apologies for a stupid question...
this may have been addressed previously, so i apologize if this is a repeat:
i see in the topsoil samples that i131 levels are decreasing, but are still present.
wouldn't this mean new plumes of radioactivity are continually arriving? i see other radionuclides decreasing in quantity in various foodstuffs, so clearly there's a slowing trend. but...why else would the iodine persist?
:(
. Arnie Gunderson of
.
Arnie Gunderson of Fairewinds, in a recent video update, discussed the continued radioactive Iodine releases from Fukushima.
If memory serves, he indicated that these iodine releases are (or may be) from Reactor 3, due to some remaining criticality excursion activity.
This is plausible, because Reactor 3 is fueled with MOX. MOX contains about 7% Plutonium. Plutonium is 'hotter' in both a thermal and radioactive sense. MOX is more active and harder to control. Stray criticality is thus plausible in Reactor 3.
I have not been tracking the iodine levels in Japan or the USA lately. But understand they are generally dropping in the USA.
The other concern is the SPENT FUEL pool in the Reactor 4 building. It will be 'big trouble' if that building collapses and spills a thousand tons of radioactive fuel rods onto the ground. By big trouble, Japan could become entirely uninhabitable. And the USA west coast could become a severely dangerous place.
I can nearly guarantee you
I can nearly guarantee you the I-131 (topsoil) will be a non-detect next time around. It has a half life of 8 days, and declined very rapidly, as one would expect.
I agree
The 8 day half life doesn't mean it will be completely gone in 16 days (two half lifes).
The BRAWM team has been refining their test analysis and have cut their
MDA from the 0.25-0.31 Bq/kg range, down to 0.10 Bq/kg in the most recent sample. The last sample would have been below the MDA of the first 4 out of 6 samples. But, because of their refinements, they are still able to detect the declining levels.
My comment was directed at the OP
I was agreeing with your comment. And adding that the short half life doesn't mean it goes away completely in two of those half lifes.
I didn't say it would be
I didn't say it would be gone, but I think it will be a non-detect. On 5-18 I-131 came in at .14 Bq/Kg (with a .10 MDA), 8 days later ir should be .07Bq/Kg (already below the 5-18 tests MDA) and on 6-3, 16 days since the 5-18 sample, I would expect the level to be .035 Bq/Kg.
So barring more I-131 having been released, or the team pushing the MDA way down, I think I-131 will be N/D next time.