Efforts to clear the radioactive water pooling in the basement of the Fukushima Daiichi units 1, 2, 3 and 4 turbine halls, to restart emergency backup diesel generators, continue to be delayed because of the lack of empty water storage tanks.
Pumping out of water in the basement of unit 1, begun 24 March, ended on in the morning of 29 March when the unit 1 turbine condenser filled up. Japan nuclear regulator NISA said that the basement, now 20cm deep, is half as deep as when pumping began. Based on a pumping rate of 6 m3/hr, NEI magazine estimates that 636 m3 was pumped out.
Turbine condensers at unit 2 and 3 are also full.
Plans to pump the water out of the turbine condensers and into condensate storage water tanks are delayed by the fact that the unit 1, 2 and 3 condensate storage water tanks are also full, according to TEPCO.
Instead, the utility began pumping water from the unit 2 and unit 3 condensate storage water tanks (on 29 March and 28 March) into two suppression pool water surge tanks shared by units 1-4. These latter 3400 ton capacity tanks are about one-third and one-half full as of 10am local time 30 March. As of that time, NEI magazine estimates that less than 500 tons has been pumped from the unit 2 condenser storage tank, and less than 1000 tons from the unit 3 tank, based on the pumping rate and density of water.
TEPCO is preparing to pump water from the unit 1 condensate storage tank to a suppression pool water surge tank, and from the condenser to condensate storage tank, so that it can dry out the unit 1 turbine hall basement. It is also preparing to pump water from unit 2 and 3 turbine condensers to condensate storage tanks, and ultimately from the turbine building to the condenser.
It is also studying how to pump water from a tunnel outside the turbine building that is almost completely full of water into a 25,000 ton-capacity waste disposal facility on site.
FilesReactor-by-reactor, system-by-system summary from JAIF on 1 April Fukushima-Daiichi parameters 1 April