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How do plutonium-powered pacemakers work?

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Re: How do plutonium-powered pacemakers work?

#71

Post by c3833174 »

effie wrote: post #65
perlgeek wrote: post #47

Earlier quoted context omitted.

Still, Voyager 1 is slowly shutting down its scientific instruments due to decreased power supply. I highly recommend this podcast episode with one of the Voyager project managers: https://www.listentospacepod.com/episodes/2016/8/5/episode-5... (about 20 minutes long, iirc) (In fact, I'd highly recommend the whole podcast, not just this episode, but this one actually talks about power consumption and battery life of…

The project manager Suzy Dodd talks a lot about shutting down instruments in order to save the power. But the power output of radioisotope thermoelectric generator does not depend on how much power is drawn. Is there a conventional electric battery on the Voyagers that the instruments draw their power from instead?

By saving power she means leaving enough margin to keep the supply voltage stable, running the machine near the limit could cause voltage sag when another device like the tape drive is turned on.

Just like apple limits power draw of it's devices to avoid possible reboots when too much current is demanded from an old battery.

Re: How do plutonium-powered pacemakers work?

#72

Post by dfox »

I'm under the impression that most nuclear powered pacemakers were not based on RTGs which is what the article describes but on betavoltaics (which does not use heat of decay as energy source, but converts beta radiation directly to electricity).

Re: How do plutonium-powered pacemakers work?

#73

Post by littlestymaar »

Laforet wrote: post #27
bunderbunder wrote: post #16

Earlier quoted context omitted.

It sounds to me like it's only a simple "nope" if the only weapons you are worried about are nuclear weapons. Pu-238 could still be useful for radiological weapons such as dirty bombs. If you're worried about them then it becomes a (slightly) more nuanced, "How many morgues do I have to raid, and can I do it before the authorities catch on to the Crematorium Bandit?"

From what I could gather, pacemakers contain up to 4 curies of Pu-238 which is less than 300mg of pure metal. Enough to poison a few people but nowhere near enough to create WMD considering the effort. Industrial radiation sources, in contrast, typically contains tens and sometimes hundreds of curies of mostly undecayed cobalt or iridium isotopes, and is usually much less guarded.

I wouldn't be enough to kill many people, but if a certain amount (even non-dangerous, like 1µS/h) of radiations were detected in all Manhattan, the panic would cause lasting damages.

Re: How do plutonium-powered pacemakers work?

#74

Post by Filligree »

rocqua wrote: post #57
dingo_bat wrote: post #39

Earlier quoted context omitted.

Ambient temperature definitely affects calorie consumption. No doubt about it. Body burns more calories keeping organs at 37C if the exterior is 10C, compared to 40C.

Don't you start to get overheating phenomena at 40C?

If you count "sweating", then sure.

Re: How do plutonium-powered pacemakers work?

#75

Post by littlestymaar »

wolfgang42 wrote: post #18
Rjevski wrote: post #5

Earlier quoted context omitted.

Keeping nuclear material (safely) in your body is the easy part, the hard part is converting that energy into something your body can use. The issue is, our (badly designed) meat-hardware runs on glucose instead of heat or electricity, and there's no easy (or any way that I know of really, but then I'm not a scientist) to convert heat/electricity into glucose.

I went to a lecture recently by a researcher who is investigating the mechanisms of photosynthesis. The chlorophyll uses the energy from the photon to pump an electron, which (after a long and poorly-understood chain of reactions, which is what he was studying) creates an energy gradient which powers ATP synthase to produce ATP. Presumably if we understood and could recreate this reaction, we could create the electro…

> Presumably if we understood and could recreate this reaction, we could create the electrochemical gradient directly

We don't need to reproduce the reaction, we know how to create a potential (in Volt) gradient between two faces of a membrane : you just need electrodes for that purpose.

Re: How do plutonium-powered pacemakers work?

#76

Post by littlestymaar »

ComputerGuru wrote: post #23
Rjevski wrote: post #17

Earlier quoted context omitted.

Isn't heat essentially a by-product of muscles "burning" the glucose? I'm not sure we actually need more heat besides what's already being generated as a by-product.

No, you can actually induce greater caloric expenditure by lowering the ambient temperature (within reason), if I’m not misremembering. This is, after all, the distinguishing characteristic of mammals. Reptiles have no shortage of muscle mass (just look at aligators or crocs!) but still can’t raise their body temperature to compensate for cooler weather or environments.

See https://en.wikipedia.org/wiki/Brown_adipose_tissue

Re: How do plutonium-powered pacemakers work?

#77

Post by johnhenry »

fratlas wrote: post #4

Dumb question, but would it be possible to have a nuclear-powered object in your body producing energy for your body to use?

The ability to metabolize radiation does exist (https://en.wikipedia.org/wiki/Radiotrophic_fungus) so we might be able to modify our genes such that our bodies can use this energy directly.

Re: How do plutonium-powered pacemakers work?

#78

Post by ctdonath »

perlgeek wrote: post #45
Kelbit wrote: post #15

Earlier quoted context omitted.

Easier to replace the whole pacemaker than the battery, for a couple of reasons: * Pacemakers are hermetically sealed, usually laser-welded in a titanium case. Adding a replaceable battery with seals would complicate this arrangement. * By the time the battery winds down, there may be a newer, better pacemaker on the market that fits the patient's needs. * Since a battery replacement necessitates surgery, you might a…

Somebody in my family has a pacemaker, and is fully dependent on it. I can confirm this part: > Easier to replace the whole pacemaker than the battery unfortunately, this statement: > As for how long the cells last, modern Lithium Thionyl Chloride cells last 5-10 years depending on the pacemaker. They probably actually last longer, manufacturers are pretty conservative with lifetime estimates. only partially applies…

I have one. 100% dependent, dynamic rate, wireless interface, logging, runs about 7 years. "Battery low" state is addressed with progressively more annoying behavior (fixed 60 bpm, beat skipping, etc) that both saves power and urges patient to doctor. Whole unit indeed gets replaced (yes, the hard way), no point in fiddling with maintaining old tech and increased point-of-failure interfaces.

And with it, I'm likely healthier than without it & the underlying issue.

Re: How do plutonium-powered pacemakers work?

#80

Post by ctdonath »

rplnt wrote: post #60
Kelbit wrote: post #15

Earlier quoted context omitted.

Easier to replace the whole pacemaker than the battery, for a couple of reasons: * Pacemakers are hermetically sealed, usually laser-welded in a titanium case. Adding a replaceable battery with seals would complicate this arrangement. * By the time the battery winds down, there may be a newer, better pacemaker on the market that fits the patient's needs. * Since a battery replacement necessitates surgery, you might a…

Wouldn't wireless charging pad work well for this? Or is it unnecessary complicated considering how long batteries last?

The issue being rather close to my heart, I'd rather have a single-use 7-year battery + full modern replacement of unit, than have to fiddle with periodic recharging just to prolong use of aging technology. Nobody much wants their life relying on >10 year old computers. (Remember: it's already "old technology" when you first get it implanted.)
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