Basement pumping work delayed

31 March 2011

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.

Reactor-by-reactor, system-by-system summary from JAIF on 31 March
Reactor-by-reactor, system-by-system summary from JAIF on 31 March; yellow indicates abnormal/unstable; red means damaged/nonfunctional/unsafe

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

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