29 March Log Entry "Expected Decline"?
Aren't we looking at Fukushima of about a week ago? I think they were venting reactors directly to the atmosphere until about 48 hours ago. Won't we see a steady state for another 4-5 days?
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Aren't we looking at Fukushima of about a week ago? I think they were venting reactors directly to the atmosphere until about 48 hours ago. Won't we see a steady state for another 4-5 days?
You are absolutely right
You are absolutely right that we are seeing radiation that was released approximately one week previous, so we shouldn't expect to see a decrease due to air transportation alone until about a week after all releases have stopped. There is a lot of uncertainty as to when and how much has been released over the last couple of weeks, and whether releases will continue.
What we meant is that since all of the fission product isotopes stopped being produced when the reactors were scrammed on March 11, we should expect to see a gradual decrease due to radioactive decay alone (except for Cs-134 and Cs-137, which have half-lives of 2 and 30 years, respectively. So even if the radiation release were done at a constant rate since March 11, we wouldn't see a steady state over here but a steady decline (neglecting the complex way the particles are transported through air, of course). This decline should eventually happen regardless of how they are transported.
I thought in a meltdown as
I thought in a meltdown as the Japanese have confirmed recently, new fission takes place? Shouldn't that increase the iodine and cesium in the next days?
No fission takes place in
No fission takes place in the event of a meltdown. All that happens is that the fuel is too hot and physically melts.
So have we (on average) peaked then?
1) Isn't the worst case outcome a meltdown? (If not, what is?)
2) So even in the worst case, we would still expect to detect an (average) decline in radionuclides over time (and therefore we have already peaked)?
That would be a relief to know!
Thanks so much.
Worst case scenario is an
Worst case scenario is an uncontrolled fission event (super critical), where enough energy is created to produce an explosion that breaches primary containment. This is the Chernobyl scenario and this is most likely not in the cards.
We may not have peaked as there has been significant releases in the past week in Japan of radio-iodine. If we don't get any rain here, we may not observe these peaks as we did last week. Weather is a wildcard parameter.
NISA (Japanese Nuclear
NISA (Japanese Nuclear Safety Organization) released a document on 26 March that purports to be a radionuclide assay of the water found in the turbine room of reactor one:
http://www.nisa.meti.go.jp/english/files/en20110325-6.pdf
This shows a strong signal for chlorine-38. I am told that the short half-life of Cl-38 implies that there is still fission taking place. What is the meaning of that isotope, does the report seem plausible, and does that have any consequences for your testing?
Thanks for your response!
Thanks for your response! I've seen more than one poster mentioning that we are already at Chernobyl levels. I am not sure what they mean by that.
I have been following this message board from early on and it has been really interesting and educational, but more recently it seems that there are a number of posts that don't seem credible, perhaps people who find it funny to post alarming messages? I am hoping that this message board is not going to be degenerated by pranksters.
Chernobyl used a carbon
Chernobyl used a carbon based fuel. This allowed greater dispersing through fire and smoke. Japan is clearly the second worst nuclear disaster in history. Remember this continues and the amount of material released into the environment is rising. Let's try not to predict the future.