Why don't we use Direct-Charging Radioisotope Generators?

[R4D1O]

TL;DR

Information about Direct-Charging Radioisotope Generators and Moseley’s apparatus

when I was browsing wikipedia for some atomic battery information for my school project I found the thing called Direct-Charging Radioisotope Generator and when I tried to find more information about it I did not succeed. So I came here for some information about it or at least an answer why don't we use them.

Support material:
https://en.wikipedia.org/wiki/Atomic_battery
https://www.researchgate.net/publication/332128864_The_design_of_a_direct_charge_nuclear_battery_with_high_energy_conversion_efficiency

 

[Drakkith]

We don't use them for things other than perhaps space probes because atomic batteries are extremely expensive and very dangerous since they can release radioactive material in the event of an accident. There also isn't enough material available to use in large numbers. Naturally occurring radioactive isotopes all have too long of half-lives or occur in too small amounts to be useful, so we are forced to use man-made isotopes from nuclear reactors. Plus these isotopes can't be stockpiled in large amounts since they decay and they present serious hazards even in storage.

 

[R4D1O]

But what about Strontium-90? It is considered as a waste but in the same time can be used for Generators to power something up. As I can see the main source of price in the atomic batteries is the nuclear element itself and Strontium is way cheaper then Plutonium that everyone uses. The DCRG is pretty good side to try to work in cause we can use it for impulse oriented mechanisms. But in the same time no one is doing that and I can't understand why.

 

[Drakkith]

But what about Strontium-90? It is considered as a waste but in the same time can be used for Generators to power something up. As I can see the main source of price in the atomic batteries is the nuclear element itself and Strontium is way cheaper then Plutonium that everyone uses.

The only source of strontium-90 is spent nuclear fuel, which still makes it very expensive.

The DCRG is pretty good side to try to work in cause we can use it for impulse oriented mechanisms. But in the same time no one is doing that and I can't understand why.

Probably because it's expensive and dangerous to produce and use.

 

[artis]

@R4D1O And they are also known for low power output. The advantage is they can output that power for a very long time but in a practical setting the power output from a radioisotope electrical generator won't be able to power your laptop, or you would need a large one.
Energy density is one thing but energy output per time is another.

Radioisotopes that for example emit beta radiation (electrons) can do that for decades and if you summed up the total emission converted to electrical current it would be large but at any given moment the current is small it's just spaced out over a long time duration.

It's a niche thing.

 

[anorlunda]

The most successful "atomic batteries" ever are in the Voyager 1 and Voyager 2 spacecraft . Unmanned spacecraft don't care if it is radioactive.

https://en.wikipedia.org/wiki/Voyager_1#Power
Voyager 1 has three radioisotope thermoelectric generators (RTGs) mounted on a boom. Each MHW-RTG contains 24 pressed plutonium-238 oxide spheres.[24] The RTGs generated about 470 W of electric power at the time of launch, with the remainder being dissipated as waste heat.[25] The power output of the RTGs declines over time due to the 87.7-year half-life of the fuel and degradation of the thermocouples, but the craft's RTGs will continue to support some of its operations until 2025.

 

[Tom.G]

As @artis noted:

And they are also known for low power output.

Many years ago I did a literature search for a client that wanted a power source that could be stored for at least 100 years and could power a record player (weird, don't ask).

Direct output Atomic Batteries (the charged radiation particles collected on a conductor to supply electricity) were considered but rejected because the available current was quite low, in the microamp range if I recall correctly; the voltage, however, was in the kilovolt range.

Transistor circuits have trouble with both the voltage and the radiation.

Unfortunately, that is a nice idea that is not practical for most applications.

Cheers,
Tom

 

[R4D1O]

As @artis noted:

Many years ago I did a literature search for a client that wanted a power source that could be stored for at least 100 years and could power a record player (weird, don't ask).

Direct output Atomic Batteries (the charged radiation particles collected on a conductor to supply electricity) were considered but rejected because the available current was quite low, in the microamp range if I recall correctly; the voltage, however, was in the kilovolt range.

Transistor circuits have trouble with both the voltage and the radiation.

Unfortunately, that is a nice idea that is not practical for most applications.

Cheers,
Tom

But what if we use them for charging up capacitors or as the capacitors for Gauss canon or Railgun?

 

[Alex A]

@R4D1O You might want to think about what your last question means. Anything that uses a lot of energy is better getting it from a source that can produce that energy rapidly. Even if it's an internal combustion engine.

Bulk radioisotopes produce low power per unit volume. Watts per kilogram range for long lived sources. Direct drive is a surface effect, and the overall power per unit volume of the generator drops to something so low as to have no real use. There are ways of improving this, which for example use layers like a solar panel to gather energy from low energy beta, but these are going to significantly impact that lifespan and suffer other problems.

 

[hutchphd]

But what if we use them for charging up capacitors or as the capacitors for Gauss canon or Railgun?

Do you think it wise to carry around a capacitor charged to a million volts? The energy of the beta and alpha particles is very high (volts) and the current is very low (unless you are at Chernoble) as mentioned by others. Not a practical source.

 

[Vanadium 50]

But what if

Sounds like a solution in search of a problem.

 

[Drakkith]

But what if we use them for charging up capacitors or as the capacitors for Gauss canon or Railgun?

Unless your weapons are being mounted on a space probe that's being launched into a multi-decade mission away from the Sun then you're better off using nearly any other option. The ONLY benefits atomic batteries have over other power sources is their very high energy density and very long life. These two reasons are the only reasons they have any real world use at all. And the drawbacks are so large that the only uses they get are on space probes where there just aren't any other reasonable options.

 

[anorlunda]

This video may have been the stimulus for the OP. They are talking about 100 microwatt battery powered by nuclear waste with a lifetime of thousands of years. It's not crazy, but it has never moved from concept to a real prototype. It generated much hype as you might expect.