Le blog de fukushima-is-still-news

April 27, 2018

Fresh analysis of Fukushima Daiichi 'fuel debris'

https://www3.nhk.or.jp/nhkworld/en/news/20180427_02/

A fresh video analysis by the operator of the Fukushima Daiichi nuclear power plant shows that molten fuel at the No.2 reactor may have fallen along several paths. The unit is one of the 3 reactors that experienced a meltdown in 2011.

Tokyo Electric Power Company processed images that were taken inside the reactor's containment vessel in January. The firm pieced them together so that the resulting footage can better show conditions within the entire vessel.

The footage shows all of the vessel's bottom covered with what looks like pebbles and clay. A roughly 70-centimeter-high pile of such materials is located near where part of the fuel casing was spotted in the January probe.

Another heap is close to a pillar-like structure at the bottom.

The utility says the materials may be fuel debris, which is a mixture of molten nuclear fuel and structural parts.

The firm also released a 3-dimensional video that reconstructs the interior of the containment vessel of the No.3 reactor. The unit also suffered from a meltdown.

The footage shows a mound of materials near the center of the vessel's bottom. The company says it may have emerged after fuel debris fell onto structural parts that had already dropped there during the 2011 accident.

The utility says the new images provide clues to determine the paths along which molten fuel fell. It plans to decide in the next fiscal year how to remove the fuel debris.

The company is seeking to remove the molten fuel as part of its effort to decommission the plant.