The latest on the progress (or lack thereof) of TEPCO's tragi-comical effort to freeze highly contaminated water in the trench leading from the Reactor 2 turbine building (see my post on 7/28/2014 for details) is that the pipe they've been using to dump ice and dry ice got clogged with dry ice. TEPCO admits there has been no discernible effect of ice/dry ice on freezing the water.
So what's your Plan C?
From TV Asahi News (8/12/2014; part):
Fukushima I NPP: TEPCO plays its "ace", which ends up clogging the pipe
It has been revealed that dry ice, which is being poured [into the freezing pipe] as the surest bet to freeze the water in the underground trench as part of the measures to deal with contaminated water at Fukushima I Nuclear Power Plant, has had no effect.
The national government and TEPCO have been trying to freeze the highly contaminated water in the underground trench by installing a metal pipe and pouring liquid coolant through the pipe [since April this year]. But as the effort has failed to freeze the water, TEPCO has started to pour ice since July 30. Total 222 tonnes of ice have been poured into the pipe as of the morning of August 11. In the press conference on August 11, TEPCO said the effect [of ice] in freezing the contaminated water was "unknown", admitting that there was no discernible effect. Further, when they tried to pour in 1 tonne of dry ice on August 7 as the "surest bet" to freeze the water, it clogged up the pipe. TEPCO has halted the pouring of dry ice.
The pipe through which workers have been dumping ice and dry ice (from TEPCO's photos and videos library 7/24/2014):
The pipe (in purple color) in the diagram:
I am grateful for the news, because it gave me the first laughter of the day. Laughing is good for one's health, I hear (regardless of the topic, I hope).