the next day at 7:55 a.m. the steam was gone. because the radiation levels were too high all work to remove rubble was done by remote control. operations stopped after the steam was found. according to tepco the rain on 17 and 18 july was to blame. on 18 july the actual dosage measurement was 562 millisieverts per hour, therefore the nra ordered tepco to make further investigations. on 23 july at 9:05 the steam was seen again coming out of the fifth floor just above the reactor containment. the night before a rain shower did hit the building, and water might have reached the - 38c - reactor container lid, or might have reached hot fuel left behind in the reactor vessel. at that moment, the ambient temperature was 20.3 c, and the humidity was 91.2 percent. all work removing rubble from the place was halted. during the last event, radiation levels were measured at 24 locations around the fifth floor of the reactor building. the dosage ranged between 137 millisieverts and 2,170 millisieverts per hour.