Japan is battling to avoid a wider nuclear catastrophe after fresh explosions today at the damaged Fukushima nuclear power plant may have damaged the suppression (pressure control) chamber in reactor no 2.
Green Action of Japan reports:
Status of Fukushima Daiichi Nuclear Power Station Unit 2
Updated 2011/03/15 08:09
NISA is reporting the status of the Fukushima Daiichi Nuclear Power Station Unit 2
At 6:10 am this morning, TEPCO reported that there was an explosive sound from Fukushima Daiichi Nuclear Power Station Unit 2. This explosion might have caused damage in the suppression chamber (pressure control chamber)(*).
(*)Suppression chamber (pressure control chamber):
A facility that lowers the pressure of the reactor pressure vessel in case steam is not properly delivered to the turbine (due to its cessation) by leading steam to and cooling the suppression chamber through a venting tube.
The Emergency Core Cooling System uses water in this chamber as well.
Report from the chief cabinet secretary (quoted by Japan Atomic Industrial Forum):
Fire broke at unit-4 nuclear power plant. Unit-4 was out of service at the time earthquake occurred. It is presumed that the fuels stored in the spent fuel pit were heated by itself and hydrogen was generated from these fuels and explosion occurred. It is also presumed that radioactive nuclides are released to the environment directly through the broken building. We are trying to put fire to make things stable.
11:53 (Japan time, one hour ahead of Malaysia time)
Wind is <0-10m/h NE in the east coast of Ibaragi (in the south of Fukushima). (Fukushima figures are not available because of the quake damage).
11:00 Fukushima Update
Cabinet Secretary Edano reports elevated radiation readings:
30milliSv/h (yes, 30,000 microSv per hour) near Unit-2 and 100milliSv/h (100,000 uSv) near Unit-4 of Fukushima-I (=Daiichi). – Press conference at PM’s Office, 11:15am Tokyo time (+900)
10:15 Spent Fuel—Fukushima Update
NHK has now reported that the spent fuel pool at Fukushima Daiichi (Unit 3) does not have a roof over it since yesterday’s explosion.
There is no electric source, and there is a possibility that it has lost cooling ability. There is steam around the roof top. The connection between this and the other is unknown.