y***t
发帖数: 542 | 1 http://www.nuc.berkeley.edu/UCBAirSampling
3/21 (12:35pm): Rain water sampling results for precipitation from 3/19 10:
15am to 9:45pm is posted. Slight increase in activities are noted which may
be due to many reasons from actual increase from Japan to differing
atmospheric chemistry effects. Activity levels remain extremely low and
exposure to the public is insignificant.
3/20 (4:15pm): Rain water results show trace levels of radioactive iodine (
I131,I132), cesium (Cs134, Cs137), and tellurium (Te132). The amounts show
that the activity we are observing originated from any of the three
operating reactors that was shut down since I-131 and Te132 half-lives are
less than 10 days and the spent fuel from unit 4 had not operated for > 130
days. The calculated exposure to the public is so low that the consuming of
~500 liters of this water would only increase dose by the same amount
received by taking a cross-country airplane flight.
3/19 (8:37 pm) Initial analysis of first rain water sample has been
completed. Peer review of concentration amounts and radioactivity is in
progress. We expect to post results of multiple samples tomorrow. We
apologize for the delay.
3/19 (10:34am): Rain fall from 3/17-2pm to 3/18-12:15pm. Preliminary results
show trace amounts of radioactive iodine (I131, I132), cesium (Cs137, Cs134
), and tellurium (Te132) which are not naturally occurring elements and are
assumed to originate from the Fukushima nuclear site. In context, we also
see Be-7 (cosmogenically produced) and Pb-212 (radon daughter) which are
naturally occurring isotopes that also show up normally in rain water.
Preliminary analysis show levels remain well below that which would cause
health effects. We are currently awaiting better calibration of our detector
system to publish amounts.
3/18: Due to the rainfall overnight and throughout the day, we expect an
amount of "scrubbing" of the atmosphere as particles attach to rain drops.
We have collected many liters of rainwater and are currently shifting our
focus to sampling and testing the rainwater. Rainwater samples taken today
will be counted overnight with results to be posted tomorrow morning. In
addition, we are increasing our flow rate for air sampling and will not post
air sampling results until Sunday night. However, due to the expected
moderate levels of precipitation over the weekend we expect greater
sensitivity within the rainwater samples.
3/17 20:00 - 3/18 10:00: No detectable counts from radionuclides of interest
above background.
3/17 09:00 - 3/17 20:00: No detectable counts from radionuclides of interest
above background.
3/16 18:00 - 3/18 09:00: No detectable counts from radionuclides of interest
above background. | p****u
发帖数: 517 | 2 我也看了，这个检测主要是北加，对洛杉矶没有太多参考价值 | a*****s
发帖数: 838 | 3 不错，谢谢。周末可以放心去tahoe滑雪了。
may
【在 y***t 的大作中提到】
: http://www.nuc.berkeley.edu/UCBAirSampling
: 3/21 (12:35pm): Rain water sampling results for precipitation from 3/19 10:
: 15am to 9:45pm is posted. Slight increase in activities are noted which may
: be due to many reasons from actual increase from Japan to differing
: atmospheric chemistry effects. Activity levels remain extremely low and
: exposure to the public is insignificant.
: 3/20 (4:15pm): Rain water results show trace levels of radioactive iodine (
: I131,I132), cesium (Cs134, Cs137), and tellurium (Te132). The amounts show
: that the activity we are observing originated from any of the three
: operating reactors that was shut down since I-131 and Te132 half-lives are
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