I took “waste stream” to mean “the process after a device is no longer used.” Some waste is recycled, some is out in landfill, and more than should ends up in nature.
Most of the time, these types of things would be recycled. But obviously that doesn’t happen all the time. The rest of the time will be dominated by landfill, but that’s actually not that huge a problem. It’s not like the metals are going to grow legs and run around irradiating stuff any more than a Duracell. The last group is the environment proper, but keep in mind there’s already radioactive shit out and about in the world. You can find radioactive rocks literally just laying on the ground. It’s not actually that much of a danger unless a large amount of radioactive material (or a small amount of highly irradiated material which this is not) manages to find its way into a pile.
Honestly, I’d be more concerned about the conventional pollution aspect than the radiation.
Here’s the summary for the wikipedia article you mentioned in your comment:
A betavoltaic device (betavoltaic cell or betavoltaic battery) is a type of nuclear battery which generates electric current from beta particles (electrons) emitted from a radioactive source, using semiconductor junctions. A common source used is the hydrogen isotope tritium. Unlike most nuclear power sources which use nuclear radiation to generate heat which then is used to generate electricity, betavoltaic devices use a non-thermal conversion process, converting the electron-hole pairs produced by the ionization trail of beta particles traversing a semiconductor.Betavoltaic power sources (and the related technology of alphavoltaic power sources) are particularly well-suited to low-power electrical applications where long life of the energy source is needed, such as implantable medical devices or military and space applications.
Alright so, I added a sentence reduction functionality so the bot’s responses should be smaller now and also instead of using code markdown, I just made it so that the text appears bold. The spoiler markdown seems a bit unneeded here as the sentence reduction should already make the text small.
Not for space craft if what @MilderRichter says is right. To generate power from a peltier you need a temperature differential between the two sides. It is very hard to bleed off heat in space since it's a vacuum. That means a temperature differential is very difficult to achieve and it takes power to do that. Which would necessitate more of these, which means a bigger or additional heat removal system, which means you need more of these, which means a bigger or additional heat removal system, etc, etc, etc.