Light at the End of the Tunnel for Japan's Nuclear Crisis?


Photo: Digitalglobe, CC
Latest Update: Japan's Nuclear Crisis: 2 Weeks After the Mega-Quake & Tsunami (March 25, 2011)

Closer to Restoring Power at Japan's Damaged Nuclear Power Plant
Another day, another update on the situation at Fukushima Daiichi in Japan. While the workers who are trying to bring the nuclear power station back under control aren't out of the woods yet, there are some encouraging signs of progress. They are getting closer to restoring electrical power in the most damaged reactor units and in the control room, which would allow for the reactors and spent fuel pools to be cooled much more easily and for the situation to be monitored more accurately. Read on for more details on what happened in the past day.
Click for bigger version. Via Wikipedia, based on official JAIF chart.

According to TEPCO, work to recover grid power for the entire plant is in progress. So far power has been restored to the distribution switchboard for unit #2. "Integrity checks of electrical equipment in Unit 2 are in progress; these must be completed before the equipment can be powered." But unfortunately steam coming out of the spent fuel storage pool at unit #2 slowed down these efforts Tuesday.

Grid power has also been partly restored to units #5 and #6 using emergency diesel generators.

If electrical power is restored to command center of the plant, it will be much easier to monitor heat and water levels at the various reactor units. Right now, the nuclear workers are often forced to speculate and use aerial photos to find out what is going on, which is definitely sub-optimal.


Photo: Digitalglobe, CC

Still according to TEPCO, "The more immediate threat is damage to fuel in the spent fuel pool (SFP), because it is outside the containment vessels. Spraying water onto the SFPs in Units 3 and 4 is continuing. Reductions in ambient radiation around the plant suggest that this spraying has been effective in cooling down the SFPs."

In a NHK report, Keigo Enda, a Gunma University professor, said "radiation released by iodine-131 had been found to be 430 times the level normally detected in soil in Japan and that released by cesium-137 was 47 times normal levels." Professor Endo added that there was "no immediate health risk but that the radiation levels would require monitoring". (Via NYT)

Always remember that when the media reports levels 100s of times the normal levels, we must remember that "normal" can be a very low baseline, so it doesn't automatically mean that it is a serious health risk. To know what those doses represent, we must go one step further and look at radiation dose charts to see if they are close to dangerous levels.

How much spent fuel is stored at the Fukushima 1 nuclear power plant? According to SciAm:

  • Reactor No. 1: 50 tons
  • Reactor No. 2: 81 tons
  • Reactor No. 3: 88 tons
  • Reactor No. 4: 135 tons
  • Reactor No. 5: 142 tons
  • Reactor No. 6: 151 tons

Uranium being very dense (it has the second highest atomic weight of the naturally occurring elements), the volume of the spent fuel is relatively small.


#27 shows the location of the spent fuel. Image: Wikipedia, CC

British writer George Monbiot published a piece that explains why the Fukushima nuclear crisis changed his mind about nuclear power, and not in the way that might be expected:

You will not be surprised to hear that the events in Japan have changed my view of nuclear power. You will be surprised to hear how they have changed it. As a result of the disaster at Fukushima, I am no longer nuclear-neutral. I now support the technology.

A crappy old plant with inadequate safety features was hit by a monster earthquake and a vast tsunami. The electricity supply failed, knocking out the cooling system. The reactors began to explode and melt down. The disaster exposed a familiar legacy of poor design and corner-cutting. Yet, as far as we know, no one has yet received a lethal dose of radiation.

Some greens have wildly exaggerated the dangers of radioactive pollution. For a clearer view, look at the graphic published by xkcd.com. It shows that the average total dose from the Three-Mile Island disaster for someone living within 10 miles of the plant was one 625th of the maximum yearly amount permitted for US radiation workers. This, in turn, is half of the lowest one-year dose clearly linked to an increased cancer risk, which, in its turn, is one 80th of an invariably fatal exposure. I'm not proposing complacency here. I am proposing perspective.

We posted the XKCD Radiation Dose Chart yesterday. You can read the rest of Monbiot's piece here.

Previous Updates on Japan's Nuclear Crisis at Fukushima
-March 14: Mini-FAQ About Japan's Nuclear Power Plant Crisis
-March 15: 6 Important Questions About the Crisis at Japanese Nuclear Power Plants
-March 16: Update on Japan's Nuclear Crisis at Fukushima I
-March 17: Ongoing Crisis at Japan's Fukushima I Nuclear Power Plant
-March 18: Japan's Nuclear Crisis, One Week Later
-March 21: Limited Progress Cooling Fukushima's Nuclear Reactors
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