Marvin Resnikoff: Fukushima 2.0 ("TEPCO is moving the disaster into uncharted waters")

[highplainsdem]

I posted this first as a reply adding information to a thread in LBN

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=102x4797577

but I wanted to post it as a separate thread in GD so more people would read it.

______


This HuffPo article was written by an expert on radioactive waste management, and he seems to be assuming that TEPCO has definitely decided to entomb the reactors. (I've known they were considering it, wasn't sure that was definite yet.)

http://www.huffingtonpost.com/marvin-resnikoff/fukushima-20_b_843558.html

Marvin Resnikoff
Senior Associate, Radioactive Waste Management Associates
Fukushima 2.0
Posted: 04/ 1/11 02:35 PM ET


Doomsday Scenario 2.0

With the decision to entomb four Fukushima reactors in concrete, Tokyo Electric (TEPCO) is moving the disaster into uncharted waters. The heat producing fuel rods cannot be turned off. Concrete will insulate the heat from the fuel rods, and cause the internal temperatures to climb. The nuclear fuel will melt down and pass through the bottom of the reactor vessel and containment structure and enter the environment. The radionuclides, primarily cesium-137 and strontium-90, but also plutonium and others, will enter the sea. The human health and economic costs will be enormous.

TEPCO's choices were limited. The brave workers who were attempting to put a lid on atmospheric releases were fighting a valiant, but losing battle. Iodine was entering the air and the sea. Iodine concentrations in the sea were already over 4,300 times safe limits and in the plant, greater than 10,000 times safe limits for nuclear workers. Cesium, a semi-volatile metal, was also entering the sea through unknown pathways, likely leakage from below. Clearly the cladding around the nuclear fuel rods and the reactor vessel had been breached. So the choice was to continue to expose workers to extremely high radiation doses, while releasing cesium and iodine to the air and sea, or close it down, cover it with concrete and let the reactor cores and fuel pools melt into the ground and into the sea.

Fukushima Inventory

Assuming four reactors are coated with cement, and reactors 5 and 6 and the common ground level shared fuel pool can be saved, we can give a rough estimate of the radioactive inventory and compare it to two other nuclear disasters: Hiroshima and Chernobyl. Roughly, 2,100 Curies of cesium-137 were released at Hiroshima. At Chernobyl, according to the UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation, 2000), 2.3 million Curies of cesium-137 were released. The approximate inventory of reactors 1 through 4 is 100 million Curies cesium-137, or more than 40 times the Chernobyl release, and 48000 times the Hiroshima release of cesium-137. (spreadsheet available). Only a fraction of this Fukushima inventory has been released to-date. If a sizable release takes place, say 10% of the Fukushima inventory, this represents 8 times the Chernobyl release and 4,800 times the Hiroshima release. This would be a major catastrophe. Cesium would not just dissipate in the ocean or concentrate in fish; it will also wash back to shore. This will make it difficult for workers to service reactors 5 and 6.

The Implications

The implications of cementing over reactors 1-4 are not clear. With the cesium-137 and iodine-131 releases from Fukushima, the evacuation zone is out to 30 miles, but a much larger coastal zone may ultimately be affected for many decades. The internal heat may explode the containment and cause additional cement cracking. The heat will certainly melt through the bottom of the reactor vessel and containment and into the underlying soil. The human health and cost implications of this accident could be enormous. Four hundred thousand Japanese have already been displaced by the tsunami and the forced evacuation. The present cost estimate of $300 billion, before the decision to cement over the four reactors, does not account for the long-term loss of the coast. Based on our cost estimates for potential nuclear transportation accident for the State of Nevada, we believe $300 billion is far too low. TEPCO may go into receivership and be taken over by the government. The Japanese economy, struggling before this accident, will take another hit.

-snip-

[Zoeisright]

1. Good. God.

We really have unleashed the monster.

[highplainsdem]

2. IEEE: Nuclear Risk Expert: Fukushima's Fuel Could Still Seep Out

http://spectrum.ieee.org/tech-talk/energy/nuclear/nuclear-risk-expert-fukushimas-fuel-could-still-seep-out

-snip-

It's Theo Theofanous's job to worry about worst-case scenarios. As director of the Center for Risk Studies and Safety at UC Santa Barbara, he tries to quantify the unthinkable and calculate the likelihood of utter disaster. He has studied everything from chemical weapons to natural gas pipelines--but for a 15-year stretch in the 1980s and 1990s, he focused on nuclear reactors.

-snip-

His findings on reactors' vulnerabilities have given him insight into the emergency that continues to grip Japan. Four of the six reactors at the damaged Fukushima Dai-1 nuclear plant are boiling water reactors that use a "Mark 1" containment system designed by General Electric in the 1960s. Theofanous studied what would happen in a Mark 1 reactor if the cooling systems failed and the nuclear fuel overheated and melted, as some experts think may have happened in at least one of Fukushima Dai-1's reactors.

