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Saturday, June 11, 2011

Fukushima Daiichi update: Saturday, June 11, 2011

It has been three months since the Great East Japan Earthquake today. Also, then, as a result three months since the initiation of the Fukushima Daiichi Accident by the tsunami which resulted from the earthquake and which inundated the site. The tsunami then caused what in many quarters is recognized now as the classic long-term SBO event but extended to a point not previously imagined without either AC or DC power on site, and with further equipment derangement than generally imagined due to the tsunami waters which overran what had been assumed to be worst-case-preventive defenses. Accident recovery has been hampered by the hydrogen explosions in the reactor buildings, which from the explosion in No. 1 building led to many further site complications due to debris from one plant interfering with actions at other plants, thus causing a complicated interrelation of cause and effect sequence and decision making not perceived as probable in design basis accident analysis. While many of the events on site have actually been exactly predicted -- even down to roughly the hour or two hour event times -- by previous accident analysis studies (mostly under the auspices of Oak Ridge National Laboratory) many of the complicating factors were not. Just as TMI-2 led to a re-evaluation of how many seemingly unrelated existing flaws both in personnel and equipment can lead to an accident that essentially fills a DBA scenario without being a classic DBA event, so now does Fukushima Daiichi cause the nuclear industry to widen its scope particularly and thoroughly on multi-reactor nuclear generating sites where the reactor plants are closely spaced, or worse, immediately adjacent. This is not by any means the sole area to be studied, but it fairly jumps out at the investigator at even the most cursory examination. With that, here are the most recent details from Fukushima Daiichi.

TEPCO is now testing its large water purification facility, assembled over the last week or so. TEPCO still intends to have this equipment functioning within the next week.

Water injection rates to the reactor plants remain unchanged. Temperatures at No. 1 and No. 2 plants are stable, but No. 3 continues to drift upward, with bottom vessel head temp at last report being 189.2C (372.6 F).

Today, in the effort to gain working access to all reactor buildings for restoration of pressure and water level detection, and restoration of spent fuel pool systems, TEPCO finally opened up the double air lock doors at No. 2 plant and began working on filtering the air. In No. 3 plant, gamma camera surveys were conducted to map out the areas of high radiation in preparation for the aforementioned events and for the preparations for nitrogen injection to the primary containment. Areas of up to 10R/hr were found in No. 3 plant's reactor building. Nitrogen injection to No. 1 plant still continues, only rarely interrupted due to outage or nitrogen generator problems so that at the moment TEPCO estimates that over 43,000 cubic meters of nitrogen gas have been injected to the dry well for the purpose of inertion (against hydrogen gas combustion / explosion.)

Personnel have entered No. 4 plant as noted earlier to support the spent fuel pool, and some new TEPCO press photos are now available. These were taken on June 9th and 10th. First, the fourth floor view:

Next, water treatment equipment in No. 4 reactor building.

The damage seen above is considered by TEPCO to be serious enough to hinder its attempts to restore the original spent fuel pool systems for the purpose of cooling the spent fuel pool. Not only is there debris everywhere, but there is also piping damage that TEPCO apparently had expected not to find.

TEPCO continues to bring in water storage capacity as rapidly as possible. The large tanks mentioned on this site a short while back are now arriving on site and are being mounted and connected. First of our two TEPCO press photo displays is one of the tanks during the night-time shipping routine, chosen to avoid obstruction of roads and thus daytime traffic.

Below, the installation of the tanks at the Fukushima Daiichi site.

These are the most important confirmed details at the moment. More to come.

10:25 PM Eastern Saturday 6/11


  1. Looking at the pictures from reactor 4, it seems that the explosion originated from within the wiring cabinets, because they are blown open, not blown in.
    That suggests the hydrogen leak path was up through the wiring conduits.
    Is there any useful information on where these cable conduits start? It might provide some better understanding of the origins of this accident.

  2. I venture some the conclusions will entail more reinforcement and independent systems between adjacent multiple units which I'm for more of since it'd significantly cut the problems with site selection and fretful unenlightened citizenry. I wonder are there any truly underground plants anywhere? I'd think old lava or salt caverns would make perfect multi-unit nuclear plant sites!

    Have there been any calculations of how long if possible a slow refrigerated cool-down of the vessels via recirculated vessel coolerant would take? Seeing the effort of bringing in all these tanks and barges I picture that pumping that reactor vessel out-take of hot water through a series of refrigerated trucks and back in might've been a quicker and less cumbersome deal than hauling in all these containers which could be used instead to drain the lower portions of the plant. I'm sure more than few Japanese citizens had similar wonders. Another thing I wish the parties involved could do is translating bio-radiological terms into "body damage equivalents" terms (granted maybe a little simplistic) that the lay person could relate to; i.e. is 10R/hr like being tan-broiled on the beach for 20 hours or a second or third degree burn from a fire or losing a finger or arm in terms of body damage or what. Too many in media casually sling the rad terms about without explanation as though letting fear or ignorance exaggerate the peril for them.

    I am puzzled by the lack of remote control robots (unless they're nor shared) among these Japanese plants if not for anything but normal nuclear materials handling, bit they almost came out seeming clueless about such here. I mean, supposedly even Indian Point and Millstone near here a pair of "police bomb disposal" type thingies ready to roll to scrub up some turbine leaks. They can't be all THAT expensive! I'd be interesting to know how fast this work would be if the plant WASN'T radioactive, but still with the same heat/plumbing issues.

    It is interesting that, despite what these plants endured above and beyond the call of duty -- not just one but four simultaneously -- and Doomsday or even mini-mass deaths hasn't occurred (quake victims overlooked), how the media is now skunking around looking for any mutations or freak births to come to please pit SOME blame on evil nuclear energy. Some anti-nuke sites are so disturbed/disappointed by the less than cataclysmic events that they've whipped out new worst case scenarios to ban nukes, like chances for point-blank meteor strikes, a love-lost nuke worker sabotaging the plant to take everyone with him to hijacked NATO bombers flown into a plant. I kid you not -- I read them of the links here! I'm glad to see more cross-pollination of readers and cross-mentions among nuclear blogs nowadays.

    James Greenidge

  3. Good suggestion, netudiant, and worth exploring, although also it's possible that the wiring cabinets were only the ignition point after the building had filled with an explosive mix, rather than the path of hydrogen ingress.

    Certainly those photos solidify the evidence of an explosion deep within building 4.

  4. > blown open, not blown in

    I'd think the hydrogen would have been mixed well by diffusion as it accumulated throughout the area -- the cabinet doors wouldn't have done anything to keep the hydrogen either out of the cabinets or inside them.

    Here's a different hydrogen explosion that also seems to have popped open some cabinets or computer enclosures or something similar: