Tokyo Electric Power Company is continuing work to reinforce a spent fuel pool at the Number 4 reactor of the Fukushima Daiichi nuclear power plant.

The walls supporting the pool were heavily damaged by a hydrogen blast on March 15th, following the earthquake and tsunami 4 days earlier.

The pool contains 1,535 spent fuel rods and its weakened structure makes it vulnerable to future earthquakes.

TEPCO on Monday completed one stage of the reinforcement that began late last month. 32 iron pillars, each 8 meters tall and weighing 40 tons, were installed beneath the pool on the 2nd floor of the reactor building.