Fukushima apocalypse: Years of ‘duct tape fixes’ could result in ‘millions of deaths’

[PamW]

37. Think about it..

zeemike,

Think about it. Why do you have to cool spent fuel? It's because of "decay heat" which is due to the radioactivity of the fuel. The more radioactive the fuel is; the more heat produced.

However, you must also know that radioactivity exponentially decays. So as time goes on; the exponential decay of the radioactivity, also means exponential decay of the decay heat.

A nuclear reactor is refueled about once a year to once every 18 months. Let's say we refuel every year and that we have just completed the refueling cycle for a 40 year old reactor.

So in the spent fuel pool, we have newly discharged spent fuel which is as radioactive as spent fuel gets.

We also have some that is 1 year old, with less radioactivity. We also have 2 year old fuel, 3 year old fuel....40 year old fuel.

The "younger" batches of spent fuel still haven't radioactively cooled down; so you have to keep the pumps going to cool them.

However, that decades old fuel has cooled down. That's the type of fuel that no longer needs the forced circulation, and could be put into dry cask storage if the utility has those facilities.

So when you compute how much radioactivity could be released; it is ERRONEOUS to include the radioactivity of the decades old fuel. That fuel doesn't produce much decay heat and is not going to melt even if you don't keep it submerged in circulating water. The heating rate is low enough that forced cooling is no longer necessary; so one can put those into dry casks that don't have active cooling. That fuel isn't going to melt.

You DO need the forced water cooling for the "young" spent fuel. That fuel still has the potential for melting.

But when you say how much radioactivity could possibly be released, you should ONLY count the radioactivity in the rather "young" spent fuel that has a possibility of melting.

You should NOT include the radioactivity in the decades old fuel that can't melt due to the lowered decay heat.

The only reason for using the 40 year total inventory of radioactivity including the decades old fuel that won't melt; is so you get an artificially high number so as to needlessly scare as many people as possible, which is what the anti-nuke propagandists do.

If you are a scientist; you restrict the possible radioactive release to only the "young" spent fuel that actually still needs active cooling.

The good thing about science is that it is true, whether or not you believe in it.
--Neil deGrasse Tyson

PamW