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Tuesday, May 10, 2011

Fukushima Daiichi updates

As work at the site really gets heavy in all areas of restoration, the news is beginninng to come out of Fukushima Daiichi fairly rapidly. Here are some of the most important updates I've seen.

-TEPCO has released a video of the spent fuel pool at No. 3 plant showing massive amounts of building debris in the pool. The debris includes steel I-beams, concrete and building material rubble, and masses of reinforcing iron bars as well as cables and other miscellaneous material. In fact, it's practically impossible in the video released to make any estimation of spent fuel condition because you can't see it.

-TEPCO indicates that calibration of water level indicating equipment at No. 1 plant is underway, in the effort to get the active fuel region covered with water. Contrary to some assertions elsewhere on the Internet, there is still apparently no direct flowpath THROUGH the fuel region of the reactor since injected cooling water is running down the outside of the core barrel to the egress points at the jet pump standpipes... if the TEPCO information about the actual feed injection point up until now remains valid (ie, the feed ring.) This allows heat removal from the core barrel, which itself is transferring heat from the fuel. However, the new plan is to raise water level in the dry well above that of the jet pump standpipes which will then allow internal level (inside the core barrel) above them as well. New feed into the core barrel will be established, along with the feed through the normal sparger ring as up to now. We published that drawing (for the new arrangement with dry well filled) a while back on this blog.

-Hampering the efforts however at No. 1 plant is the radiation level. While TEPCO has brought in some lead embedded sheeting, this material (which we understand is more blanket-like than steel plate-like) is not reducing the rad level as much as TEPCO would like in work areas, which has led to the slowing of some efforts.

-Over at No. 3 plant, temperature continues to rise slowly with last report of lower pressure vessel head temperature now at about 151C, up over 30 degrees in a week. TEPCO has now revealed that it altered the flow path for injection water at some point in the past. Temperature has risen slowly over a period of about one month. TEPCO is shifting back to its first injection path for this plant, which it hopes to be using by Thursday. We don't have a piping diagram from TEPCO yet to illustrate the change in flow path.

More details as they're available.

11:00 AM Eastern Tuesday 5/10
ATOMIC POWER REVIEW

1 comment:

  1. TEPCO says it was able to get workers into the second floor of the reactor 1 building and that it believes work on the new cooling system can start:
    http://www.yomiuri.co.jp/dy/national/T110509004352.htm

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