TEPCO finished the fortification job for the Spent Fuel Pool in Reactor 4 on July 30.
Now, according to NHK News Japanese (7/31/2011), TEPCO is going to conduct a test run of the heat exchanger that it also finished installing for the SFP. The company hopes to lower the temperature of the SFP from the current 87 degrees Celsius to about 30, just like in Reactors 2 and 3.
The carbon-based workers had to carry everything up the stairs in full radiation protection suits and full face masks and do the work in high radiation. It'd better work, and it'd better be a step forward.
Next, a step backward:
One pump stopped at Kurion's unit of the contaminated water treatment system, and TEPCO decided to stop the transfer of the contaminated water from Reactors 2 and 3, as the Central Waste Processing Facility (where the water is stored before treatment) is nearing the capacity (20 centimeters from the limit), according also to NHK News Japanese (7/29/2011).
Hitachi's desalination unit is stopped due to a water leak, although the water treatment to remove radioactive materials continues uninterrupted.
And then, an enigma:
TEPCO conducted the air sampling from inside the Containment Vessel in Reactor 1, expecting the very high density of radioactive materials, but the result, after workers got max 5 millisieverts for the work on July 29, shows the air inside the Containment Vessel is just as clean/dirty as the air outside the Containment Vessel. TEPCO was expecting the air inside the CV to be 1,000 times as contaminated as the air inside the reactor building (but outside the CV).
So, what are the possible reasons as to why the air inside the CV is no different than the air outside?
TEPCO's Matsumoto thinks it may be because cesium tends to dissolve into water.
Or it could be that all that was inside the CV blew out and was gone when the reactor building blew up.
It could also be because the corium has long gone from the Containment Vessel and deep into the concrete (I hope) that it doesn't affect the air very much any more.
Remember TEPCO hasn't done (or released) the testing of the water in the basement of Reactor 1 reactor building, and that water was gushing in steam which measured 1,000 millisieverts/hour. Something very hot (temperature and radiation) is under that water.
TEPCO has been sending in workers to Reactor 1 regardless, to install the heat exchanger for the Spent Fuel Pool.
That, by the way, is another thing that hardly any information has been released by TEPCO: the SFP of Reactor 1. What's the radiation level of the water in the pool? What happened after the explosion? What's the temperature of the water? What happened to the spent fuels?