The IAEA has posted another report on itsFukushima Nuclear Accident Update Log. Excerpt:
On Thursday, 31 March 2011, the IAEA provided the following information on the current status of nuclear safety in Japan.
1.Current Situation
Overall at the Fukushima Daiichi plant, the situation remains very serious.
The Unit 1 condenser is full. Pumping water from the Unit-1 turbine building basement to the Unit-1 condenser has been stopped as of 22:30 UTC on 28 March. For Units 2 and 3, in order to prepare for removal of the water from the turbine building basement, pumping of water from the condenser to the suppression pool water surge tank started at 07:45 UTC 29 March and 08:40 UTC March 28 respectively.
For Unit 1 fresh water has been continuously injected into the Reactor Pressure Vessel (RPV) through the feed-water line at an indicated flow rate of 8 m3/h using a temporary electric pump with diesel backup.
In Unit 2 fresh water is injected continuously through the fire extinguisher line at an indicated rate of 8 m3/h using a temporary electric pump with diesel backup.
In Unit 3 fresh water is being injected continuously at about 7 m3/h into the reactor core through the fire extinguisher line using a temporary electric pump with diesel backup.
The indicated temperature at the feed water nozzle of the RPV on Unit 1 has decreased from 281 °C to 251 °C and at the bottom of RPV decreased from 134 °C to 128 °C. There appears to be a corresponding decrease in RPV pressure with a slight decrease in Drywell pressure.
The indicated temperature at the feed water nozzle of the RPV of Unit 2 has increased from 177 °C to 181 °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 about 89 °C and at the bottom of RPV is about 114 °C. The validity of the RPV temperature measurement at the feed water nozzle is still under investigation.
No further information is available regarding the plan to commence the pumping of water into the Unit 1 Spent Fuel Pool by concrete pumping truck from 29 March.
On Unit 2 the temporary electric pump supplying water to the spent fuel pool experienced a malfunction. Spent fuel pool water supply was changed to a fire truck pump but a crack was discovered in a hose on 30 March 04:10 UTC. Pumping water to the spent fuel pool was therefore stopped. Pumping was subsequently restored and water was fed into spent fuel pool in Unit 2 from 10:05 UTC on March 30. Water injection into the spent fuel pool in Unit 4 by concrete pump was completed at 09:33 UTC on March 30.
Units 5 and 6 remain in cold shutdown.
