An incineration facility to dispose of wood contaminated with radioactive substances has been completed at the Fukushima Daiichi nuclear power plant.

The 2011 nuclear accident at the plant led to the dispersal of radioactive substances, contaminating the reactor buildings as well as other buildings and roads at the facility.

The operator of the damaged nuclear power plant in Fukushima, northeastern Japan, plans to build a taller seawall to help protect against future high seismic sea waves.

The move comes in response to the projection made in April by a government panel on the scale of tsunami that could be triggered by a massive quake along the Japan Trench in the deep sea off northeastern Japan.

Tokyo Electric Power Company plans to draw up safety measures for workers after finding that some of the buildings at the Fukushima Daiichi nuclear plant are in bad condition due to the 2011 accident.

TEPCO on Monday reported to the Nuclear Regulation Authority the results of its survey of about 580 buildings in the compound.

Japan's nuclear regulator says radiation levels around the crippled Fukushima Daiichi nuclear power plant have decreased to about a quarter of 2011 levels.

The Nuclear Regulation Authority says radiation levels recorded last September fell by about 78 percent compared to levels recorded in October 2011. Data was compiled in almost identical circumstances on both occasions.