in august, tepco began considering changing the core injection method for the no. 3 reactor as it required a much larger quantity of water to cool and the temperatures remained relatively high compared to the nos. 1 and 2 reactors which required far less water. tepco has hypothesized that this may be because some fuel is still present above the core support plate inside the pressure vessel of the no. 3 reactor in addition to the fuel that has fallen to the bottom of the pressure vessel. the fuel on the bottom would be easily cooled by the existing method, but as the pressure vessel is leaking, any fuel located on the support plate was likely only being cooled due to the steam generated by the cooling of the melted fuel at the bottom. tepco began considering utilizing the reactor's core spray system pipes as an additional path of water injection and then reduce the amount of water through the existing feedwater piping system. a team of workers were sent inside the reactor building to inspect the core spray system pipes, and it was found that the piping was undamaged. hoses were then run from the temporary injection pumps located outside the building and connected to the core spray system piping. on 1 september, tepco began injecting water using the new route. the new injection method has been considerably more effective in lowering the temperature of the reactor to below 100 degrees celsius. as of 27 september, most of the no. 3 reactor's temperature readings are between 70–80 degrees celsius. later, tepco began utilizing the same method in the no. 2 reactor; it has not had as significant effect on the no. 2 reactor as it did on the no. 3.