Samy24 said:
As I have learned the "skimmer level" is not the water level in the SFP
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110418e5.pdf"
The temperature is rising since the last days, but is still lower than the highest readings in the past. So maybe it does not explode by now ;)
Yes skimmer surge tank and SFP communicate through their upper part, and FPC skimmer level does not give SFP level. However, it gives an indication on the moments the SFP is full, and whether a water injection or spray fills in the pool or not.
If FPC skimmer level increases, it means water has overflowed from the SFP, and thus that the SFP was full during the previous water injection / spray.
Amount of water added between two "SFP full" signals gives an estimate of the amount of its losses between those two signals.
Second indication is given when dealing with temperature. The only reported SFP temperature is that of SFP2. Temperature increases with skimmer level. Temperature of the SFP seems to be measured in the FPC skimmer. When SFP overflows, water coming from it flows in FPC skimmer, mixing with water already there. One could deduce temperature in SFP, when we have temperature and level before and after overflow.
Now what does it tell us for the various SFP ?
SFP1: skimmer level has never raised, even when Tepco performed the (only reported) refill on Mar 31st (90 tons). We have no proof by this measurement that SFP1 has enough water. We can wonder how Tepco follows SFP1 (absence of steam above SFP1 ?).
SFP2: we have 9 signals showing that SFP was full (between brackets the tons of water required to get "full" signal again, followed by the caculated loss rate [tons per day])
- 01/04/2011 17:05
- 04/04/2011 13:37 (70 => 24.5)
- 10/04/2011 12:38 (96 => 16.1)
- 13/04/2011 14:55 (60 => 19.3)
- 16/04/2011 11:54 (45 => 15.6)
- 19/04/2011 17:28 (47 => 14.5)
- 22/04/2011 17:40 (50 => 16.6)
- 25/04/2011 11:18 (38 => 13.9)
- 28/04/2011 11:28 (43 => 14.3)
SFP2 seems basically quite full all the time. Its max loss in this period is 96 tons, which is roughly only 6% of it. SFP2 level seems under control. What about temperature ? For example, for the last "full" event (28/04/2011 11:28), level before overflow was 5400 (millimiters in skimmer) and temp was 50°C. After it, was 6000 and 71. What was the temperature of the added Water, assuming FPC skimmer is of cylinder form ? Well FPC skimmer 2 has leaks, which are about 400 millimeters per day.
So at the exact end of injection, level could have been 6400. Well my own calculation shows water temperature above boiling point ... Any clue to calculate this ? Any info on FPC skimmer form and dimensions ?
SFP3: we have no report of FPC skimmer level. The only information is that they have added at least 1000 tons of water to it since beg. of earthquake. For SFP3 also we can wonder how they monitor the level of it (and temperature).
SFP4: we have only 4 signals (same reporting than SFP2):
- 13/04/2011 06:57 (prior to this: about 1550 tons injected / sprayed)
- 15/04/2011 18:29 (140 => 56.4)
- 17/04/2011 21:22 (140 => 66)
- 27/04/2011 14:44 (1210 => 124)
SFP4 has important losses. Simply by boiling, SFP4 would lose max 71 tons per day. The last figure tells us that SFP4 leaks, and is capable to leak importantly (53 tons per day in some circonstances). One important fact is that losses became accelerating since Apr. 17th. The most problematic is that I do not see any refill since the 27/04/2011 14:44; extrapolating this could mean SFP4 has left about 570 tons since then, roughly 1/3 of its height (assuming gate is still there ...). When was the video showing SPF4 underwater was taken ?
