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Negligent design doomed the Fukushima Daiichi Nuclear Power Plant to failure.  (Source: AP Photo)
Company is forced to examine whether quake may have damaged the plant buildings or generators, as well

Something happened at the Fukushima Daiichi that's only happened once before in the history of nuclear power -- a full meltdown occurred.  Only this time, unlike the previous incident at Chernobyl in Soviet Ukraine, a natural disaster was to blame.

I. TEPCO Gives Disaster Timeline

In the wake of the disaster Tokyo Electric Power Company (TEPCO) (9501), the operator of the damaged plant, is still working to clean up the contaminated water now that the rods have been cooled.  

And it's facing tough questions from the Japanese government, both at a provincial and national level.  The governor of Fukushima recently admonished the head of TEPCO and ordered that the Fukushima I (Daiichi) Power Plant be permanently shut down.

TEPCO has released a new report, trying to sate the Japanese government's demands.  The analysis provides a fascinating timeline of the events that are believed, based on evidence, to have occurred in the early hours of the disaster.

According to the timeline, within 5 hours of the quake, which occurred on March 11, the fuel rods were exposed and rapidly melting.  By the next morning, 16 hours later, the uranium rods in Reactor No. 1 had melted down and dropped to the bottom of the core's cylindrical steel containment vessel, which holds the nuclear fuel during reactions.

Reactors No. 2 and 3 also melted down, following a similar frame of events. 

As the Japanese pumped in water to cool the damaged reactor, it leaked out of the containment vessel, creating a large pool of radioactive water.  This water contains longer-lived isotopes like Caesium-137, which has a half-life of 30 years, approximately.

Authorities fear that the water could leak, contaminating ground and seawater.

II. Chance to Advert Meltdown May Have Been Lost Due to Inaction

On the morning after the quake TEPCO finally decided to vent steam from the reactors in an effort to reduce them from heating.  One thing the Japanese government is upset about is that TEPCO didn't vent them sooner.  It was instructed to vent them on March 11, but failed to act until the next morning.

Nuclear Safety Commission Chairman Haruki Madarame told Japan's Parliament, "We can certainly say that if the venting took place a little earlier, we could have prevented the situation from worsening."

Prime Minister Naoto Kan and Trade Minister Banri Kaieda also criticized TEPCO, stating that they had ordered the company to act, but that it did not immediately do so.  Stated Mr. Kaieda, "We had instructed them to go ahead with the vent and I think Tokyo Electric was trying to do this. Even though we asked them repeatedly to vent, it did not happen and so we decided to issue an order. All of us there, including the prime minister and myself had said it should be done as soon as possible."

It is thought if the steam was vented sooner the rods could have been cooled faster, preventing the full meltdown that occurred.

III. Did the Quake Damage the Plant?

TEPCO, under government orders, is now conducting a study examining the events immediately after the record-setting magnitude 9.0 quake that struck Japan.  The question being raised is whether the quake itself could have damaged the reactor building or backup generators.

It is widely believed that the plant escaped the quake intact, with all reactors properly terminating nuclear reactions.  It is thought that the subsequent tsunami flooding was what knocked out the backup generator, preventing the rods from being properly cooled down.

The possibility that the quake itself damaged the backup generators hasn't been ruled out, though.  Junichi Matsumoto, a spokesman for Tokyo Electric Power Co on nuclear issues, told reporters, "We want to review the data from the 40 to 50 minutes between the time of the earthquake and when the tsunami struck."

Japan's Kyodo news agency cited an unnamed source as claiming that the reactor building at Reactor No. 1 is though to have sustained structural damage from the quake.  This is troublesome as it raises the possibility that radioactive water may have leaked from the building after it seeped out of the containment vessel housed inside.

IV. Conclusions

The Fukushima nuclear disaster shows the dangers of using ancient reactor designs in flood-prone regions without proper precautions.  TEPCO likely skipped on flood proofing the backup generators for expense reasons, but in the end paid a far greater cost for their negligence.

The disgraced firm has been working hard to try to minimize the damage resulting from accident.  In that regard, it is perhaps handling the incident better than authorities did Chernobyl.

However, the familiar themes of outdated technology and gross negligence were central to both the Chernobyl and Fukushima stories.

The impact of the disaster remains to be seen, but one thing is for the sure -- the accident stands as a stirring cry to decommission older reactors and move to modern designs, and as damning condemnation on engineering negligence.



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RE: Speculation, as always by Mick.
By Tuor on 5/19/2011 2:38:53 PM , Rating: 2
quote:
Sure it's not easy to build new reactors, but consider that new reactor designs literally can't melt down (they're passively cooled). Is there really any justification for not starting this transition in as timely a manner as possible?


There are two: time and cost. There is considerable time involved in planning, getting the permissions and permits approved, doing the various studies required, and then the actual construction. Because of this, the gap between reactor designs and reactors built and producing power is always going to be considerable.

As for cost, it is my understanding that land is pretty expensive in Japan, and land that is properly situated for building a nuclear reactor even more so. If you're talking about swapping out reactors, then that means you'll have to take the old reactor off line and it will no longer be generating revenue. I brought up the Space Shuttle previously: NASA was obliged to use it as long as it felt it could safely do so, despite the fact that spacecraft design and material science has advanced a great deal since when they were designed. TEPCO is in the same position: you don't stop with the current setup until you've wrung everything you can out of it and it can no longer produce power within safe operating margins.

Ideally, yes, they would say, "Well, this reactor is getting long in the tooth and we'll have to replace it soon, better start moving on its replacement." But TEPCO has to go through lots of hoops to do that, as I mentioned previously.

As far as new reactors being capable of greater output. That's all well and good, but how long until the difference in output covers the cost of building a new reactor? If your point is that TEPCO will make more money by switching to a new reactor design, then *when* they see any profit from the replacement becomes relevant.

quote:
I'm sorry but your goal as an engineer should be to make a design that works, not a design that narrowly meets government regulations.


Qualify "design that works". Do you mean a design that allows the most efficient production of power possible? One with the greatest lifetime? One that is the most stable? It all depends on the goals in mind. Safety and stabilty are certainly major goals. Engineers look at *all* of the design criteria and prioritize them. The government is aware that companies like TEPCO cannot operate at a loss and so they put in regulations that ensure that companies don't lose sight of public safety concerns in their money-making goals. This is one of the main reasons government oversight exists. It is TEPCO's responsibility to operate according to regulations and it is the government's responsibility to make sure those regulations are effective.

If TEPCO was following regulations, then how can they be legally responsible? If they were *not* following regulations, then punishment will be forthcoming.

You liken this tsumani to floods in Luisiana, despite the fact that this is one of, if not the largest tsunami ever recorded in Japan. How much of a safety factor should they have used? They used enough for any forseeable situation, and the government approved it. If they'd gone short of that, then I could see reason to be upset (as well as numerous lawsuits), but so far as I am aware, they didn't do that.

I would love to see lots of modern designed reactors producing power, both in Japan and here where I live in the USA. I agree that bad press and ignorance is responsible for a lot of hand-wringing and confusion about nuclear power production. However, browbeating TEPCO over not having been prepared for a 9.0 earthquake producing a tsunami that created a wave of around 70 feet in height is, IMO, unfair.


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