APR: your source for nuclear news and analysis since April 16, 2010

Thursday, May 5, 2011

Fukushima Daiichi updates... May 5th

There are several updates this evening...

-TEPCO has responded to NISA's request regarding the safety of flooding the dry well of No. 1 plant. According to the report (I've read it) there will be no hazards to the dry well or building structurally. NHK has reported that this reactor plant's dry well and reactor pressure vessel volume will require about 7400 tons of water to be added to cover the fuel. TEPCO assures that the building will hold against the originally designed seismic parameters even with the added water mass.

-The air filtration equipment has been installed at No. 1 unit preparatory to making the environment habitable for long enough periods to perform necessary work. This will take about three days' worth of operation to reduce the airborne inside No. 1 reactor building to levels NISA is comfortable with for sustained entry.

-Water injection rate at No. 3 plant has been increased slightly to mitigate a slow temperature rise; this is the non-specific flow rate increase reported here earlier in the week.

-TEPCO has stated that the decay heat removal required for No. 1 plant .. to be dissipated by the partly "rigged," partly installed system .. amounts to about a 1500 kilowatt rating and will require about 100 tons of water per hour.

9:30 PM Eastern Thursday 5/5


  1. Unit 3 core temperature has risen from 100 to 240 C within a week. Containment max. is 280 C.

  2. @ashen: As of 5:50 AM Saturday, the data I am seeing are that feed nozzle temperature of No. 3 plant is 180.2C (data as of 0700 May 7) from one source, and temperature trends of a fairly steady roughly 110C + over about a week or more to about 140C + on the 4th of May.