Fukushima Report Delayed as TEPCO Gets New Chance to Explain

[FBaggins]

14. Nope... I merely claimed that active fission ended years ago

Where's your source, FBaggins?



More than four years of posting on this stuff and still don't get even the basics of how a reactor works? That's stunning.

What's the source? Basic inalterable laws of physics... that's the source.

When a reactor is active, the fission reaction creates more than just heat for boiling water. It creates lots of other elements ("fission products&quot , many of which are radioactive. Those elements give off heat as they decay (adding to the total heat) and many of their decay daughter products are also radioactive (giving off even more heat).

Once the reactor has been running for awhile, the active fission makes up only ~90% of the total heat that the reactor produces (IIRC). The other 10% is from the decay of other elements. Some of them have very long half-lives (and thus have low activity and put out little of that heat)... and some have much shorter half-lives (and thus have much higher activity levels and coincident heat production).

Once the reactor is turned off, fission stops almost instantaneously - but the reactor is still producing 10% of the amount of heat from when it was active. This drops off fairly quickly as those short-half-life elements disappear. Within the hour (about when backup power was cut off) it's down to just a couple percent of the initial heat. Then the decline slows.

Now... I'm sure that you remember most of that... but you're missing what it means. The largest bq-counts of the Fukushima release are never really counted, because they're "noble gases" that are lighter than air and have incredibly short half-lives. Nobody "counts" them because they couldn't impact anyone and were quickly gone. The largest bq release that people pay attention to was the radioiodine with its 8-day half-life (and most common health impact). It took a couple months for that to disappear entirely.

Those elements die off because they are produced by the fission and their levels rise in a reactor until the amount dying off (half every eight days) equals the amount being created in the active reaction. When the fission stops, they aren't produced any longer and start to disappear. But the point is that it's gone.

Here's the point to pay attention to. If you can't detect those elements... then there isn't any fission going on. You can't have fission without creating the fission products that go along with it. It isn't physically possible.

Radioiodine is incredibly easy to detect/identify and impossible to hide. None has been found for almost four years... and therefore there has been no active fission since the reactors shut down as the earthquake struck. Q.E.D.