In the last week there have been a couple of earthquakes which exceeded 6. The earthquake and subsequent tsunami warning stopped the reactor cooling and pumping work which highlighted the temporary nature of the systems providing cooling. Since the prognosis is it will take several months to restore the closed cooling systems, work was done to upgrade the core cooling systems for unmanned operation. The diesel generators were moved to higher grounds and electrical feeds were improved. Fresh water continues to be injected into the Unit 1, 2, and 3 cores. Periodically water is injected into the spent fuel pools to maintain level and cooling.
Recognizing the work and time which will be needed to secure and cleanup Daiichi led to the reclassification Daiichi from a level 5 to 7. Three Mile Island is a level 5 accident and Chernobyl is a level 7 accident. The total radioactivity released by Daiichi will not exceed Chernobyl but because the area around Daiichi has a greater population density the affect on the public is much greater. Additional areas have been evacuated in the last week.
The pumping of water from the Unit 2 reactor building into the condenser was halted by the recent earthquakes but progress has been made. About 900 of the estimated 6000 tons (1.6m gallons) have been pumped to the condenser. They have seen the water level drop, but it is also rose overnight due to leaking of the core cooling injection water into the reactor building.
Some metal plates and sediment fences have been installed at the entrance to intake bay of the plant to reduce the amount of radioactivity which may be getting into the ocean. Normally the intake bay’s flow is into the plant and is used for cooling. The earthquake and tsunami took out the pumps which draw in the water. The highly radioactive water leak which was stopped last week was flowing into the intake bay. The reports on the ocean samples are not showing the decrease in radioactivity from dilution we would expect if there were no additional leakage is occurring from the site.
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