TEPCO workers sent an underwater camera into the Unit 3 spent fuel pool to determine the final resting place of the fuel handling machine mast, which was knocked into the Unit 3 spent fuel pool during debris removal operations on February 6th, 2013.
The 1.5 ton device was found resting on top of the fuel racks, where it apparently narrowly avoided striking and damaging the liner of the spent fuel pool. The utility did not release any data related to measurements of radioactive materials in the spent fuel pool which would likely show an increase if spent fuel assemblies had been damaged.
Source: TEPCO
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