Saturday, August 27, 2011

Fukushima's Spent Fuel Pools

Today Fukushima's spent fuel pools are a major topic of discussion.

Arnie Gunderson just released a new report that addresses the condition of the spent fuel pools. Arnie's overall claim is that the fuel in spent fuel pools 1, 2, and 3 is damaged. Arnie examines the evidence for this claim and also addresses Tepco and NRC equivocation about the state of the fuel in the pools.

Here is the evidence used by Arnie to establish that the fuel in pools 1, 2, and 3 is damaged. He is not clear about the status of the fuel in pool #4.
http://fairewinds.com/content/newly-released-tepco-data-proves-fairewinds-assertions-significant-fuel-pool-failures-fukush

ARNIE WRITES: "Just 2 days ago, TEPCO released a report that has a water analysis of the condition of the spent fuel pools at Fukushima. This data was taken in August, August 19th and 20th, so it is very current and I wanted to share it with you today. The table is a water analysis and it says “analysis of spent fuel pool water.”

Let's go to Unit 2 and then cross over to Cesium 137. If you look at that column, it says 1.1 E8. Now what does that mean? That is 1.1 with 8 zeros behind it, or 110 million disintegrations per second in every liter of water. If you look at the next column over, that is Cesium 134. It is also 1.1 E8.

So the combination of both Cesiums in the fuel pool on Unit 2, is 220 million disintegrations per second in a liter of water.

So think of a liter Coke bottle and inside it the water is disintegrating at 220 million disintegrations every second, and that is just for Unit 2. The table also shows similar very high concentrations of Cesium in Unit 1 and in Unit 3.

It clearly shows that there is damage to the fuel in those 3 units.

The interesting thing about the table is that it shows much lower concentrations of Cesium in Unit 4. Now, it still could be that there is damage, but less damage in Unit 4. Or it could mean that contamination from the other 3 units fell into the water in Unit 4 and contaminated that water. So Unit 4 is a bit of a mystery, but Units 1, 2, & 3 clearly have significant spent fuel damage."

MAJIA HERE: The reason the spent fuel pools is such a big issue is because damaged fuel emits radiation. It seems clear to me that the fuel in the spent fuel pools is damaged. Furthermore, there is evidence that the pools themselves are damaged as well.

First, let us examine why the fissioning fuel is such a problem before taking a more focused look at additional information about the status of the pool. I start with Dr. Helen Caldicott's warning and move to news reports about spent fuel pool #2 before concluding with a discussion I've written about spent fuel pool #4.

In April (20th) Dr. Helen Caldicott Warned about the Scope and Severity of Fukushima, emphasizing the dangers of the spent fuel pools http://www.youtube.com/watch?v=4ITrXVJMKeQ&feature=share

This is a summary of what she said:
There have been 3 hydrogen explosions

2 cooling pools are dry and burning because the casing for pellets burns when exposed to air

Each cooling pool has 10 to 20 times as much radiation as in the reactor

In each reactor core is 1000 times as much long lived radiation as produced by the Hiroshima bomb

1 millionth of gram of Plutonium will give you cancer if inhaled

There are 250 kilograms of Plutonium in each reactor (only 2.5 kilograms needed to make a bomb) and plutonium is escaping into the atmosphere

MAJIA HERE: FURTHERMORE, THERE WERE REPORTS THAT SPENT FUEL POOL #2 WAS IN SERIOUS TROUBLE IN APRIL

April 19 Update No. 2 Reactor Spent Fuel Rods May Be Damaged
Tokyo, April 18 (Jiji Press)--Tokyo Electric Power Co. said Monday that spent nuclear fuel rods at the No. 2 reactor at its crippled nuclear power plant may be damaged although damage levels have yet to be known. The company said its examination of water in a tank connected to the spent fuel pool of the reactor at the Fukushima No. 1 plant, ravaged by the March 11 quake and tsunami, found 4,100 becquerels of radioactive iodine per cubic centimeter and 4,000 to 160,000 becquerels of radioactive cesium.The radioactive cesium levels are extremely high, company official Junichi Matsumoto said. The company believes the levels, compared with data on leaks from the reactor vessel, indicate that spent fuel rods have been exposed and damaged. The spent fuel pool contains 615 fuel assemblies.However, the industry ministry's Nuclear and Industrial Safety Agency believes the detected radioactive materials are likely to have leaked from the reactor vessel. http://jen.jiji.com/jc/eng?g=eco&k=2011041900007

