Tokyo Electric Power Company Holdings Inc. (Tepco) found no obstacles Wednesday to its planned removal of radioactive fuel rods from a spent fuel pool at the Fukushima No.1 nuclear power plant, the firm has said.
Tepco confirmed the findings after starting its first internal probe of the No. 2 reactor since the 2011 disaster. The investigation is expected to continue through Friday.
Using a remotely operated underwater robot to photograph the interior of the pool, submerged fuel rods and their storage racks were checked for any damage. A total of 615 spent and unspent fuel rods are stored in the pool.
White sediment was discovered on the aluminum alloy racks. It is believed to have formed from a reaction between aluminum and elements in sea water, which was injected into the pool to cool the nuclear fuel during the disaster.
Similar sediment was found in the reactor pools at units No. 3 and No. 4, from which fuel rods have already been removed, but according to Tepco it did not affect the process.
Similar to the No. 1 and No. 3 reactors, the No. 2 reactor suffered a core meltdown after it temporarily lost its cooling function in its spent fuel pool, but there was no hydrogen explosion at the building.
Because of that, the pool is thought to be free of debris and in a relatively stable condition.
High radiation levels on the top floor of the reactor building, where the fuel rods are located, have delayed cleanup efforts.
But progress in decontamination efforts has now enabled remote inspections to be carried out.
A new facility complete with a crane and equipment to lift out the fuel rods will be built on the south side of the No. 2 nuclear reactor building. The removal process is slated to begin sometime between fiscal 2024 and 2026.