Forensic Analysis Of Events At Fukushima Nuclear Plant

Zero Hedge and World Nuclear News ^ | 03/12/2011 | World Nuclear News

[Nobel_1]

Three of Fukushima Daiichi's six reactors were in operation when yesterday's quake hit, at which point they shut down automatically and commenced removal of residual heat with the help of emergency diesel generators. These suddenly stopped about an hour later, and this has been put down to tsunami flooding by the International Atomic Energy Agency (IAEA).

The loss of the diesels led the plant owners Tokyo Electric Power Company (Tepco) to immediately notify the government of a technical emergency situation, which allows officials to take additional precautionary measures.

For many hours the primary focus of work at the site was to connect enough portable power modules to fully replace the diesels and enable the full operation of cooling systems.

[Nobel_1]

Additional analysis on Zero Hedge now ... why this does not look like Chernobyl:

http://www.zerohedge.com/article/fukushima-explosion-update-core-presumed-intact-sea-water-used-bring-temperature-down-radiat

“The explosion at No. 1 generating set of the Fukushima nuclear plant in Japan, which took place today, will not be a repetition of the Chernobyl nuclear disaster,” said Valeriy Hlyhalo, deputy director of the Chernobyl nuclear safety centre.

He was quoted by Interfax news agency as saying Japanese reactors were better protected than Chernobyl, where just over 30 firefighters were killed in the explosion. The world’s worst civilian nuclear disaster, Chernobyl has also been blamed for thousands of deaths due to radiation-linked illness.

“Apart from that, these reactors are designed to work at a high seismicity zone, although what has happened is beyond the impact the plants were designed to withstand,” Hlyhalo said.

“Therefore, the consequences should not be as serious as after the Chernobyl nuclear disaster.”

[EBH]

And I bet you didn’t have plans for a historic level earthquake and a tsunami at the same time.

[NonValueAdded]

Could the source of the cesium and iodine be from a compromised fuel pool and not the main reactor? The pool is up high in that cutaway.

[SueRae]

Thanks for answering, much appreciated.

[meatloaf]

I wouldn’t be concerned about it.

[meatloaf]

“Driving home Friday evening, I heard an ABC Radio News’ ‘nuclear expert’ state that the reactor ‘might explode’.” I’d be more concerned about his head exploding. The reactor won’t.

[Riley]

My point exactly. Well, apart from a well-deserved mocking of ABC Radio News.

[Bean Counter]

I had read that this was an older design but I didn’t realize they were that close to the end of useful life. Perhaps this will prove to be an opportunity to get a modern design built to replace this unit, if they can salvage it.

I also heard they were preparing to pump boric acid into one of the units to damp the nuclear reaction, and that implies near fatal damage to that unit. It will probably prove to be difficult to decommission but I do not think it will pose the risk of a major release, on the scale of a Chernobyl event.

I keep coming back to Chernobyl as the ultimate worst possible case accident for a nuclear reactor. The design of even these older model Japanese reactors are light-years beyond Chernobyl in safety and the chances of an extreme accident that exposes a burning core are extremely remote.

[Mears]

God,I feel so stupid when I read this stuff.

I think I’ll just go back to praying and crossing my fingers.

[backwoods-engineer]

Thanks for a great thread, and sound, factual information on the Japanese reactors. You three FReepers are better than any nuclear "expert" the lamestream media has had on. I would to God that the public at large could read and understand this thread.

We need nuclear power now more than ever, and the fear-mongering that the lamestream media is doing just hurts any effort to expand construction of such plants in this country.

[Nobel_1]

I’m reminded that engineers work well in teams ...
thanks

[rlmorel]

Thanks for starting this thread. I have been seeing various people posting something about "750 Rads to the west coast", I have no idea where that came from but it is freaking people out. I just thought I would add this commentary I wrote to another thread, maybe it will help here.

Here is what I said:

Hey. Calm down. Have a seat. I just want to talk to you to help you calm down. There are a lot of things to be concerned about, but there is no reason to get crazy about this 750 RADS thing you hear. There are people out there throwing these numbers around, moving decimal points three ways to one side or another, not realizing they are doing it, mistaking millicuries for curies, Rads for millirems, sieverts for grays, and so on. Look. Don't get crazed. When someone tells you that 750 Rads are going to contaminate an area, it is nonsensical. The units are wrong. It is like telling someone they need a kilometer of flour to bake a loaf of bread. It is nonsensical and irresponsible, because it is scaring the crap out of people.

