planned evacuation zone.

Extend and pretend. And the bots and carbons alike will have to brave the unknown amount of high radiation at the plant so that the government can "extend and pretend".


Anonymous said...

A reduction of the zone would be reasonable, if they also extend it.

In all likelyhood, future airborne releases, post the establishment of loop cooing, will be so small as to be insignificant. Therefore, it makes sense to restore to use areas that have not been contaminated already.

On the other hand, the area should be extended in a northwesterly direction, to match the actual contamination pattern.

Net result? Reduction in area (good PR!), more contaminated land barred from use.

Now, will the Japanese gov't do this? Remains to be seen.

Hélios said...

Do steel sheets available against radiation ? Lead sheets would not be more efficient ?

Frenchy friendly

Anonymous said...

You only need to apply 1 cm thick lead sheet between the steel sheets to half the gamma radiation. But to achieve same with the steel only, you need a sheet that's 2.5 cm thick. So sandwich these two materials together and you get an effective shield to prevent the most harmful radiation. But the question is are they going to do when they couldn't admit at the beginning that all three reactors had gone in the full meltdown. I doubt that. A human life doesn't mean anything to them.

Cherie said...

High radiation of 100 mSV coming up through the floor?

a 4" cement floor with steel and iron is passing 100 mSV?

What's the radiation level in the basement water?
if concrete has a halving thickness of 2.5", then we may be
looking at 400mSV in the basement water.


can anyone read the floor thickness off the plans?

Anonymous said...

Let Jeffery Immelt (CEO of G.E.), get his ass over there, so he can be in front to place the steel sheets in front of reactor 3, after all 3 G.E. Engineers in the 1970's knew of problems with this BWR Nuclear Reactor G.E. design. What G.E. allowed with this design of the BWR Nuclear reactor was incompetence, and dereliction of duty, when they allowed this design (BWR, with these Cooling features and very little breachment with safety) to put into any BWR Nuclear reactor and especially one near the "ring of fire" area, with earthquake prone areas.

Bruce Hayden said...

The average person knows that lead is the best protection from radiation. The TEPCO/government response has been one fiasco after another. They should all be tried for 'crimes against humanity.'
If the Japanese government won't do it then take it to the ICC. This will never happen of course.
The msm is more concerned with the likes of Kadhafi. They refused the offer of help from the Russians due to their piss poor need to save face.
The biggest crime was in not letting the world know that three reactors were in full meltdown within the first few days. Millions of people are going to die an ugly death at an early age because of their lies and incompetence. I say let the TEPCO bigwigs install the steel plates until they reach their maximum lifetime dose.

arevamirpal::laprimavera said...

@Helios and others who commented "why not lead?": according to a person who used to work for a nuclear power plant, lead would be too soft to use for the work planned for that area. They doubled the steel sheets, and I hear they may use lead mat or sheet over the top.

@Cherie, steam coming from Reactor 1's basement water was 4 sieverts/hour, or 4000 millisieverts/hour. Reactor 3 may be hotter. MOX-fuel.

Anonymous said...

".. then we may be
looking at 400mSV in the basement water."

cobalt energies ?

If nitrogen is going to be injected, they must still think some rods aren't melted down. What is making them think that?
The one lone assembly handle in the SFP?

They might be finding the MOX assemblies are especially problematic, too hot/unpredictable, had to be submerged in water when shipped to Fukushima.

Anonymous said...

Remember this IR image ? ,


Anonymous said...

And this gamma image ? ,


So if Fukushima II ("Daini") has cobalt-60 in basement water, for whatever reason, then Fukushima I Daiichi will have it in the basement also.

".. it contains radioactive cobalt-60 which probably came from the rusty pipes .."

That's probably the reason for the steel plates on the floor.

"Greenpeace detected cobalt-60 in a park in Fukushima City."

Here's some irony for 'ya,

"In the end, however, we must face the brutal reality that no technological remedies can provide complete confidence that we are safe from radiological attack. Determined, malicious groups might still find a way to use radiological weapons or other means when their only goal is killing innocent people, and if they have no regard for their own lives. In the long run our greatest hope must lie in building a prosperous, free world where the conditions that breed such monsters have vanished from the earth."
And then TEPCO lit up its Inaction Dirty Bomb Fukushima.


Anonymous said...

But doesn't Cobalt 60 require shielding 1.5 meters thick, not just a few inches?

Isn't that why the dentist, radiotherapist goes and stands in the other room during your X-ray?

Anonymous said...

note this is for lead, not steel + concrete + water


Commonly Used Thicknesses
5 cm Thick - Cobalt 60

The steel plates might indicate emanation from the basement, or explosion debris/dust on the floor.

They might not know themselves as the robot's vacuuming didn't seem to lessen measured levels.

The red spots,
are the "max=1820". counts per minute?

Note that with the camera's angle of incidence, they are still getting max=1820 some distance from the camera into the building.

It may even be from the debris from outside the building that has been carried inside by workers.

You'll note TEPCO does not provide those details.

Anonymous said...

"But doesn't Cobalt 60 require shielding 1.5 meters thick, not just a few inches?"

.. and the appropriate answer to that is to ask Fukushima Daiini what shielding measures they are using after finding cobalt 60 in THEIR basement water.


joewein said...

They measured 1000 mSv/h near basement water before, thoughh I think that was unit 2, which is more contaminated than unit 3 (the second worst). They measured over 400 mSv/h near the stairs leading into the basement, near the water.

The MOX in unit 3 doesn't make that much difference, actually. Only a small portion of the fuel rods (6%?) are MOX rods and even in conventional enriched uranium oxide rods a significant proportion of the U238 turns into Pu239 during burn up. Expect as much as 0.8% Pu in non-MOX BWR fuel rods before refueling.

Also the upside of Pu239's long half life of > 24,000 years (compared to 2 years in Cs-134 and 30 years in Cs-137) is less radioactive decay. The alpha particles would never make it through the concrete floor, they get stopped by a sheet of paper (they're a worry primarily if alpha sources are inhaled/ingested). It's the gamma that would count at a distance. In any of the reactor blocks right now the gamma radiation from the cesium is the dominant form of radiation.

Post a Comment