Meltdown?

UPDATE 3/21/2011 9:55 am PST

Grey smoke from No.3 reactor subsided

The grey smoke seen coming from the troubled No.3 reactor of the Fukushima Daiichi nuclear power plant on Monday afternoon has subsided. The plant’s operator, Tokyo Electric Power Company, evacuated its workers from the plant shortly after 4 PM. The government’s nuclear safety agency said the smoke, which turned black and grey, subsided about 2 hours later. It also said water levels and pressure inside the reactor have registered no major changes. The smoke was apparently coming from the south edge of the reactor structure. The storage pool for spent nuclear fuel is located in the southeast part of the structure. Radiation levels at a spot about 500 meters northwest of the reactor were 2,015 microsieverts per hour, almost unchanged from the figure measured before the smoke was seen. Work was under way to restore external power to the No.4 reactor and regain its cooling functions. The nuclear safety agency said the work is unlikely to have caused a fire. Government’s nuclear safety agency says it was informed that white smoke was apparently coming from a crack in the roof of the No.2 reactor structure at 6:20 PM. Similar white smoke had been seen rising from the reactor previously. On Sunday afternoon, work to inject 40 tons of seawater into the reactor’s storage pool for spent nuclear fuel was carried out, taking about 2 hours.

Monday, March 21, 2011 21:08 +0900 (JST)

External power was extended to the electricity distribution panels of the No.2 and No.5 reactors on Sunday, and power can now be supplied to reactors number 1, 2, 5, and 6. In order to get the electricity back on at the No.2 reactor, the power company plans to check various measurement devices and lighting systems in the central control room — the heart of the plant — and check for electricity leakage in the battery charging room. The No.3 and No.4 reactors, where high levels of radiation are forcing workers to exercise extreme caution, are scheduled to be connected to the electricity distribution panels on Tuesday.

Monday, March 21, 2011 17:46 +0900 (JST)

Dead or missing from quake and tsunami tops 21,000

Of 8,805 confirmed deaths, 4,080 bodies have been identified. 12,654 people have been reported missing as of 9 PM, Monday.

An economist interviewed by NHK said that they expect only a 0.05% to 1% hit to GDP. The World Bank had a much worse projection. Another expert said the cost of recovery would be less than the Kobe earthquake whereas the World Bank said it would be two times the Kobe disaster.

UPDATE 3/18/2011 2:40 pm PST

6,900 Confirmed Dead

Japanese police say they have so far confirmed 6,911 deaths in the earthquake and tsunami that hit northern Japan last week. The figure surpasses the death toll for the 1995 Great Hanshin [Kobe] Earthquake. Police say 10,316 remain missing. They suspect that many other people have not been reported as missing because entire families were lost in the disaster. The quake is Japan’s worst natural disaster in the post-war period, after the 1995 Great Hanshin Earthquake, which claimed 6,434 lives.

Friday, March 18, 2011 15:42 +0900 (JST)

Nuke plant disaster rating raised to Level 5

The Japanese government raised its rating on Friday of the problems at the Fukushima Daiichi nuclear plant to the same level as the 1979 Three Mile Island accident. The Nuclear and Industrial Safety Agency revised upward its evaluation of the severity of the disaster by one notch to Level 5 on the International Nuclear and Radiological Event Scale. Level 5 is the third highest on the 8-notch scale and the worst for any nuclear accident to have happened in Japan. The agency says it raised the rating because more than 3 percent of the nuclear fuel has been damaged and radioactive material is leaking from the plant. The disaster’s initial rating of Level 4 was the same as the fatal criticality accident that occurred at a nuclear fuel plant in Ibaraki Prefecture in 1999.

Friday, March 18, 2011 20:01 +0900 (JST)

High radiation detected 30km from nuke plant

Japan’s science ministry says relatively high radiation levels have been detected on 2 consecutive days about 30 kilometers northwest of the quake-damaged Fukushima Daiichi nuclear power plant. The radiation measured 170 microsieverts per hour on Thursday and 150 microsieverts on Friday. Chief Cabinet Secretary Yukio Edano says the government will take appropriate measures if this level of contamination continues in the area for a long period. But he says this would be unlikely. Radiation was measured for 2 hours from 10AM on Friday at 18 spots in areas 30 to 60 kilometers from the plant in Fukushima Prefecture. The highest reading of 150 microsieverts per hour was detected at around 1:30 PM local time, about 30 kilometers northwest of the plant. The location is within the zone where residents have been instructed to stay indoors. Readings of 170 microsieverts were recorded at the same location at 2 PM on the previous day, Thursday. Experts say exposure to this amount of radiation for 6 to 7 hours would result in absorption of the maximum level considered safe for one year. The ministry also observed radiation levels of 0.5 to 52 microsieverts per hour at other observation points within a 30 to 60 kilometer radius of the plant. It says these levels are all higher than normal, but not an immediate threat to health. The government has evacuated residents living within a 20 kilometer radius of the plant, and instructed those in a 20 to 30 kilometer radius to stay indoors.

