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Friday, June 24, 2011

Fukushima Daiichi Update: Friday, June 24, 2011

FUKUSHIMA DAIICHI ACCIDENT RECOVERY UPDATES...

TEPCO continues to reduce rates of water injection. Here are the injection rates, and feed nozzle / lower head temperatures at most recent update.

No. 1: 3.6 m³/hr; 119C/103C
No. 2: 3.5 m³/hr: 109C/110C
No. 3: 9.1 m³/hr: 151C/122C

At last report TEPCO calculated the buildup of roughly 400 tons of water per day due to the feed and bleed cooling.

Work in No. 2 reactor building continues. Not only has the temporary RPV pressure gauge been installed but also the nitrogen purge line to the dry well is now in place. Below is a TEPCO press release photo showing the equipment rack where the temporary gauge is installed, and the tripod for the television camera that transmits a view of the gauge to the TEPCO headquarters on site.


Also at No. 2 plant... The T-Hawk remote helicopter had an emergency, forced landing on the top of No. 2 plant's reactor building. Below is a photo showing the helicopter sitting on the roof. The helicopter was being used to sample particulate matter at the opening in the side of No. 2 reactor building according to TEPCO.


In a similar vein, TEPCO has sampled the air and any emissions above No. 1 reactor building using a concrete pumper truck modified for the job; this operation on the 23rd is seen below in another TEPCO press photo.


TEPCO continues rapidly to develop its plan to erect the first-style (as we are calling it here) containment structure, sometimes referred to as the 'fabric enclosure,' around No. 1 building and a few more details are now available. The steel structure will be supporting large sheets of fabric, now announced as being a polyester fiber fabric coated with vinyl chloride resin. This membrane will keep in any radioactive (or other) dust and gas, to be handled by an internal air filtration system capable of handling 40,000 m³/hr of air. The sheeting will of course keep out rain, snow and wind to allow the start of work inside. Much later on, a much more solid type of structure will be built at each reactor building when the preparations for defueling begin. TEPCO expects this first fabric enclosure to be complete at No. 1 plant by the end of September.

Make sure to look at the Atomic Power Review YouTube Channel (link at right of APR page) for the videos showing this structure in animation/CGI produced and released by TEPCO for the media.

Further dampening any thoughts of spent fuel pool criticality ... or prompt criticality... is a sampling run done on the spent fuel pool water at No. 1 plant on June 22. Below are the isotopes measured, their half lives, and concentrations:

Cesium 134 / half life ~2 years / 12,000 Bq/cm³
Cesium 137 / half life 30 years / 14,000 Bq/cm³
Iodine 131 / half life ~8 days / 68 Bq/cm³

Note the tiny concentration of the short-lived I-131, and the high concentration of long-lived fission product isotopes. At the first take this seems quite out of proportion if spent fuel pool criticality had been achieved recently.

At last report TEPCO calculated that its contaminated (on shore) water treatment system had processed ~2,489 tons of water. Problems with the system in terms of pre-operation valve lineups (throttling valve positions) seem to have been fixed so that the cesium adsorption portion of the system will now operate as planned. Meanwhile, TEPCO is working on desalination components in view to an end of completing the recycling of cooling water for the cores.

These are the updates for now; I will be posting an article over the weekend covering some observations, and things we can expect, concerning the future recovery actions at the site.

9:55 PM Eastern Friday June 24, 2011
ATOMIC POWER REVIEW

2 comments:

  1. Thanks Will. Looking forward to that article on future recovery actions.

    Call me stupid, but... I don't suppose you could put a circle around the remote helicopter in that picture could you?

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  2. @joffan: The helicopter is the object at upper center, dark colored, against the white colored wall. It appears to be facing roughly away from the camera with the tail boom pointing roughly toward it. So far this is the only image TEPCO has released; I imagine others will be forthcoming if/when they recover the helicopter.

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