elektrownik said:
What ? Unit 6 reactor building is floded ? How ?? I understand turbine building from tsunami, but reactor building ?
And 2m of water in unit 6 turbine building... But how, unit 5 turbine building is not so floaded like 6...
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110531e19.pdf <- radiation data from unit 4 and 2 sfp
You are very right, this is amazing...
Until now we heard that Tepco was pumping some water out of TURBINE building of N°5 and 6, an operation that whas explained to be already conducted as routine before the tsunami but stopped because of the tsunami, and then started again. We concluded that these T/B must haven been under groundwater and that they were obliged to pump to keep them dry, and that maybe this has to be increased because of groundwater increased level due to tsunami (this was an hypothesis). So normally, nothing really bad...
But on this map, it appears that there is water also in basements of reactors buildings N°5 and N°6, in areas that are important for safety because that's were a lot of the alternate cooling systems are! (I remember that N°5 and N°6 were stopped for maintenance if not wrong... fortunately! otherwise they couldn't probably maintain this cooling over time switching between SFP and reactor...)
This is typically some "Tepco language": if you look at Units 1 to 6, the documents indicate each and every time T/B which is Turbine Building, but they show maps for T/B AND R/B.
Then when they indicate that there is "100m3 total in T/B" for N°5 and "4000m3 in T/B" for N°6, what do we have to understand?
Until now we understood something very stupid: "4000m3 in T/B" was meaning for us, stupid guys with no Tepco language knowledge, that this water was in... Turbine Building of course! But in fact, where is it? It shows R/B and T/B, but with this title: "Accumulated water map in Unit X T/B"!
Let's play dices to decide what to interpret...
The big question is really to know how this water got there,
in an area that is CRITICAL for safety control of the reactors :
A)
If this water comes from the tsunami, this is very scary, because this means that there could have been a problem with cooling system failure even without power black out, due to flooded equipement in R/B.
B)
If this water doesn't come from tsunami, then where does it come from? From underground water? This is scary again with safety equipements here. From reactor leaking??? Was it damaged during earthquake as a matter of fact?
Is it related to what we mentionned some weeks ago already in the parameters for Unit 5 and 6, where the water levels are always varying in the core?
Personnaly i still think this can be explained by the alternate system for cooling which if i understand well has to be switched between two things, SFP and reactor (correct me if wrong), creating this pattern with teeth in Temps, and also possibly explaining water level variation by more or less evaporation inside the core. But maybe this intrusion of water in R/B is an explanation why some cooling systems are not fully operational?
Again, this raises a lot of questions and mysteries. This is not what i would call a "normal" cold shutdown.
This brings also the questions of general safety, even "beyond design basis" which is the nice way engineers use to describe mess they didn't anticipate... We were talking about placing some critical equipement at a suffcient height to avoid flooding, but what about these electrical systems that are it seems now in R/B rooms with substantial level of water in them (and they pumped already good volumes!). What are they going to do to change the design to avoid flooding possibilities of these areas?
I've found surprising, to say the least, one image released by Tepco some weeks ago, showing many many tanks to store the "basement" water close to N°5 and N°6: huuuuhhh, so many tanks? If i find it I'll post it...
I think there is a new mystery in this Daichi plant, with these N°5 and N°6 reactors, where I suspect there is more than assumed. AGAIN.
