Update Fukushima Nuclear Accident (3 April 2011, 12:00 UTC)

TEPCO has identified a possible leakage path from the Turbine building of Unit 2 to the sea via a series of trenches/tunnels used to provide power to the sea water intake pumps and supply of service water to the reactor and turbine buildings. As of 2nd April 07:25 UTC the pouring of concrete was started in an attempt to stop the water leakage. As of 2nd April 10:15 UTC, pouring of concrete had ceased and no significant decrease in the rate of leakage was observed. There is a plan to inject polymer to attempt to stop the leakage. TEPCO announced on 2nd April that, following the detection of highly contaminated water leaking through a crack found in a pit near Unit 2, they had added 3 additional sampling points at 15km from Fukushima Daiichi and Fukushima Daiini.

Fresh water has been continuously injected into the Reactor Pressure Vessel of Unit 1 through the feed-water line at an indicated flow rate of 8 m3/h using a temporary electric pump with diesel backup. Fresh water is being injected continuously into the RPVs in Units 2 and 3 at indicated rates of 9 m3/h and 7 m3/h respectively through the fire extinguisher lines using temporary electric pumps with diesel backup.

In Unit 1 the indicated temperature at the feed water nozzle of the RPV is relatively stable at 259°C and at the bottom of RPV at 117°C. The RPV pressure indications are fluctuating and Drywell pressure is slightly decreasing. In Unit 2 the indicated temperature at the feed water nozzle of the RPV has decreased slightly from 161°C to 153°C. The temperature at the bottom of RPV was not reported. Indicated Drywell pressure remains at atmospheric pressure. The indicated temperature at the feed water nozzle of the RPV in Unit 3 is stable at 118°C and at the bottom of the RPV is about 92°C. The validity of the RPV temperature measurement at the feed water nozzle is still under investigation.

Injection of water into the spent fuel pool in Unit 2 using the temporary pump was restarted on 1st April. The Common Spent Fuel Pool temperature is stable. TEPCO tested an ‘anti-scattering’ agent (2000 l) on 500 m2 area around the Common Spent Fuel Storage facility on 1st April. The purpose of spraying is to prevent radioactive particles from being dispersed from the plant by winds and rain.

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