Here's an update on TEPCO's attempts to patch the leak in the cable trench beneath Unit 2 at the Fukushima-1 nuclear complex (from Al Jazeera):

"Japanese officials grappling to end the nuclear crisis at the earthquake and tsunami-damaged Fukushima plant are focusing on a crack in a concrete pit that is leaking highly radioactive water into the ocean from a crippled reactor.

"There have been two attempts now to stem the flow of water from a pit near reactor No. 2," Al Jazeera's Wayne Hay, reporting from Tokyo, said on Sunday.

"In the first they [power plant workers] tried to use cement but that failed, in the second they tried to use a polymeric material, a kind of powder, but at the moment that is not working either," he said.

"Officials at TEPCO [the company that operates the plant] say they are not giving up yet on this product they will test it again on Monday. If it isn't working then, it is not clear what step 3 will be to try and stem the flow of this water.

"But even if they do stop the water flowing out of this pit, the water shouldn't be there in the first place, this is a pit that contains cables, so how do they stop that, that's the next question."

The water has been leaking into the sea from a 20-centimetre crack detected at a pit in the reactor where power cables are stored. TEPCO said the pit is connected to the No. 2 reactor's turbine building and a tunnel-like underground trench, in which highly radioactive water has been spotted so far."

Of course it will also be important to identify the source of the radioactive water that is filling the trench.

TEPCO has finally acknowledged that two plant workers were killed in the initial earthquake and tsunami. Their bodies were recently recovered and decontaminated.

Charley Noble