November 26, 2021

A section of the frozen wall at Fukushima Daiichi has melted. The portion south of unit 4 has had problems remaining fully frozen for years. Now TEPCO admits it has melted in recent weeks. This portion of the frozen wall has had issues for years. Recent changes to the nearby K drainage tunnel and a recently discovered crack may be redirecting water from an underground stream into the area of the frozen wall.

TEPCO found sections near the surface of the wall had fully melted. Puddled water was found nearby. The section is relatively small and didn’t impact the lower depths of the wall’s integrity.

TEPCO’s solution is to install steel piling sections between the K drainage canal and this section of the wall, hoping to deflect underground water. This steel wall will not be completely solid. Due to the nature of driving pilings into the ground, there could be gaps as wide as 10 cm.

Once the pilings are installed, TEPCO plans to monitor the area to make sure the problem has been resolved.

https://www3.nhk.or.jp/nhkworld/en/news/20211126_16/