The concept of a half-life explains why LETHAL FOR THOUSANDS OF YEARS is a bit of an overselling of the situation.
The more radioactive a substance is, the shorter its half life. That is, the sooner it will become less radioactive. And vice versa: if a substance has a long half life, it will simply emit less energy per unit of time.
It's just inverse formulae. Nothing magical.
But people imagine high-powered radioactivity lasting for THOUSANDS OF YEARS. It just doesn't happen like that.
Jacques, I feel reluctant to disagree with you, because to search out the supporting references is a bit of a chore, but I had a good education in physics, I was a very good student, and I am confident that lethal for thousands of years is not overselling of the situation. If anything, thousands of years is underselling, as hundreds of thousands would be more accurate.
Let me help you with that. Jacques is correct in his description of activity. I just checked my radiation detection text book to make sure (that would be embarrassing wouldn't it!)
However, "lethal" is a bit of an ambiguous term when applied to the waste from the nuclear power generation. After cooling down, the fuel assemblies will most certainly be emitting ionizing radiation that will be detectable for hundreds of thousands of years, as you suggest. This does NOT mean it is "lethal" for this time period. UNLESS you open one of the assemblies and make an industrial waste smoothie. Most of the long lived isotopes contained in the assembly will be deadly as heavy metals. So there is still danger, but it is easily manageable, just like the waste from many other industrial processes (like making solar panels, or batteries for hybrids for instance).
Really? If that were true, you'd be able to answer him easily with facts and explanations that draw on those facts to provide an integrated understanding of reality.
I have a friend that just graduated from a nuclear engineering program. He is well-educated in physics.
The more radioactive a substance is, the shorter its half life. That is, the sooner it will become less radioactive. And vice versa: if a substance has a long half life, it will simply emit less energy per unit of time.
It's just inverse formulae. Nothing magical.
But people imagine high-powered radioactivity lasting for THOUSANDS OF YEARS. It just doesn't happen like that.