Norwegian Institute for Air Research: Potential Fallout Forecast

This report from the NILU was discussed earlier. Here is a reply from Berkeley team member bandstra:

A few disclaimers
Submitted by bandstra on Mon, 2011-04-04 23:10.
The tools they are using appear to be very sophisticated and realistic codes for air transport modeling. This is not my area of expertise, but I am getting this from reading the technical parts of their website.

I think there are a few things to keep in mind when interpreting this information:

•In Berkeley we are measuring the "Surface Concentration" of the radioisotopes -- their density in air near the ground. The "Total Column" data gives the total amount of the radionuclide per area, summed from the surface to the top of the atmosphere -- that is, it hasn't settled yet. So I would ignore the "total column" information since the "surface concentration" is more like what we are measuring.
•The color code uses a logarithmic scale, not a linear one, so be careful when interpreting the amounts.
•They are plotting the surface concentration in units of Bq/m^3. Our data is in Bq/L. To convert our measurements from Bq/L to Bq/m^3, you need to multiply by 1000. So for example, we are measuring ~2E-6 Bq/L = 2E-3 Bq/m^3 of I-131 and ~2E-7 Bq/L = 2E-4 Bq/m^3 of Cs-137. We can measure down to ~1E-8 Bq/L = 1E-5 Bq/m^3. The bottom of their scales seem to go to 0.1 or 1 Bq/m^3. So we would *definitely* be able to measure anything that is plotted with a color on their maps if it comes here.
•Last, I found the following disclaimer on the page you linked. I have put some parts in bold:

"These products are highly uncertain based on limited information for the source terms. Please use with caution and understand that the values are likely to change once we obtain more information on the overall nature of the accident. The products should be considered informational and only indicate 'worst case scenario' releases. From what we've learned recently, it seems releases of this magnitude have not yet occurred. Furthermore, these modeling products are based on global meteorological data, which are too coarse to provide reliable details of the transport of the plume across Japan.

"Currently we are using a daily releases distributed evenly of 0.1E18 Bq I-131, 0.1 E17 Cs-137, and 0.1 E19 Xe-133 per day."

So keep in mind that they are doing an absolute worst-case of a HUGE amount of constant radiation release. There is no evidence that there is a release of that size, and there is no evidence that it is constant. Also, I noticed that they are not taking into account the half-life of the isotopes in their daily release rates, so that is another place where they are being conservative. If nuclear fission stopped when the reactors were scrammed on 3/11, then the amounts of I-131 and Xe-133 inside the reactors would have begun decaying away. It would be likely that the release rates of I-131 and Xe-133 would be affected -- i.e., less and less would be released. However, as they note, there is not much yet known about the "source term" -- how much was released at what time(s).

I hope this helps.

What I was wondering is this: if it is possible that the xenon will arrive in California at dosages like in Japan, why should the other particles like iodine, cesium, stronitum not have arrived at the same concentrations like in Japan? Why should xenon be different?
That is my fear, deep in my heart that we are being lied to by the EPA about the true past levels of iodine, cesium and so forth.
It appears that there is NO dilution factor when looking at the xenon cloud prediction.