Re: Diamonds turn nuclear waste into nuclear batteries
Posted: Tue Sep 01, 2020 10:36 am
Nickle has a density of 10 grams per cm3. Carbon 14 is 1 grams per cm3. So we get somewhere between 1 uW/g and 5uW/g power density.
Pretty awful...
Now, I have done some digging on my own and what I found to be a near perfect beta emitter in terms of half life (~29 years) and power density is Strontium 90.
Now that (by itself) emits about 1 kW of energy per gram in the form of beta particles. Or rather it decays into an Yttrium 90, which in turn beta decays into Zirconium 90 within 64 hours. The latter is where the meat is with electrons of ~1.14 MeV of energy released in the beta decay. The electron released by the Sr90 by itself is only about 0.27 MeV. But combined they have quite an "oomph". And this happens at a rate of 5.21 TBq/g.
Problem is of course that a betavoltaic device would not just be made of Sr90...
So anyway, I did the math and wondered. Why has no one done that? It sounds near perfect. And low an behold... someone did!
https://www.nature.com/articles/srep381 ... 8GsSW7I-CI
"A collection of such devices that generates 100 W would weigh less than 5 kg".
So we get 20 Watts/kg. Not great, but not bad at all. One could make a car battery from that. Of course with Sr90 come other problems... It is extremely dangerous when ingested since it gets integrated into bone. That in turn will likely cause bone cancer. So for consumer applications, it is no darn good.
Plus it will need some shielding too...
Also noteworthy is that Sr90 works better in an RTG where I calculated a power density of ~33 watts/kg (assuming the highest efficiency of 7%). Of course for space applications you will need cooling too then if you want your RTG to work...
Oh well, those nuclear batteries are still a dream that just does not want to come true, I am afraid.
Pretty awful...
Now, I have done some digging on my own and what I found to be a near perfect beta emitter in terms of half life (~29 years) and power density is Strontium 90.
Now that (by itself) emits about 1 kW of energy per gram in the form of beta particles. Or rather it decays into an Yttrium 90, which in turn beta decays into Zirconium 90 within 64 hours. The latter is where the meat is with electrons of ~1.14 MeV of energy released in the beta decay. The electron released by the Sr90 by itself is only about 0.27 MeV. But combined they have quite an "oomph". And this happens at a rate of 5.21 TBq/g.
Problem is of course that a betavoltaic device would not just be made of Sr90...
So anyway, I did the math and wondered. Why has no one done that? It sounds near perfect. And low an behold... someone did!
https://www.nature.com/articles/srep381 ... 8GsSW7I-CI
"A collection of such devices that generates 100 W would weigh less than 5 kg".
So we get 20 Watts/kg. Not great, but not bad at all. One could make a car battery from that. Of course with Sr90 come other problems... It is extremely dangerous when ingested since it gets integrated into bone. That in turn will likely cause bone cancer. So for consumer applications, it is no darn good.
Plus it will need some shielding too...
Also noteworthy is that Sr90 works better in an RTG where I calculated a power density of ~33 watts/kg (assuming the highest efficiency of 7%). Of course for space applications you will need cooling too then if you want your RTG to work...
Oh well, those nuclear batteries are still a dream that just does not want to come true, I am afraid.