Washington’s Blog 
January 24, 2012
Fukushima Operator Admits 20% Increase In Radiation
JiJi Press – one of Japan’s largest news sources – reports :
Tokyo Electric Power Co. on Monday reported an increase in radioactive materials leaking from damaged nuclear reactors at the Fukushima … plant.
The total amount of radioactive cesium that leaked from the containment vesselsof the No. 1 to No. 3 reactors reached 70 million becquerels per hour, up 12 million becquerels from the December level, the power firm said.
It seems that radioactive dusts were stirred up because plant workers went inside reactor buildings and removed rubble, TEPCO officials said.
While it is possible that the increased radiation is simply due to dust being stirred up, there is some evidence  that the increase in radiation corresponds with recent earthquakes.
Or it could be due to the possible escape of nuclear fuel from the nuclear container vessels .
Indeed, a Fukushima whistleblower allegedly claims that radioactive fuel is coming out from beneaththe containment building :
These [highly-radioactive] yellow concrete slags come out from under the buildingone after one. It means that the container vessel is melting like honeycomb at least – doesn’t it? Otherwise why would metal uranium comes out of there ?
And see this .