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

Saturday, July 2, 2011

Fukushima Daiichi Update: Saturday July 2, 2011

There is little significant news to report from the site over the last several days; here are the highlights.

-Further inspection of the spent fuel pools, including high quality photos of the spent fuel pool at No. 4 plant, is revealing less damage than previously assumed. Japanese media are reporting that the spent fuel pools at No. 2 and at No. 3 plants are cooled to or below 40C and stable, with their original spent fuel pool cooling systems operating in nearly normal fashion. No. 1 and No. 4 plants are more problematic in terms of restoration of the systems, with No. 4 being worse by far due to system damage. However, the actual condition of the spent fuel itself in No. 4 plant's spent fuel pool is not nearly as bad as might have been suspected... or as was reported in some outlets. Below, high-res TEPCO press photo of the spent fuel pool surface taken on the refueling floor level.
Click to enlarge; courtesy TEPCO.

-TEPCO is cleaning up some debris in No. 3 reactor building using a three-unit system comprising a large industrial vacuum, a filtering system, and a robot. Below is a TEPCO press photo of the robot in use for this task.



-TEPCO has begun transfer of low-level contaminated water to the mega-float, docked at the shallow draft pier at the Fukushima Daiichi site. The roughly 10,000 ton capacity of this unit greatly adds to TEPCO's water storage inventory. At last estimate about 120,000 tons of contaminated water were on-site (this includes all contaminated water in all buildings, tunnels and tanks.)

-Nitrogen injection continues at No. 1 and No. 2 plants' dry wells. Note: While this is not essentially breaking news, it is important to monitor the threat of radiolytic hydrogen at the three damaged reactor plants; we will report any developments in this area here as soon as they're released.

-Water injection to the reactor cores (plants No. 1, 2, 3) continues as much as possible from the decontamination system, although at last report TEPCO had briefly switched back to direct injecting fresh water to allow installation of a buffer tank in the system in line before the reactor injection pumps. Feed rates and temperatures at last report are as follows:

No. 1 plant: 3.6 m³/hr, feed nozzle 118C, lower head 102C
No. 2 plant: 3.5 m³/hr, feed nozzle 113C, lower head 128C
No. 3 plant: 9.0 m³/hr, feed nozzle 154C, lower head 125C

-A large embankment has been completed on the water side of the Fukushima Daiichi station to prevent further effects of water from offshore for any reason. The two pictures below are courtesy TEPCO; the first is on the water side of the rad waste building, looking south. This is the southern tip of the Fukushima Daiichi station. Note the many large iron castings used to reinforce the retaining wall.
This is a very large picture; click to enlarge.

Below is another photo taken from a position further south, and higher up on the tiers of defense. Notable in this picture are the different types of material used in different layers - and also notable in the distance is the enormous crane being set up to construct the reactor building enclosure at No. 1 plant.


7:12 AM Eastern Saturday July 2, 2011
ATOMIC POWER REVIEW

No comments:

Post a Comment