Monday, April 18, 2011

Estimate depositions from Fukushima (global)

These are the results of simulations performed by EURAD, they have date of April 20th 2011 (next Wednesday):

Dry deposition of cesium-137 (Bq/m²)

Wet deposition of cesium-137 (Bq/m²)

Notice that the scale is two orders of magnitude larger in the second image, creating a false notion of safety if one does not realize that the colors mean very different things.

We should understand that this accumulated deposition does not decrease (or only so slowly that is trivial), so areas that are now getting 1-10 Bq/m² (Los Angeles, for example) will be (everything else equal) in the 10-100 Bq/m² zone in New Year. An area in the 100-1000 Bq/m² range (Tokyo, for example) will be in New Year in the 1000-10,000 zone, etc. 

Containment of reactor 2 leaking: extreme radiation blocks work

The most severe latest news from the destroyed nuclear plant is that the containment vessel of reactor no. 2 is leaking and is therefore probably damaged (Xinhua). This is probably related to the spike in radiation that impedes workers from approaching this reactor (Seattle Pi).

The radiation levels are so extremely high however that they may hamper any solution: the current plan implies to take the fuel rods with cranes and transport them in special sealed containers somewhere else, a plan successfully implemented in Three Mile Island. However it is not possible to do it while radiation levels are so extreme (Asahi).

Radiation in reactors 1 and 3 also too high

Radiation around 50 mS/hour has been detected in these two reactors at ground level. This implies that, by normal Japanese safety standards, workers can only be two hours in a whole year, five hours by the new ultra-lax safety standards fixed by Tokyo to face the catastrophe, a single hour by US standards.

Many contractors are refusing the emergency standard of 250 mS/hour.

1000 mS cause radiation sickness.

Source: The Japan Times.

Update (Apr 19): Arnie Gunderssen as always being most informative and pedagogic on what is going on at Fukushima (reactor no. 2 looking very bad, radiation at spent fuel pool is Chernobyl-like):

Gunderssen's informative videos can normally be found at the Fairewinds Associated page at Vimeo.

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