I hadn't seen this reported until today:
TEPCO urged to probe troubled projects at plant http://www3.nhk.or.jp/nhkworld/english/news/20150323_37.htmlThis plan to pour cement into flooded tunnels explains the large number of cement trucks I've seen on the futaba cam recently. I bet the process of dumping the cement into hot-radioactive water produces the heavy-looking steam I've seen recently hanging over units 1-3
Mar. 23, 2015 - Updated 06:10 UTC-7 Japan's Board of Audit says the operator of the damaged Fukushima Daiichi nuclear plant needs to seek compensation from companies that engaged in failed projects to reduce the buildup of contaminated water at the plant.
The Board of Audit has pointed out for the first time issues related to Tokyo Electric Power Company's spending on dealing with the contaminated water.
The Board mentioned one of TEPCO's projects. The utility once tried to freeze contaminated water in underground tunnels to stop the inflow of highly radioactive water from reactor buildings. But the plan failed, and TEPCO officials adopted a method of pouring cement into the flooded tunnels.