No. 2 Reactor Spent Fuel Rods May Be Damaged: Tokyo, April 18 (Jiji Press)--Tokyo Electric Power Co. <9501> said Monday that spent nuclear fuel rods at the No. 2 reactor at its crippled nuclear power plant may be damaged although damage levels have yet to be known.  The company said its examination of water in a tank connected to the spent fuel pool of the reactor at the Fukushima No. 1 plant, ravaged by the March 11 quake and tsunami, found 4,100 becquerels of radioactive iodine per cubic centimeter and 4,000 to 160,000 becquerels of radioactive cesium.  The radioactive cesium levels are extremely high, company official Junichi Matsumoto said. The company believes the levels, compared with data on leaks from the reactor vessel, indicate that spent fuel rods have been exposed and damaged. The spent fuel pool contains 615 fuel assemblies.However, the industry ministry's Nuclear and Industrial Safety Agency believes the detected radioactive materials are likely to have leaked from the reactor vessel. http://jen.jiji.com/jc/eng?g=eco&k=2011041900007
Now I'm going to paste what I've written about the spent fuel pools, focusing on pools #4 and 3:

MAJIA WRITES: Spent fuel pools have been long acknowledged to pose significant dangers in nuclear emergencies because they contain literally tons and tons of fuel rods that remain highly radioactive and give off heat and therefore must be cooled constantly or the pools will evaporate and the rods burn, producing very high levels of radioactive contamination.

These dangers had been documented in a 2005 report by the National Academy of Sciences (Goldenberg, 2011; Murphy, 2011). The radioactive contamination from fuel pools is a particularly threatening because pools lack containment. Given these known dangers,  concerns were expressed early in the crisis that a fire in the spent fuel pools would release even more radiation than melted fuel in the actual reactors (Goldenberg, 2011 Mar 16).

On the morning of Tue March 15, the International Atomic Energy Agency (IAEA) released a statement warning that the Japanese authorities had reported a fire in spent fuel pool #4.

Japanese authorities also today informed the IAEA at 03:50 UTC that the spent fuel storage pond at the Unit 4 reactor of the Fukushima Daiichi nuclear power plant was on fire and radioactivity was being released directly into the atmosphere.

At the time of these reports, dose rates of up to 400 millisievert per hour were reported at the site. Japanese authorities stated that the the fire in the pool was caused by a hydrogen explosion. (http://www.iaea.org/press/?p=1248)

The fuel pool fire was reportedly extinguished later on March 15 (IAEA http://www.iaea.org/press/p=1252).

However, Jim Riccio, a nuclear expert for Greenpeace, reported on March 16 to The Guardian that the spent fuel pool at unit 4 was still boiling: "The spent fuel pool in unit 4 is boiling, and once that starts you can't stop it… The threat is that if you boil off the water, the metal cladding on the fuel rods that is exposed to the air, and is volatile, will catch fire. That will propel the radiation even further" (cited in Goldenberg, 2011 3/16).

On March 19, The Los Angeles Times reported that spent fuel pool #4, which contained the reactor core for unit 4, was cracked and leaking, and in danger of overheating (Maugh, 2011). The report that a fire occurred at spent fuel pool #4 was later confirmed in an IAEA report (IAEA “Japanese Earthquake,” 2011), although the U.S. Nuclear Regulatory Committee subsequently tried to deny it in June (Daly, 2011).

On June 20th Tepco reported that the water in spent fuel pool #4 was down by two-thirds as of June 11th and that radiation levels were so high workers could not approach the pool (“Tepco Injects http://www3.nhk.or.jp/daily/english/20_03.html).

