Fukushima Daiichi update: Wednesday, June 22, 2011

Our updates on Fukushima Daiichi have slowed, as the number of, and seriousness of, developments on site also slows.

First we will cover conditions of the reactors. Water injection rates at all three units have been dropped again by TEPCO within the last 48 hours, so that the injection rates are now as follows:

No. 1 / 4.1 cubic meters per hour
No. 2 / 4.5 cubic meters per hour
No. 3 / 10.0 cubic meters per hour

This continued reduction is of course reflective of two things; first, the continuous slow lowering of heat output of the remaining fuel, and second the extreme desire of TEPCO to reduce to an absolute minimum the amount of water being deposited in the reactor building basements by the feed and bleed cooling that the reactors are receiving now. This reduction in flow rate has not seen an increase in monitored temperatures. Below, the reliable temperatures for all three units, given as feed inlet nozzle temperature first followed by lower vessel head temperature.

No. 1 / 114C; 99C
No. 2 / 108C; 108C
No. 3 / 144C; 128C

TEPCO continues to work vigorously to get these reactors off the feed and bleed cooling by installing what appears now to be an open loop design of cooling system, highly improvised, and on which we've reported before. This system would take a suction on water in the plant turbine building basements, purify and cool it, and then inject it to the reactors via the feed line (which at this point all three are using, and have been for some time.) To this end work continues to allow full access to the No. 2 and No. 3 reactor buildings to not only perform inspection, but to install new pressure vessel indications (water level, pressure) and prepare for further cooling system work.

This temporary gauge setup was installed at No. 1 plant, and its application seemed to confirm suspicion (in all quarters, frankly) that the pressure vessel was in better communication with the atmosphere than had previously been indicated by a failed instrument. The same type of instrument is now installed at No. 2 plant with remote TV signal being sent to the main operation center at the site, and we are awaiting the results after the setup is calibrated. I personally do not expect any surprising data to be revealed by this gauge setup - in other words, it will only serve to help confirm what we already suspect as at No. 1 plant.

The radiation survey on the first and second floors at No. 2 plant is complete, and readings around the floor are generally as expected -- as is the dose received by the persons entering. The highest reading on the first level is about 60 mSv/hr and on the second, near the instrument rack, about 79 mSv/hr. (That's about 6000 mr/Hr and about 7900 mr/hr for those of us here in the States.) However, readings ramp up as one progresses down the stairs toward the basement. It would appear that either very brief runs were made to the foot of the stairs at two corners, or else (more likely) that instruments were dangled down to the foot of the stairs and two readings were made. These readings came out at 388 mSv/hr and 430 mSv/hr, which for us is 38.8 R/hr and 43 R/hr.

As to the large and complicated Kurion/Areva water decontamination system: It must be remembered that this is not a factory-built system; it is a large assemblage of various components put together in ways that they SHOULD work to get the water cleaned up at the site. The major media outlets continue to report failures of this system, but they are all only temporary setbacks. For example, the latest official report of a system shutdown is involved with the overloading of a water pump, due to having too high a setting for recirculating flow. A valve adjustment was made to correct flow and bring pump load in line with its rating. This valve setting might well have been set roughly prior to operation, but fine tuning of any system is always needed and it's especially going to be so for such a system as TEPCO, Kurion and AREVA have set up here ... and the result is that continued full time, 'round the clock operation will only come with probably several more days of operating, finding weak points, and making fixes. It is the nature of the beast, one might say.

The work we've shown here on No. 4 reactor building to strengthen the support for the spent fuel pool continues. Some readers wondered about the structure being built, using steel support girders; these are now being filled in completely with concrete, which will create essentially a massive steel-reinforced concrete monolith holding up the spent fuel pool. The concrete is already going in at this time. Also at No. 4 plant, TEPCO is refilling the well at the top of the building adjacent to the reactor vessel area and the spent fuel pool, because loss of some of the water in this pool had exposed radioactive components normally covered by water, driving up the dose rate seriously on the refueling floor.

On-site installation of water storage tanks continues as mentioned before on this site, and which has been happening since June 8th. There is no hard figure at the moment of just how much capacity TEPCO has on site.

We will have more updates later as needed.

7:15 AM Eastern Wednesday June 22, 2011
ATOMIC POWER REVIEW