This week TEPCO workers have been working to remove debris from the top of the Unit 3 reactor building, clearing the way to begin construction of additional protective covering structures and eventual removal of the spent fuel assemblies.
On February 6th, workers started operations targeting a steel truss which was precariously angled across the top of the spent fuel pool around 10:37 in the morning. Two and a half hours into the operation around 13:01, the steel truss broke into two pieces, delaying the extraction process over an hour. The radiation levels near the upper part of the spent fuel pool where the debris removal work was carried out was reported to be between 21.3 mSvh/hr and 25.6 mSv/hr.
After the steel truss operation was completed, workers noted that the fuel handling mast, a 1.5 ton extendable pole used to lift the grip up and down when moving fuel assemblies had disappeared and likely sunk into the spent fuel pool.
TEPCO announced that it would conduct an investigation of the spent fuel pool using a remote-controlled camera to look for visible damage to the spent fuel pool or assemblies, and the current location and distribution of the debris on top of the spent fuel racks.