This week’s news from Japan

The latest information from IAEA.org on the Fukushima Daiichi situation.

IAEA Briefing on Fukushima Nuclear Accident (10 April 2011, 15:00 UTC)

On Sunday, 10 April 2011, the IAEA provided the following information on the current status of nuclear safety in Japan:

1. Current Situation

Earthquake of 7th April

External power has been restored at all sites affected by the 7th April earthquake. The 3 litres of water that were spilled at Onagawa NPP have been cleaned up.

Changes to Fukushima Daiichi Plant Status

Overall, the situation at the Fukushima Daiichi plant remains very serious but there are early signs of recovery in some functions such as electrical power and instrumentation.

In Units 1, 2 and 3, 60,000 tons of contaminated water need to be removed from the turbine buildings and trenches. This water will be transferred to the condensers of each unit and the Radioactive Waste Treatment facility. In addition, temporary storage tanks have been ordered to provide additional capacity for the water and will be located adjacent to the Radioactive Waste Treatment facility. In Unit 2 water transfer from the condenser to the condensate storage tank was completed on 9th April.

Nitrogen gas is being injected into the Unit 1 containment vessel to reduce the possibility of hydrogen combustion within the containment vessel. The pressure in this containment vessel is increasing due to the addition of nitrogen.

In Unit 1 fresh water is being continuously injected into the reactor pressure vessel through feed-water line at an indicated flow rate of 6 m3/h using a temporary electric pump with off-site power. In Units 2 and 3 fresh water is being continuously injected through the fire extinguisher lines at indicated rates of 7 m3/h and 7 m3/h respectively using temporary electric pumps with off-site power.

In Unit 1 the pressure in the RPV is increasing as indicated on both channels of instrumentation. NISA has indicated that some instruments in the reactor vessel may not be working properly. In Units 2 and 3 Reactor Pressure Vessel and Drywell pressures remain at atmospheric pressure.

RPV temperatures remain above cold shutdown conditions, typically less than 95°C. In Unit 1 temperature at the feed water nozzle of the RPV is 235°C and at the bottom of the RPV is 120°C. In Unit 2 the temperature at the feed water nozzle of the RPV is 145°C. The temperature at the bottom of the RPV was not reported. In Unit 3 the temperature at the feed water nozzle of the RPV is 97°C and at the bottom of the RPV is 109°C.

The concrete pump vehicle sprayed fresh water (90 T) to the spent fuel pool in Unit 4 on 9th April.

There has been no change in status in Units 4, 5 and 6 and the Common Spent Fuel Storage Facility.

You can read the full update here.

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