The pool at Unit #4 was not the only one to have problems. The Guardian reported on March 16 that a fire had broken out in the #3 spent fuel pool (Goldenberg http://www.guardian.co.uk/environment/2011/mar/16/japan-nuclear-fire-fuel-pools-radiation?INTCMP=ILCNETTXT3487).

Nuclear engineer Arnie Gunderson of Fairewinds subsequently reported in one of his video-updates of the disaster that he believed the explosion at the number 3 reactor in March was caused by “prompt criticality” in number 3’s fuel pool, rather than in the reactor itself (Gunderson, http://fairewinds.com/content/gundersen-postulates-unit-3-explosion-may-have-been-prompt-criticality-fuel-pool?).

A media blackout on the exact condition and status of unit #4’s and unit#3’s spent fuel pools subsequent ensued for the next few months although large amounts of steam could be seen released from the general vicinities of the spent fuel pools for units 3 and 4 on Tepco’s live video cam trained on the Fukushima plants (http://www.tepco.co.jp/nu/f1-np/camera/index-j.html).


3 comments:

  1. Hi !

    Long time I have asked myself the issues of reconstruction: in how long can it be built a nuclear power plant operational? The proximity of such buildings could facilitate the transfer of the bars which, in this new plant, would not pose an problems. (?)
    Since 6 months why have they not built a roof on reactors? Even if 4 roofs were prefabricated, they could then be consolidated by pouring of concrete. Idem for the walls.

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  2. Great summary!
    One question about your comments above:
    "There are 250 kilograms of Plutonium in each reactor (only 2.5 kilograms needed to make a bomb) and plutonium is escaping into the atmosphere"
    ... I thought only one reactor (#4) had MOX fuel rods with Plutonium!

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  3. My understanding is that plutonium is a by-product of the uranium fuel fission process.

    I am not an expert and am simply recalling what I've read others state, but I think the data support this interpretation.

    check out this post by blogger Ex-SKF
    http://ex-skf.blogspot.com/2011/08/radionuclides-released-into-air-from.html

    In this post, Ex-SKF examines Japan's nuclear agency report on radionuclides released from the report. He links the pdf report.

    here is a summary of Ex-SKF's reading of the report:

    "More plutonium came out from Reactor 2, 2-digit higher, not from Reactor 3 with MOX-fuel.

    Strontium-89 (in becquerels)
    Reactor 1: 8.2 x 10^13 (or 82 terabecquerels)
    Reactor 2: 6.8 x 10^14 (or 680 terabecquerels)
    Reactor 3: 1.2 x 10 ^15 (or 1,200 terabequerels)
    Total: 2.0 x 10^15 (or 2,000 terabequerels)

    Strontium-90 (in becquerels)
    Reractor 1: 6.1 x 10^12 (or 6.1 terabecquerels)
    Reactor 2: 4.8 x 10^13 (or 48 terabecquerels)
    Reactor 3: 8.5 x 10^13 (or 85 terabecquerels)
    Total: 1.4 x 10^14 (or 140 terabecquerels)

    Plutonium-241 (in becquerels)
    Reactor 1: 3.5 x 10^10 (or 35 billion becquerels)
    Reactor 2: 1.2 x 10^12 (or 1.2 terabequerel)
    Reactor 3: 1.6 x 10^10 (or 16 billion becquerels)
    Total: 1.2 x 10^12 (or 1.2 terabequerel)

    Neptunium-239, which decays to plutonium-239, was estimated at 7.6 x 10^13 becquerels, or 76 terabequerels, adding to 3.2 x 10^9 becquerels of plutonium-239 that came out. Again, most neptunium-239 came out of Reactor 2, whose reactor building is more or less intact and whose Suppression Chamber is said to have been damaged on March 15 morning.

    In the PDF file linked above, NISA estimated 770,000 to 850,000 terabecquerels of radioactive materials have been released into the atmosphere from Fukushima I Nuke Plant (although they are now trying to lower that number), and additional 720,000 terabecquerels of radioactive materials are in the contaminated water at the plant..."

    read the entire post at the link above

    Unless I am mistaken, I think we see in this report that plutonium is a byproduct of the fissioning of fuel that is not mox fuel

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