Friday, March 18, 2011 17:38 +0900 (JST)

Dosage — from Wikipedia

Single dose examples

Hourly dose examples

  • Approximate radiation levels near Chernobyl reactor 4 and its fragments, shortly after explosion are reported to be 10–300 Sv/hr

Yearly dose examples

  • Living near a nuclear power station: 0.0001–0.01 mSv/year[5][1]
  • Living near a coal power station: 0.0003 mSv/year[1]
  • Cosmic radiation (from sky) at sea level: 0.24 mSv/year[5]
  • Terrestrial radiation (from ground): 0.28 mSv/year[5]
  • Natural radiation in the human body: 0.40 mSv/year[5]
  • Radiation produced by the granite of the United States Capitol building: 0.85 mSv/year[7]
  • Average individual background radiation dose: 2 mSv/year; 1.5 mSv/year for Australians, 3.0 mSv/year for Americans[1][8][3]
  • New York-Tokyo flights for airline crew: 9 mSv/year[8]
  • Atmospheric sources (mostly radon): 2 mSv/year[9][5]
  • Total average radiation dose for Americans: 6.2 mSv/year[10]
  • Smoking 1.5 packs/day: 13-60 mSv/year[7][11]
  • Current average limit for nuclear workers: 20 mSv/year[8]
  • Background radiation in parts of Iran, India and Europe: 50 mSv/year[8]
  • Lowest clearly carcinogenic level: 100 mSv/year[8]
  • Elevated limit for workers during Fukushima emergency: 250 mSv/year[12]

 

UPDATE (3/15/11  10:46 pm PST)

Getting reliable current information about the Fukushima power plant is becoming difficult. This story was on NHK but whether this water level issue is still a problem is unclear. I don’t think anyone except those on the ground have a clear idea of what is happening, much less what will happen.

Agency: Water level falls in No.5 reactor

The Nuclear and Industrial Safety Agency says the coolant level has fallen in the No.5 reactor at the Fukushima Daiichi nuclear power plant. The Agency had earlier said the No.5 reactor stopped safely during a regular inspection when the massive earthquake and tsunami occurred on Friday. At the time of the quake, nuclear fuel rods were already in the reactor and workers had to circulate water to cool them down. But the tsunami damaged a diesel generator for circulating the coolant, allowing the pressure in the reactor to rise. Workers opened a valve to reduce the pressure. But the procedure allowed water to evaporate from the valve.

As of 9 PM on Tuesday, the water level was 2 meters above the fuel rods. That was 40 centimeters lower than 5 hours earlier. The Agency says it can adjust the water levels by using the No.6 reactor’s generator, which wasn’t damaged by the tsunami. Workers are currently pumping water into the No.5 and No.6 reactors.

Wednesday, March 16, 2011 07:34 +0900 (JST)

There are reports coming out now that the remaining workers have been pulled off the site because radiation levels are high. Reuters says they were only pulled off for a short period. The same government official, Chief Cabinet Secretary Yukio Edano, said that the No. 3 reactor containment vessel has been “compromised.”

We still don’t know what’s going to happen.

* * * * *

Original Article

Meltdown? Couldn’t happen (they say). I don’t mean to sound alarmist, but no one knows what is going to happen to the Fukushima nuclear power plant. When you deal with these kinds of Black Swan events, you weigh the probabilities, not the possibilities. It is highly probable that things could go very wrong with Tokyo Electric Power’s attempt to control their reactors.

While it seems unlikely that a core meltdown would occur, I would take the soothing words of experts put on TV by the Japanese news media with a grain of salt. Professor Takeda, an expert in nuclear safety systems, said on NHK that things are “different” here. “They must cool down the reactors,” he said. “The situation will end eventually if they do everything they are trying.” I don’t think anyone at this time could state with any certainty that a meltdown won’t occur.

It is human nature to see things in a positive light, not believing that it could happen here. We are instant experts in the subject. As Nassim Taleb puts it in The Black Swan, when discussing the various empirical tricks we experience when evaluating risks (page 50):

  • We focus on preselected segments of the seen and generalize from it to the unseen: the error of confirmation.
  • We fool ourselves with stories that cater to our Platonic thirst for distinct patterns: the narrative fallacy.
  • We behave as if the Black Swan does not exist: human nature is not programmed for Black Swans.
  • What we see is not necessarily all that is there. History hides Black Swans from us and gives us a mistaken idea about the odds of these events: this is the distortion of silent evidence.
  • We “tunnel”: that is, we focus on a few well-defined sources of uncertainty, on too specific a list of  Black Swans (at the expense of the others that do not easily come to mind.)

The bottom line is that we don’t know what is going to happen. The government doesn’t know what’s going to happen. And the Tokyo Electric Power Company which is trying to control the reaction doesn’t know what is going to happen. It would be foolish to not take precautions. My advice, without trying to sound panicky, is to get the hell out of Dodge.

 

The executives of the Tokyo Electric Power Company today explaining the problems do not give me a lot of confidence:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For those of us on the West Coast, pay attention.

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2 comments to Meltdown?

  • John Anderson

    MIT’s Department of Nuclear Science & Engineering has an article full of facts that’s very straightforward.

    http://mitnse.com/2011/03/13/why-i-am-not-worried-about-japans-nuclear-reactors/

    They may not be fortune tellers, but I tend to think MIT can be trusted with sort of thing.

  • Jim

    It’s quite sobering to think that a city of 35,000,000 people may have to deal with radioactive fallout. And the city is on an island.
    Today we have conflicting reports from US officials and the Japanese Govt. The Helicopters dumping water on the reactors seems to be a last ditch effort to cool the reactors. I can see why the citizens there are skeptical of the government and TEPCO information.