Experts: Scrapping Fukushima plant could take decades

[highplainsdem]

Source: Asahi Shimbun

Experts: Scrapping Fukushima plant could take decades
2011/04/02

Regaining control of the four stricken reactors at the Fukushima No. 1 nuclear power plant could take months or years, according to nuclear experts.

And, even if the reactor cores can be cooled below 100 degrees, known as the "cold shutdown" stage, decommissioning will take several decades.

-snip-

After the Chernobyl nuclear accident in the former Soviet Union, that plant's No. 4 reactor was encased in concrete.

However, Keiji Miyazaki, professor emeritus of nuclear reactor engineering at Osaka University, warned that heat from the encased fuel could crack the concrete and release radioactive material into the atmosphere.

-snip-

Read more: http://www.asahi.com/english/TKY201104010160.html

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The Asahi Shimbun is Japan's second-largest paper: http://en.wikipedia.org/wiki/Asahi_Shimbun

This article goes into great detail on the technical challenges, explaining why what was done at TMI (removing the fuel, which would take years at Fukushima and require help from other countries) could be more relevant to this crisis than what was done at Chernobyl, when the reactor was entombed.

[freshwest]

1. Job security for the pro-nuke crowd. At least someone will be happy.

[kestrel91316]

2. Well, then, you'd best get started, folks.

[applegrove]

3. Thanks for posting this.

[highplainsdem]

4. More on the risks of entombing the reactors:

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-

[grahamhgreen]

6. "$300 billion is far too low"??? What does that make the cost per Mwh for the electricity generated?

[grahamhgreen]

5. No Way! Ann Coulter and Obama's Nuke Lobby are going to live on top of it and get free heating!

[aquart]

7. Damned expensive, that cheap nuclear energy.

[defendandprotect]

8. ... and how many more lives lost if this takes decades -- ???