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Wednesday, April 20, 2011

Japan : Fukushima Nuclear Accident Update Log

The latest update from IAEA, excerpt :

" IAEA Briefing on Fukushima Nuclear Accident (19 April 2011, 18.00 UTC)

1. Current Situation

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

On 17th April, the Ministry of Economy, Trade and Industry (METI) announced that TEPCO had issued a "Roadmap towards Restoration from the Accident at the Fukushima Daiichi Nuclear Power Station". The roadmap outlines 63 measures to be taken in two steps over a period of six to nine months.

Changes to Fukushima Daiichi Plant Status

The IAEA receives information from a variety of official Japanese sources through the nation's national competent authority, the Nuclear and Industrial Safety Agency. Additional detail is provided in the IEC status summary with information received by 07:00 UTC on 19th April 2011.

The IAEA receives information from a variety of official Japanese sources through the nation's national competent authority, the Nuclear and Industrial Safety Agency. Additional detail is provided in the IEC status summary with information received by 07:00 UTC on 19th April 2011.

TEPCO has provided a plan to NISA for the transfer of highly contaminated water from the basement floor of the turbine building of Unit 2 to the Main Building of the Radioactive Waste Treatment Facilities in order to reduce the risk of this stagnant waste water being discharged to the environment.

On 17th and 18th April, an unmanned robot was used to conduct inspections of the Reactor Buildings in Units 1, 2 and 3.

As of 18th April, white smoke was still observed coming from Units 2, 3 and 4.

In Unit 1 , fresh water is being continuously injected into the RPV through the 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 an indicated rate of 7 m3/h using temporary electric pumps with off-site power.

RPV temperatures remain above cold shutdown conditions in all Units. In Unit 1 the temperature at the feed water nozzle of the RPV is 170°C and at the bottom of the RPV is 115°C. In Unit 2, the temperature at the feed water nozzle of the RPV is 142°C. In Unit 3 the temperature at the feed water nozzle of the RPV is 100°C and at the bottom of the RPV is 114°C.

In Unit 1 Nitrogen gas is being injected into the containment vessel to reduce the possibility of hydrogen combustion within the containment vessel. The pressure in this containment vessel has stabilised. The pressure in the RPV is increasing. In Units 2 and 3 Reactor Pressure Vessel and Drywell pressures remain at atmospheric pressure.

On 18th April the concrete pump truck sprayed water into the Unit 3 spent fuel pool. On 17th April, approximately 140 tonnes of fresh water was pumped into the Unit 4 spent fuel pool.

There has been no change in the status in Units 5 and 6 or in Common Spent Fuel Storage Facility. On 17th and 18th April, anti-scattering agent was sprayed over an additional 3100 m2 area near the Centralized Waste Treatment Facility."

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