Since yesterday evening Tepco (or its subcontractors or sub-subcontractors) has been pumping highly radioactive water from the pipe and cable ducts under the turbine hall of unit 2 to the condenser storage tank. The presence of this water has been a major obstacle to reactivating cooling pumps or installing a new cooling system. The water has been in contact with damaged fuel rods and is loaded with fission products, with radiation levels exceeding 1000 mSv/hour.
A crack in a concrete wall near the cooling water intake building for unit 2 is being blocked with a steel sheet to stop radioactive water from leaking into the sea.
Yesterday a water sample was taken from the spent fuel pool of unit 4, which will be quantitatively analyzed for various radioactive isotopes to gain information about the state of the more than 1300 fuel rod assemblies in that pool. The spent fuel pool of unit 4 holds the biggest amount of long lived radioactive isotopes such as caesium 137 of all reactor cores and spent fuel pools at Fukushima 1. It has gaping holes in its walls and its roof was blown off in a hydrogen blast early in the nuclear disaster. When the cooling system failed due to a lack of external power after the March 11 quake, the fuel rods overheated and caught fire (it was that fire that prompted me and my family to head out of Japan the week after the quake…).
The last of five Putzmeister concrete pumps took off from Stuttgart/Germany for Japan in a Russian transport plane on Tuesday night. The remote controlled pumps have highly mobile arms 58 to 70 meters in length in 5 or 6 segments that are typically used for pouring concrete in dam or bridge construction, but can also be used for fire fighting. Between May and November 1986, 11 of the pump trucks were used to entomb the stricken unit 4 reactor in Chernobyl.