Highest CAMS readings for Unit 3 D/W on 3/14... that's when the explosion happened in Unit 3. There was a speculation regarding this explosion by TCups. I'd love to hear his comments on this, because I'm not sure if the speculations I'll citing are still up to date... ^^;
So if I remember correctly, he assumed that the explosion could have happened inside the containment and below the SFP. The resulting shock- and heatwave would then pierce the SFP, boil the water away and wreck havoc on everything inside the pool.
If that's what really happened in Unit 4 - wouldn't it be possible that leftover fuel debris is flowing back through the crack in the bottom INSIDE the containment? Then the high radiation readings wouldn't belong to molten core fuel, but to pulverized spent fool.
Which's washed out during the water spraying and pumping activities over the next weeks.
As stated above - TCups, I'd love to hear your opinion about this.