-snip-

If melted fuel escapes the reactor vessel and collects on the floor of the drywell it stills need to be continuously cooled, since it still produces decay heat even after the nuclear fission reaction has stopped. And that cooling procedure can be difficult. "Even if you flood the place with water, there's no guarantee that you can keep it cool," says Theofanous. "The fuel can form a crust, isolate itself from the water, and keep on eating through the concrete floor." The fuel could then eat all the way through the floor and drip into an area called the pedestal room--a chamber below the drywell that's surrounded by the doughnut-shaped wetwell. From there, the radioactive material could more easily reach the environment.

Has this scenario been playing out at Fukushima Dai-1 in the three weeks since the earthquake and tsunami damaged the nuclear plant? Theofanous says that from the current reports, it's impossible to say for sure. "We don't really know where the fuel is," he says. "My guess is that for the bigger 740 megawatt reactors that were badly damaged, reactors 2 and 3, the fuel is out into the drywell. If it is there, it keeps on eating through the concrete."

-snip-

Emphasis added.

The most reassuring news in the rest of the article is that it's a lot of concrete, since it should be 5-10 meters (I hope that's right and this isn't one of those situations where it's discovered later that they cut corners when building the reactor).

But it will eventually melt through.

Theofanous says the radioactive water that's accumulating is the more immediate problem. The final quote from him in that paragraph is, "I still don't know how they're going to get out of this."

According to the article, he tried to get the NRC to do more studies on failures like this happening after an initial accident, but "they didn't want to deal with it" and he "got disgusted and left the nuclear business."

[aquart]

3. We really have to stop playing with "could" and "maybe" now.

There is NOTHING to stop the fuel from eating through the cement to....WHAT? What will it reach and THEN what WILL happen because there is nothing we can do to stop it because we have never bothered to think it through.

How far will the contamination go?

What will it do to the ocean? Fish are not stationary. Is that a food source destroyed? Partially? Entirely?

What will it do to the islands of Japan? Where will the people go who can never go home again?

What will it do to the rest of us, far far away...living next to identical reactors?

What will it do to the children about to be born?

What will it do to the children already here?

[Electric Monk]

4. They used to call it China Syndrome

http://en.wikipedia.org/wiki/China_Syndrome

as in, the meltdown would burn all the way through to the other side of the planet.


It wouldn't, of course. Once it reached the core, gravity would be equal in all directions.

What happens after that, I don't know.

Sol becomes a binary star system?

The pile just gets absorbed in the planetary core and nothing else happens?

Something in between?

I don't know.

[localroger]

11. Actually, it only gets as far as the ground water

Ground water turning to steam (initially in a big fat explosion) disperses the material into the environment.

[intaglio]

10. Trouble is "could" and "maybe" is all anyone has

You start with an engineering problem that has too many unknowns. For example how does "corium" (in itself a largely undefined witches brew) affect concrete? How does that vary with temperature? How does water affect the problem?

You move into physical unknowns. How does the fissile material (stuff that decays on its own) and the fissionable material (stuff that decays when hit by neutrons and other particles from the fissile mats.) interact in the highly variable environment of corium/concrete/water. How often is temporary, self criticality likely to happen and how does that feed back.

Then the geophysical problems. How do radionuclides interact with soil and groundwater? How does heat affect this? How mobile are the various radionulides in this situation?

Biological problems, oceanic and atmospheric transportation problems.

[grahamhgreen]

5. "we believe $300 billion is far too low", nuclear power is too expensive, dirty and dangerous es-

pecially when you factor in even one accident

[Urban Prairie]

6. Hmm..the power of super hot and pressurized steam is pretty strong

So we may have perhaps the potential makings of four "capped" radioactive volcanoes, eventually exploding from the build-up of tremendous pressure from super-hot radioactive steam created from the hundreds of tons of super-hot masses of radioactive slag melting down into the water table below, and erupting with hundreds of tons of radioactive "lava" comprised of what "was" fuel pellets, and molten cement and silicon?

Yikes!!

:scared: :banghead:

[Snoutport]

7. next the pro nukers will say it is all ok. there is more radiation in a banana than a silly reactor

[Warren DeMontague]

8. Everything is dangerous! Rocks! You can get hit on the head with a rock, and die!

Next, you silly anti-nuke bedwetters will want to ban rocks!

:sarcasm:

[Snoutport]

9. I have a lovely rock collection, thank you very much.

And they have never harmed me nor wished me ill will.

[Warren DeMontague]

12. Don't kid yourself.They're plotting your overthrow as we speak.

Sure, they're doing it very slowly.


But they're up to something.

[Quantess]

13. Oops.

[Junkdrawer]

14. K&R