APR: your source for nuclear news and analysis since April 16, 2010

Sunday, April 3, 2011

Sunday morning update: Fukushima Daiichi

As of 5:55 AM Eastern time Sunday, here are the updates...

TEPCO has reduced the amount of water being injected to the reactor cores at No. 1 and No. 2 plants since, as it says, "temperature and pressure seem to have atsbilized on these plants." We don't have adjusted flow rate figures yet, but probably will. This surely is tied to the effort to reduce water flow into the ocean.

Now a word about that... if we want to begin to assign fault for some very specific details of the accident, we might want to blame some of the serious release of radioactivity to the environment to the concrete having cracked outside the plant. However, that would be very easy and probably wrong. Radioactive water should never have gotten out there in the first place--- the cable pits by the intake screens are not a part of the "lines of defense" considered in containment of fission products. While it's true that this has helped make the accident overall somewhat worse, it's important to note that the real problem is far upstream in the flow of that contaminated water. We can't expect that area to hold as a containment barrier.

Speaking of which... the attempt to seal the crack with concrete (No. 2 plant, by the way is the culprit here) failed because the flow rate of water into the pit was enough to prevent the concrete from curing. A synthetic polymer will be tried today.

The core water injection pumps are now receiving offsite power. The press release isn't clear as to whether these are the same temporary pumps used prior to this with temporary diesel generators, or whether these are pumps internal to the plants.

Two barges worth of water have now been brought on site, supplied by the US Navy.

Lights are now on in some parts of some of the auxiliary buildings on site.

Now to the worst news of the day. There have been reports off and on, since March 11 and not necessarily repeated in every press release, that two workers were missing from the site -- they had been there prior to the accident but were not mustered with the crews on-site afterward. Their bodies have now been found in an electrical equipment panel space in the No. 4 plant turbine building. Press releases are saying that these are the first reported deaths on site, but this author recalls that one person was reported killed in a crane operating cab on the exhaust stack of one of the plants on the very first day, so at this point it appears that the death toll on site of TEPCO employees is now actually three.

5:55 AM Eastern Sunday 4/3
ATOMIC POWER REVIEW

UPDATE 6:30 AM: It appears TEPCO is having trouble getting the polymer to plug the cable ways, and is adding sawdust and shredded newspaper. Further, it now looks like there are TWO separate release paths; the path that the water is getting to the cable pits through encloses only the cable runs and is not a cross connection with the pipe trenches.

10 comments:

  1. Congratulations on your site. It is the only site I can find that gives a sensible account of what is going on. I would like to comment on the blame game. In relation to the operators, on the day of the quake they felt the unbelievable force of the quake then saw a 14m tsunami pass by. Can you imagine what was going through rheir minds. I assume they live in the region and would be wondering if their children, families and friends had been killed. They would have been traumatized and torn between saving the plant and finding their loved ones. I am sure they are still working under incredible personal stress. There must be a case for outside international relief teams for this type of situation.

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  2. Will,

    Tepco says "temperature and pressure seem to have stabilized on these plants."

    But there is very weird pressure reading for unit 1 RP (b). It is going up and is now at 643 MPa while RP (a) pressure is going down.

    Check here: http://www.gyldengrisgaard.dk/fukmon/uni1_monitor.html

    This has me concerned for quite a while now. The last thing we would need now is another reactor vessel blowing apart.

    Do you have any idea of where RP (a) and (b) are measured or how to explain the divergence?

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  3. It would be interesting to know where the sealant injection point is and what limitations there are on the material injected. Are they going to have sawdust and newspaper flowing thru the core? Presumably yes or they would be injecting a sealant that can set. Cement for example will set at the boundary even if there is a flow if you are pouring concrete but it can never be sealed if only water moves thru setting concrete. Newspaper will blow out at the downstream end if pressurised.

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  4. Just sent you mail with a graph and questions about no 1.

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  5. cracks in concrete amuze me. are they because of earthquake or the seawater that was used for cooling?

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  6. Yes, the crack(s) in the trench should not be mistaken for the source of the radioactive leakages. Good point.

    There is no doubt, incidentally, that the three workers killed on site were killed directly by the earthquake/tsunami. This is not especially surprising given that the death toll from the tsunami along that coast is over 10 thousand. Their deaths are nothing to do with nuclear power.

    The injuries due to the hydrogen explosions are reasonably attributable to nuclear power.

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  7. Will, our local paper, the Herald ran this today: http://www.miamiherald.com/2011/04/02/2147780/if-the-worst-happened-is-there.html

    I did chime in as I lived near this nuke plant during Andrew and we never had any issues. I also linked to your blog and asked people to educate themselves on this issue. I have found your blog to be most interesting and a great source of information.

    Mike

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  8. My interpretation of no 1 data:

    http://www.moonofalabama.org/2011/04/fukushima-no-1-data-interpretation.html

    Please let me know your thoughts on it.

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  9. Thanks to everyone for writing!

    @b - the pressure of .632 mPa is only 92 psig and since these plants operate around 1000 psig and 545F steaming I don't think this pressure rise is serious. In fact, as a number of experienced nuclear engineers have emailed me, it sure looks like at No. 1 plant the core is guaranteed still in the pressure vessel considering the high feed nozzle temperatures we're seeing.

    @joffan: Very well said. All three men were killed by the tsunami, not the nuclear accident.

    Thank you very much Rob, and Mike.

    @machlipatnam: Certainly the quake / tsunami caused these cracks in the concrete.

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  10. Thanks Will
    - that increases the safety margin. But it doesn't explain the pressure differences. I'll keep wondering what is going on in there.

    Thanks for your help.

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