Feasibility of a home built beta cell or similar nuclear battery?

[JuggleFive]

I've read about why it would be nearly impossible for an individual to construct a working home built nuclear reactor (of any variety), but I've never understood why a home built nuclear battery couldn't be constructed (think Henry Moseley's work). The size and power output would be impractical I'm sure, but it would make for an interesting project/demonstration. Any thoughts/links/information you can share? Has this been done before?

 

[etudiant]

Not sure about homebuilt, but there have been designs using tritium powered lights to drive solar cells.
Terrible efficiency, but very robust and durable.

 

[QuantumPion]

The problem lies is obtaining any significant quantity of an isotope useful for an RTG.

 

[JuggleFive]

I was thinking more along the lines of a direct charge device rather than an RTG. Readily available source materials are weak and you really wouldn't want the risk of working with stronger sources anyway however, multiple weak sources charging a capacitor bank to provide a periodic short burst of power (every hour/day/week?) might be possible? It probably hasn't been done for a reason, I just can't figure out why.

 

[QuantumPion]

I was thinking more along the lines of a direct charge device rather than an RTG. Readily available source materials are weak and you really wouldn't want the risk of working with stronger sources anyway however, multiple weak sources charging a capacitor bank to provide a periodic short burst of power (every hour/day/week?) might be possible? It probably hasn't been done for a reason, I just can't figure out why.

There are such devices called betavoltaics, however the energy produced by radioactive decay is pretty small. You couldn't power a home that way.

 

[mheslep]

Well, is it not the case that the problem is cost and safety, not power density? Otherwise RTGs would never find a use? For instance: (say) Na-22 (half life 2 yrs, 0.5 MeV beta) would deliver almost ~0.3 kW/mole for a ~year, or 13 kW from one kilogram, so that a few kilos would heat/power most homes.

 

[mheslep]

The problem lies is obtaining any significant quantity of an isotope useful for an RTG.

Yes, of course, disregard above.

 

[1ledzepplin1]

Americium from smoke detectors?

 

[QuantumPion]

Americium from smoke detectors?

The specific power of Americium is around 0.1 W/g. One smoke detector contains around 1 microgram of Am. To make a RTG to power your home, with a thermal efficiency of 10% and an output requirement of 5 kW, you would need 500 kg of Am or 500 billion smoke detectors. Or you could just buy Americium from the source, google says it costs $1500/g. That comes out to $750,000,000. I doubt the world production rate of Am is that much though.