So the Japanese PM has ordered TEPCO to close all of the nuclear reactors at Fukushima and concentrate on cleaning up the radioactive water:

Japanese authorities ignored US calls to contain contaminated water at the stricken Fukushima power plant in 2008, officials told media. The revelation comes as the Japanese battle to stem radioactive water leaks flooding into the sea from the facility.

Tokyo Electric Power (TEPCO) estimates that 300 metric tons of groundwater has mixed with radioactive material at the site and is steadily flowing out to sea. Water needs to be constantly pumped over the stricken reactors at the Fukushima site to prevent them from overheating.

Four hundred metric tons of groundwater runs into the nuclear facility from higher ground every day, TEPCO estimates. Japanese authorities have so far been unable to stem the flow, although it turns out they were aware of the threat groundwater posed back in 2011 in the wake of the tsunami that decimated the facility.

Two officials dealing with the cleanup operation told Reuters that TEPCO had ignored warnings from US experts over the need to control contaminated water at the site. A plan to construct a barrier to prevent the groundwater from entering Fukushima was proposed as early as April 2011.

“It was obvious to us that there was great deal of groundwater intrusion into the plant, and we shared that with the Japanese government,” said Charles Casto, a representative of the US Nuclear Regulatory Commission (NRC) who was based in Tokyo from March 2011 to early 2012.

TEPCO chose to disregard the idea because the potential cost of constructing the barrier would have had an impact on investor confidence. A TEPCO memo obtained by Reuters that was sent to Japanese officials in June 2011 said the expense of constructing a barrier would fuel fears of imminent bankruptcy.

"Cost wasn't the only reason for not moving ahead," said Yoshikazu Nagai, a spokesman for TEPCO.

"The wall raised a number of technical questions that made it unclear whether it was feasible. For that reason, there was concern that it would be recognized as a liability and push the company closer to insolvency," said Nagai, adding that levels of radiation were still too high at the site to begin construction so soon.

Japanese Prime Minister Shinzo Abe visited the Fukushima plant on Thursday and ordered the two nuclear reactors at the site, which were not damaged by the 2011 quake, to be decommissioned. He also stood by his earlier pledges and said the area would be safe and stable in time for the 2020 Olympics in Tokyo.