Environment & Energy

FBaggins

(26,800 posts) Fri Jul 8, 2016, 09:30 PM Jul 2016

Possibly no melt-thru at Fukushima Unit #2

June 30, 2016

It appears that most re-solidified fuel (corium) is in the bottom head of unit #2. The Muon detection system at F. Daiichi has found a large, black shadow inside the bottom of the reactor vessel (RPV). Analysis strongly suggests that most, if not all, of the corium pooled inside the bottom head and plated out on other internal structures. Unit #2 is the first one where the Muon detection could see the bottom head of the RPV. This is the first of the three damaged units to have an indication of where the corium ended up. The Muon scan of unit #1 could not see any lower than the core support plenum, so there was no indication of whether or not the corium pooled inside its bottom head. Most researchers speculate that the unit #1 corium melted through the bottom head. http://www3.nhk.or.jp/nhkworld/en/news/20160630_07/

http://www.hiroshimasyndrome.com/fukushima-accident-updates.html

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Possibly no melt-thru at Fukushima Unit #2 (Original Post) FBaggins Jul 2016 OP

Some confirmation FBaggins Jul 2016 #1

FBaggins

(26,800 posts)

1. Some confirmation

Reply to FBaggins (Original post)

Mon Jul 18, 2016, 11:32 AM

Jul 2016

Study shows bulk of fuel still in crippled Fukushima No. 2 reactor

A study on the disaster-hit Fukushima Daiichi nuclear power plant has found that most of the melted fuel in the No. 2 reactor is still present in the reactor core area, sources close to the matter said recently.

According to the study that used a cosmic ray imaging system, around 200 tons of fuel and other melted substances is estimated to have accumulated at the bottom of the pressure vessel, the first time the current location of the fuel has been specified.

The finding is important for devising ways to remove the so-called fuel debris, the most challenging task in decommissioning the Nos. 1 to 3 reactors that suffered meltdowns in the nuclear crisis that began in March 2011.

http://english.kyodonews.jp/news/2016/07/421290.html

That last sentence is somewhat optimistic. Yes, it's a good thing that there does not appear to be significant melt-through of the RPV, but that doesn't mean that it holds water (it clearly doesn't).

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