Rain sample update 1/13/2012

Submitted by bandstra on Fri, 2012-01-13 13:47

1/13/2012 (12:50pm): We are back from winter break now, and we have posted the results of a rainwater sample that was collected in November. The results have been posted in the data table on the Rainwater page. As with all our rain samples since April 20, no fission product isotopes were seen above MDA.

Mark [BRAWM Team Member]

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Mark please explain te132 mda dramatic increase

Submitted by Anonymous on Sat, 2012-01-14 11:14.

"Submitted by dchivers on Thu, 2011-03-24 06:31.
We do see Te-132 and the decay daughter of I-132 along with I-131, Cs-134, and Cs-137 in trace amounts. Just because we see Te-132, does not necessarily mean a core meltdown, but it does indicate a significant release of fission products from the fuel. Te-132 has a half life of about 3 days and therefore we know this is from one of the three operating reactors that were shutdown at the earthquake as opposed to the spent fuel pools which had been shutdown for greater than 100 days. When a reactor shuts down, the production of these nuclides cease and this kind of starts a clock where after a certain amount of time, certain nuclides decay away. Te-132 is one of these and so it gives us some indication of where the release came from. No data from our measurements point to a meltdown, however, I think the accepted assumption is that all three units at Fukushima have some sort of core damage. The extent of this damage is still unknown.
http://www.nuc.berkeley.edu/node/2696
The levels are now down at or below their minimum detectable amount."

I noticed in this most recent result your mda for tellurium 132 has dramatically increased from a .0042 to a 1.82 . Care to help me understand .thank you .tdm

Time between collection and measurement

Submitted by bandstra on Sat, 2012-01-14 11:35.

Hi Tdm,

The major difference between the previous samples' MDAs and the most recent sample is the time between the collection and measurement. We always back-correct our measured activities (i.e., the activity when the sample is in front of the detector) to the time of collection (i.e., when the rain fell). The purpose of this is to account for the radioactive decay of the isotope.

In the case of Te-132, it is the isotope we tested for with the shortest half-life (3.2 days). Since we collected the rain sample during our down period, we were not able to test it for a number of weeks, during which several half-lives of Te-132 elapsed. Hence the MDA is higher than previous samples, which were tested within days of being collected.

Mark [BRAWM Team Member]

thank you, brawm!

Submitted by Anonymous on Sat, 2012-01-14 09:18.

wonderful to see continued testing, even if more intermittent! i have two very young sons--one 4 months old--and i still wonder about my breastmilk... :/

at any rate, thank you so much. i look forward to a little more milk and food chain testing, when the opportunity arises!

Second verse, same as the

Submitted by Anonymous on Fri, 2012-01-13 23:30.

Second verse, same as the first... Nothing to see here everyone! Everything's fine! Don't run! We are your friends!

And the band played on!

Thanks for the new update

Submitted by Anonymous on Fri, 2012-01-13 16:39.

Was curious if any of the sizable oceanic releases could be transported/deposited via evaporation and subsequent rainfall...glad to know that you're still monitoring.