The team, made up of officials from Toshiba and the US National Los Alamos Laboratory, showed the device to the media on Friday.
Studies are underway at the damaged plant to locate the melted fuel at 3 reactors using muons.
The new device uses muon detectors, each measuring 8 by 8 meters. The detectors will observe how the courses of the particles change before and after they pass through the reactors, and use that to visualize the substances inside.
Two devices will be installed for the No. 2 reactor, one on each side of it, later in the year.
The team says the resolution offered by the device is expected to be more than 3 times that of the equipment that has been used by a Japanese institution to scan the No.1 reactor.
The institution said earlier this month that its scan, which uses only one small detector, found almost no nuclear fuel inside the No.1 reactor core. That suggests that the fuel fell into the containment vessel.
Toshiba official Haruo Miyadera says the new device will help scientists discover details on the location and amount of the melted fuel, and come up with ways to take it out.
Filed under: 8.Eathquake & Nuclear accident