Here I thought they'd been injecting water directly above the melted fuel or where the fuel had once been.
TEPCO in its daily press conference on July 26 said the cooling of the three reactors at Fukushima I Nuclear Power Plant has been done by cooling the core shrouds from outside. The shroud is a cylinder inside the Reactor Pressure Vessel (RPV) that surrounds the reactor core. (The image is from Toshiba.)
Either they tell us now, or it occurred to no one to ask in detail how the fuel was cooled.
Mainichi Shinbun Japanese (7/26/2011):
TEPCO announced on July 26 that the company started the work to change the method of water injection in order to cool the fuel inside the Reactor 3 more effectively. The Japanese-made robot "Quince" went inside the reactor building to investigate whether it was possible to use the pipe that could feed water closer to the nuclear fuel.
In Reactors 1, 2 and 3, the cooling water is being poured outside the core shroud to lower the temperature of the fuel. The method is adequate in Reactor 1 and 2 with about 4 tonnes/hour water injection, but in Reactor 3 this method of cooling is not efficient enough, and it requires 9 tonnes/hour water.
しかし、その分、汚染水が大量発生しやすく、新たな対応が必要になってきた。そこで、東電は核燃料の真上から注水する緊急炉心冷却装置 （ＥＣＣＳ）の配管などを使うことを検討。同日、建屋１、２階にクインスを入れ配管を撮影したほか、作業員が入れるかどうか周辺の放射線量の測定を始め た。
As the result, more contaminated water is being produced, and the company was looking for an alternative method of cooling. TEPCO is considering using the ECCS (emergency core cooling system) pipe which can pour water from above the fuel. On July 26, the company sent the robot "Quince" to the 1st and 2nd floors of Reactor 3 building to take pictures of the pipe, and started measuring the radiation levels to see if workers could enter the building.
As far as TEPCO is concerned, the melted core is still inside the RPV in Reactor 3.