We do not have any idea to what extent various fuel elements were damaged. So far isotopics suggest that Cs 137 and I131 were the main issues, but these are highly volatile products. The existence of longer lived fission products would be necessary to conclude that there was a significant breach of reactor containment.
Was watching the Japanese English news earlier this morning and they claim that the highly radioactive puddles of water could have leaked just from a valve or pipe going into the reactor. So we could just have a broken valve or pipe going to or from the reactor vessel. Those radioactive puddles contaminated three workers after they stood in a 5 inch deep puddle of water. According to English Japanese reports.