Here's the thing. A Rad measures the amount of absorbed radiation on something. Not the amount of radiation, but the amount of energy transferred to something, typically human flesh. (note, you may hear someone refer to rads and rems...for the purposes of human flesh and discussion, they both mean about the same thing...so we will just stick to "rads" because that is what you hear out there a lot) Basically, a Rad measures EXPOSURE to radiation.

If you hear someone mention curies, millicuries or megacuries, that is an amount of decays of an isotope in a given amount of time. When you know what the isotope is, and you know how much energy or what kind of energy is given off when that particular isotope decays, then you have an idea how much radiation there will be.

When you know THAT, then you can figure out how much exposure human flesh will get in a given amount of time when exposed to certain levels of that radiation, and that exposure is measured in Rads.

Now. Here is the thing. EVERYONE gets exposure to radiation, and when your tissue absorbs that radiation, you get exposed to a certain amount of rads of radiation. We ALL get exposed. The average annual exposure to the average person living on this planet is 310 millirem. That is very, very small. That is .31 Rads, spread out over a year. Think of it as eating a cup of salt. Would it be bad for you if you took a cup of salt, mixed it in a glass of water and drank it in one minute? You bet it would be bad. But if you eat that cup of salt over the period of a year, you would probably be fine, but if you eat that much all the time, you will probably have cumulative problems from it, right? Radiation is the same. If you get it spread out over time, it isn't that bad, your body fixes it, but a fair amount over time might have cumulative effects.

I worked in nuclear medicine for 15 years, and I was allowed to have up to 5 rads (that is 5,000 mrad, but we refer to it as mrem or a millirem) a year of exposure to my body. I could have a lot more than that to my hands, which I probably did. But I was allowed to get up to 50 Rads (that's 50,000 mrad!!!!) over the course of a year to my hands because you don't have much in your hands that can be damaged by radiation. I am still here. And I worked with people who handled radiation at much higher levels than I did, and they are in their eighties now, without a problem.

The have a measurement they use called the "LD50/30" dose. It means, the amount of radiation (Rads) that a person can get at one time, all in one shot, that will give you a 50% probability of being dead in 30 days. That amount of radiation is about 600 Rads, more or less.

[Nobel_1]

3/13 Morning links and status at Fukushima:

Battle to stabilize earthquake reactors
http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html

Venting at Fukushima Daiichi 3
http://www.world-nuclear-news.org/RS_Venting_at_Fukushima_Daiichi_3_1303111.html

Radiation Falls at Japan Atomic Plant; Explosion Still Possible
http://www.businessweek.com/news/2011-03-13/radiation-falls-at-japan-atomic-plant-explosion-still-possible.html

Fukushima Daiichi Unit 1 (1971)
- Automatically shut down during quake; station blackout following tsunami
- Pressure release implemented; steam and hydrogen explosion after pressures hit 840 kPa / 122 psi
- Primary containment believed intact; seawater and boric acid injection continues
- Radiation levels did not rise after explosion, and are currently below regulatory limits

Fukushima Daiichi Unit 2 (1974)
- Automatically shut down during quake; station blackout following tsunami
- Water level lower but steady; Preparations for pressure release

Fukushima Daiichi Unit 3 (1976)
- Automatically shut down during quake; station blackout following tsunami
- High pressure injection system failed; Pressure releases have started
- Injection of fresh water and boron; Seawater injection started
- Potential for steam and hydrogen explosion, similar to Unit 1

Fukushima Daiichi Units 4,5,6 (1978-1979) – all shutdown prior to earthquake for inspection

Fukushima Daini Unit 1 (1982)
- Automatically shut down; offsite power available following tsunami
- Water level stable; Preparations for pressure release
- Failure of make-up water condensate system

Fukushima Daini Unit 2 (1984)
- Automatically shut down; offsite power available following tsunami
- Water level stable; Preparations for pressure release

Fukushima Daini Unit 3 (1985)
- Automatically shut down; offsite power available following tsunami
- Water level stable; Preparations for pressure release

Fukushima Daini Unit 4 (1987)
- Automatically shut down; offsite power available following tsunami
- Water level stable; Preparations for pressure release

Station Blackout Risk - “It’s considered to be extremely unlikely, but the station blackout has been one of the great concerns for decades,” he told reporters on a conference call. “We are in uncharted territory. We are in the land where probability says we shouldn’t be and we are hoping that all of the barriers to release of radioactivity will not fail.”

