So reported NHK World on Wednesday, here:
Tokyo Electric Power Company analyzed the changes in pressure levels inside the pressure and containment vessels to gauge the scope of the damage.
TEPCO said the analyses show that holes in the Number 1 reactor containment vessel amounting to 3 centimeters in total may have formed 18 hours after the quake. ...
The utility said holes and cracks equivalent to 10 centimeters in diameter may have formed in the Number 2 reactor's containment vessel about 21 hours after the quake. ...
TEPCO said these results were obtained through data calculations, and that it has yet to confirm whether such holes actually exist.
Presumably high radiation conditions near the reactors continue to prohibit the actual physical inspections which would confirm such estimates and calculations.
