Nuke battery?

[ltiu]

http://www.technologyreview.com/energy/23959/?nlid=2518&a=f

This is how they run Voyager and Pioneer.

 

[bshanahan14rulz]

That's awesome! tritium is more than a weak radioactive oddity, eh?

 

[RaVeN38571]

Can't wait for the AA size warp core.

 

[uk_caver]

I'm not sure about the maths in the article:

"To make a battery that lasts 25 years from tritium, which has a half-life of 12.3 years, Widetronix loads the package with twice as much tritium as is initially required."

Surely, after 25 years, a tritium-powered package will have ~1/4 of the original tritium left?

 

[balou]

http://www.technologyreview.com/energy/23959/?nlid=2518&a=f

This is how they run Voyager and Pioneer.

No, they use a different system in those space probes. It's called Radioisotope thermoelectric generator (http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator). It's just radioactive material that's literally hot enough to create substantial amounts of heat. The temperature difference between the radioactive material and the outside is then converted into electrical energy using thermocouples.

This one is basically a tritium vial with a solar cell attached to it (yeah, no vial and no 'solar', but you get the idea)

The prototype being tested by Lockheed Martin produces 25 nanowatts of power.

That's very, very little power. In any system less critical than warheads or other military technology, other energy harvesting (http://en.wikipedia.org/wiki/Energy_harvesting) technologies are probably better suited.
In comparison, RTGs can put out several hundreds of watt of electric energy and thousands of watts of heat.

 

[Mark620]

Using Uranium-238(4.51 x 10^9 yrs) would make a battery that would last...like a real everlasting battery (the bunny would be so jealous):nana:

 

[LightCannon]

I'm not sure about the maths in the article:

"To make a battery that lasts 25 years from tritium, which has a half-life of 12.3 years, Widetronix loads the package with twice as much tritium as is initially required."

Surely, after 25 years, a tritium-powered package will have ~1/4 of the original tritium left?

Yes, but it's 1/2 of the amount needed to keep the thing juiced.

 

[uk_caver]

So the 'twice as much as initially required' isn't actually anything to do with the half-life, but is some kind of additional safety factor, with activity an initial 8x multiple on required final output?

Or is it that they usually make devices to last 12.5 years, but make double-strength devices (an initial 4x multiple on required final output) for 25-year use by the military?

 

[Mark620]

I'm not sure about the maths in the article:

"To make a battery that lasts 25 years from tritium, which has a half-life of 12.3 years, Widetronix loads the package with twice as much tritium as is initially required."

Bad wording/use by the Author!

Surely, after 25 years, a tritium-powered package will have ~1/4 of the original tritium left?

No matter how much tritium you started with.


It has to do with backing into the amount needed given the half life and desired useful life of the device.

If you need 2 grams at the end of life to power the device(when the fuel falls below this amount the device will not "work" or function well enough)

half life calculation:

Half life of Trituim is 12.3 years
you would need 2X that amount for 12.3 years
You would need 4X that amount for 24.6 years
you would need 8X that amount for 36.9 years
you would need 16X that amount for 49.2 years
etc.

If you notice that the auhtor has 25 years but 12.3 x 2 = 24.6 years...