Radioactive cesium, a product of atomic fission, was detected near the site yesterday, indicating a meltdown may have begun, said Yuji Kakizaki, a spokesman for the Nuclear and Industrial Safety Agency.

Tokyo Electric began injecting sea water and boric acid to cool its Fukushima Dai-Ichi No. 1 reactor, according to a statement today. The plant’s No. 3 reactor has been vented to release pressurized gas after its cooling system failed, spokesman Akitsuka Kobayashi said earlier.

The “likelihood of success should be fairly high,” Dale Klein, a professor of nuclear engineering at the University of Texas at Austin and former chairman of the U.S. Nuclear Regulatory Commission, said of the seawater flooding. “This should have been part of their overall strategy to keep the core covered and cooled.”

[Springfield Reformer]

The 750 Rads came from some graphic that was posted a few hours after the emergency began. I have no idea who created it but I did see it; they had, like a weather map, charted the projected “fallout zones,” assuming a giant plume of big, uniform areas that managed to catch the Jet Stream and dump uniformly hot particulates on every square inch of the West Coast. The first thing that occurred to me was how no plume model I’ve ever seen for a reactor accident would support anything remotely like that kind of absolute, cartoon-like continuity of emission strength over thousands of miles. Ridiculous.

[Cvengr]

ping

[rlmorel]

I have heard a variety of posters say it on FR that the environazi left are deliberately generating this panic, and I think those people are correct, the scummy bastards on the left are pulling out all the stops, resorting to agitprop. This was likely from a leftist group with a bunch of moonbats, who just make this crap up, and with the power of a computer, can generate a graphic like that which looks...well...real.

Never let a crisis go to waste...the scummy, immoral bastards. They don’t give a rat’s ass how much angst, panic or anguish they cause as long as it suits their leftist purposes.

Man, they piss me off.

[Nobel_1]

Re: March 13 2:30pm EDT update

http://www.world-nuclear-news.org/RS_Venting_at_Fukushima_Daiichi_3_1303111.html

Fukushima Daiichi 1 - unit is now considered stable, with a normal internal pressure of 353 kPa (51 psi), following seawater injection

Fukushima Daiichi 2 - The normal reactor core isolation cooling system is in use. Fuel rods are covered by about 3.8 meters of water.

Fukushima Daiichi 3 - seawater injection continues; a key water level gauge may be malfunctioning. The gauge in question reads that water levels are around two metres below the top of the nuclear fuel assemblies, which would represent a very serious situation with the risk of fuel damage. Pressure levels have come down from 400 kPa to 250 kPa (36 psi), far less than what was seen in Unit 1 (122 psi) before the explosion.

[REDWOOD99]

So what the heck am I gonna do with all of these Iodine tablets?

[Nobel_1]

Re: Analysis following explosion at Unit 3

http://www.world-nuclear-news.org/RS_Explosion_rocks_third_Fukushima_reactor_1402111.html

- containment structure appears intact after the explosion
- pressures were below the reference level of 400 kPa
- Radiation readings on site remained low after the blast, albeit elevated from normal operation. In the service hall the reading was 50 microSieverts per hour. At the entrance to the plant the figure was 20 microSieverts per hour.

The containment structures were designed to manage a full core meltdown with no radiation release to the environment. Recommended reading for those who want to research the engineering side of these 40 year old reactors is at the URL below:

http://www.freerepublic.com/focus/f-bloggers/2688108/posts

[Nobel_1]

Additional cold shutdowns Announced at Fukushima Daini

URL http://www.world-nuclear-news.org/RS_Cold_shutdowns_at_Fukushima_Daini_1403112.html