Why is long-lived radioative waste dangerous?

[Nick R]

There seems to be a lot of political concern about long-lived radioactive byproducts of nuclear power stations, to the point where nuclear power has been regulated out of existence in the united states.

But the intensity of emissions from material with a long halflife should be very low. Why should a site where this waste is disposed of be dangerous for thousands of years then?

I would think that once the short lived byproducts are gone (a few years), the only health hazard from a waste site would be from the chemical properties of the waste.

Is my perception wrong and is it just that new construction on nuclear plants stopped because coal plants are simply more profitable?

 

[Drakkith]

Long lived waste can still be dangerous. The problem arises because waste storage methods are far more likely to break down and leak the longer the waste is in storage. How do you design a leak-free storage method that is resistant to aging and natural disasters such as earthquakes? We're talking thousands of years here. Keep in mind that the "least dangerous" materials have half-lives not in the thousands of years, but in the millions to billions. Even a material with a half life of a few thousand years can still be harmful if ingested, inhaled, etc. Plus, the decay chain can lead through multiple elements, each radioactive itself, which complicates the issue further.

 

[Vanadium 50]

It's not millions or billions.

Nuclear waste becomes about as radioactive as the original ore after ~5000 years. (And only twice as radioactive after ~400 years). The exact number depends on the exact nature of the waste. But that's the scale.

Don't think this is short - 5000 years ago is Stonehenge, not even the Pyramids.

 

[sophiecentaur]

There seems to be a lot of political concern about long-lived radioactive byproducts of nuclear power stations, to the point where nuclear power has been regulated out of existence in the united states.

But the intensity of emissions from material with a long halflife should be very low. Why should a site where this waste is disposed of be dangerous for thousands of years then?

I would think that once the short lived byproducts are gone (a few years), the only health hazard from a waste site would be from the chemical properties of the waste.

Is my perception wrong and is it just that new construction on nuclear plants stopped because coal plants are simply more profitable?

The danger may be more understandable if you consider that there is a great deal of Energy available in a small lump of radioactive waste. Even when the short life stuff has decayed to a low level and it's stopped actually glowing, there is still a significant amount of potential damage stored up in what's left. If bits start to leak out and get into the system, some of it (micrograms) can get into people's bodies and stay there. That means that they could be getting decades worth of exposure to the very low level radiation that is coming from their bones etc.. Cancer and damage to sex cells is a long term business and it's a good thing that the authorities were scared about it early enough to get some regulations in place before big business started to exploit nuclear energy more than they have done.
There are many other substances for which the dangers are also cumulative and for which there are tight regulations. Sometines it is hard to understand without the actual figures to help - and it's the figures and statistics that count. (Try telling that to a nicotine addict!)