Timeline for In retrospect, should they have provided more RTG fuel and a more powerful radio for Voyager?
Current License: CC BY-SA 4.0
15 events
| when toggle format | what | by | license | comment | |
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| Dec 6 at 17:54 | comment | added | jwenting | @DarthPseudonym that's the reason it was done, and it's largely bogus. Sure you can extract Plutonium but it will need a lot of work to make weapons grade, requiring large detectable facilities (how we found the Iranian and North Korean programs). That Plutonium can however also be used as fuel for other reactors, greatly reducing the total waste output and cost of running the program. That fear was planted deliberately by the KGB in the 1980s btw, in an effort (somewhat successful) to make the general public think that all nuclear power stations are nuclear bombs. | |
| Dec 6 at 16:28 | comment | added | Darth Pseudonym | @jwenting Ehhh. That restriction I get -- it's basically impossible to distinguish "we're extracting useful stuff out of our spent fuel rods" from "we're extracting weapons-grade material for building bombs" so we made a lot of agreements to just not do that at all. | |
| Dec 6 at 14:59 | comment | added | PM 2Ring | @Sneftel Ok, neutron star mergers produce some plutonium, but only a very tiny amount of that primordial Pu remains, due to its short half-life. A tiny amount of Pu is produced by neutron absorption in uranium ores, but virtually all of our Pu is synthetically produced from uranium. See en.wikipedia.org/wiki/Plutonium | |
| Dec 6 at 11:04 | comment | added | Sneftel | @planetmaker It was the celestial objects that made us all this plutonium, after all. It's time we gave something back. | |
| Dec 6 at 8:18 | comment | added | jwenting | @PM2Ring and while you can extract Np237 (and whatever other isotopes you want) from nuclear waste, current laws and regulations regarding the handling and disposal of nuclear waste prohibit doing so. This is very short sighted as reprocessing waste can help isolate out short and long half life elements, thus greatly reducing the storage cost (and time) for the majority of the waste, and giving potentially useful materials for for example RTGs, nuclear medicine, and other applications. | |
| Dec 6 at 2:48 | comment | added | PM 2Ring | @DarthPseudonym Yes, Hanford was producing Np-237. But it's not a waste product, more like a side product. Np-237 mostly comes from U-235, so if you're already churning out U-235 and have a handy breeder reactor it's feasible to make some Np-237. OTOH, extracting Np-237 from the waste of a natural uranium power reactor is a pain because that waste has a lot of short half-life isotopes that emit nasty beta & gamma radiation. I have some info on Np-237 in physics.stackexchange.com/a/717587/123208 & info on Pu-238 in physics.stackexchange.com/a/705112/123208 | |
| Dec 5 at 22:02 | comment | added | uhoh | @Cadence and from the extra propellant needed to manage all that extra weight | |
| Dec 5 at 20:46 | comment | added | Cadence | Additional weight would have come from the radiators needed to dump all that excess heat, and structural elements to keep the whole thing in one piece. | |
| Dec 5 at 20:45 | comment | added | Darth Pseudonym | Well, okay the Pu-238 is made by neutron bombardment of Np-237, but the neptunium was coming out of Hanford, wasn't it? Which is nuclear weapon production. | |
| Dec 5 at 20:35 | comment | added | Hobbes | @DarthPseudonym no. The Ph-238 used in US RTGs is not a waste product and has to be manufactured separately. | |
| Dec 5 at 17:35 | comment | added | planetmaker | that made my day: mission profile "space heater" :) | |
| Dec 5 at 16:41 | comment | added | Jon Custer | Or, put differently, what instruments would have been deleted in order to fit all the RTGs in. At some point one would have no instruments and be launching a giant space heater. | |
| Dec 5 at 14:20 | comment | added | Darth Pseudonym | IIRC the space program's RTGs were basically using waste material from nuclear weapon development (essentially "depleted plutonium"), so they had a functionally unlimited supply. Today we don't have active nuke construction going on so there's only what's left over. | |
| Dec 5 at 12:33 | comment | added | GremlinWranger | Was enough pu-238 even available at time of launch? In recent history the amount of material has dictated RTG size and number but they were running more reactors then. | |
| Dec 5 at 12:29 | history | answered | Hobbes | CC BY-SA 4.0 |