Thursday, April 12, 2012

(For Record) #Fukushima I Nuke Plant Reactor 4 Spent Fuel Pool Supporting Structure

From TEPCO's handout for the press on July 30, 2011:

The claim by some experts that only the steel posts are propping up the pool is not true.


Anonymous said...

The fuel pool is still weak. Also the added weight of all that concrete 50 feet in the air makes it unstable in a big quake. The building was not designed to carry a room full of concrete. Concrete is only supporting half the pool, also the sides can crack. If the pool goes dry, it will burn, no one can then work there, and all the fuel pools at Fukushima will burn. "Fukushima Burning" would be the same as 85 Chernobyls and could shut down a country for generations. Do NOT start any more nuclear plants in Japan and shut all of them down globally.

Anonymous said...

Just like to thank the workers who are risking their lives to do this work.

Anon 12.49
"Do NOT start any more nuclear plants in Japan and shut all of them down globally."

I very much agree with that statement after looking at these photos.

Anonymous said...

Who decided what was (and wasn't) needed? Is it enough? Who designed it? Who decided which corners to cut in order to keep TEPCO's costs down? Who built it?

So many questions. Who can you trust?

The only responsible approach in a situation as vitally important as this is to over-engineer everything. This is not the place for penny pinching or cost benefit analysis.

If a large asteroid were on a collision course with Earth, would we be not be doing everything in our collective power to prevent the collision? This is not the time to give any measure of concern for the financial viability of a corporation, industry or nation. TEPCO should not be involved in the spending decisions, and their financial status should be of no concern to the engineers needed to solve this problem.

Japan government must step up with whatever resources the engineering community believes is necessary to safeguard the country and the world from a repeat performance.

And the Japan government should completely insulate those engineers permanently from any retribution or consequences that their decisions might have on their future careers and earning capacity in or out of the nuclear industry.

Foreign countries should pressure Japan government to remove TEPCO from decision making, put competent independent engineers in charge of securing the site against further damage, and give them everything they ask for.

Do it now please. The world cannot wait.

Anonymous said...

competent independent engineers?

Where do you find them?

Anonymous said...

that was x equakes & y bodies ago. i think TEPCO did a good job on this one & prolonged the collapse. 4 probably should have fallen last summer.

Anonymous said...

Does ex-skf have a "mission statement" or written mandate on its outlook, purpose, objectives, etc.

Does the site admin support current and future use of nuclear power in Japan?

Anonymous said...

>Does the site admin support current and future use of nuclear power in Japan?

What does that have to do with anything? If he supports, then what?

Anonymous said...

What does reactor 3 support structure look like?

Anonymous said...

@Anon 6:46 pm

Pro-nuke power folks and anti-nuke power folks tend to have differing assessments of the situation at Fukushima don't you think?

So, what's wrong with asking a blogger what their position is?

arevamirpal::laprimavera said...

@anon at 7:12PM, I don't know if there is any support structure under the Reactor 3 SFP. I'll check if there is any info.

Anonymous said...

Anon at 6:41

Mission statements don't mean a thing. We know that.

The objectives shown on this blog, I'd say, are to to allow debate without prejudice of company procedure.

That seems to be popular here. Where is your blog? I hope there are no prejudicial ideas flowing there!

Anonymous said...

Whose mission statement are you referring to when you say: "Mission statements don't mean a thing"? Do you read a lot of established, high-traffic blogs that are in flagrant disregard of their mission statements? For example?

Also what do you mean by this phrase - "without prejudice of company procedure"?

Anonymous said...

No mission statement on huffingtonpost?

"Let's build a smarter planet is IBM's mission statement, but does that include a planet where women are considered equal to men?"
The examples in today's news of the disconnect between a corporation's mission statement and its actions teach that poor company values can lead to poor company performance -- and vice-versa.

Company prejudice From
Engineers face company prejudice From

Anonymous said...

Concrete is weak in tension and strong in compression. It is reinforced with steel, which is strong in tension and weak in compression, so the two complement each other well. Where the supporting wall was built, the top of the concrete slab forming the bottom of the pool was in compression and the bottom of it was in tension. Accordingly, most of the reinforcing steel would have been placed in the bottom half of the section. The top of the section would have required little reinforcing steel, but might have had some compression steel.

By building the wall in the middle of a span, the moment curve for the concrete slab forming the bottom of the pool was inverted. Now the top of it is in tension where the wall is and the bottom part of the section is in compression. However, most of the steel would be in the bottom of the slab (below the neutral axis). Let us hope that there is enough compression steel in the top of the section to prevent the slab from cracking, as would be expected in an earthquake now that the moment curve has been inverted. This would be a result of localized stress that might have been overlooked in the whole-building type of structural analysis that TEPCO did. If reinforcement was necessary (i.e. the building was not designed with close-packing of the SPF in mind), then perhaps it should have been done differently. Hopefully they checked this and it checked out, but normally there wouldn't be enough steel when you invert the moment curve as structural engineers attempt to place steel only where it is needed for cost reasons.

Anonymous said...

This means other than an earthquake all things are good. -Head in hands.

"Hopefully they checked this and it checked out" -Head banging on desk.

arevamirpal::laprimavera said...

@anon at 10:07PM, I don't think TEPCO was the one who checked, or NISA. It was TEPCO's general construction contractors, either Kajima or Taisei, I think. At least they know much better than TEPCO.

Yosaku said...


Good to have another engineer around here. You can see the results of the seismic evaluation of the Reactor 4 SFP on page 92 of the following report:

Anonymous said...


Thanks for that reference. I had not seen it in English before and so could not read it. I think my comment is still valid. There is no specific mention of checking for moment curve inversion, but that does not mean they did not do that. One thing, however, that is helpful is that the supporting pillars are not in the middle of the span, where the moment curve would reach its maximum value (and where the inverted curve value would also be largest). Instead the added supporting pillars are at about one third of the span. This location would reduce the inverted moment, but I would still want to double check to make sure there is enough compression steel.

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