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NASA Struggles Over Deep-Space Plutonium Power
- psswrdshmashwrd 11y agoTwo words: Thorium reactor.
- cstross 11y agoPlease explain how you would design a thorium reactor to produce 238Pu suitable for use in RTGs. Please explain how you would build a shiny new thorium reactor with 238Pu production capability on a budget competitive with the existing DoE 237Np -> 238Pu transmutation process in an existing research reactor.
- psswrdshmashwrd 11y agoPlease see: Liquid fluoride thorium reactor
- humbleMouse 11y agoYeah, weird why that is getting down-voted.
- PhantomGremlin 11y agoIt should get down-voted. The original post was two words. Okay, cute. But then the subsequent "explanation" was four words. There should have been at least a sentence or two of explanation. At the minimum there could have been a link to Wikipedia. That's common courtesy. Most people don't come to HN to spend decades learning obscure things, very slowly, from Zen masters.
- jobu 11y agoThe wikipedia page doesn't say much about Pu-238, but there is this under the "Proliferation resistance" bullet: "...LFTRs produce very little plutonium, around 15 kg per gigawatt-year of electricity (this is the output of a single large reactor over a year). This plutonium is also mostly Pu-238..." https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor#Safety https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reacto... In a LFTR the fuels are dissolved in liquid salts, so the downside is it may be very difficult to separate out the Pu-238 for use.
- jb55 11y agoTake a look at http://www.thoriumenergyalliance.com/downloads/plutonium-238.pdf http://www.thoriumenergyalliance.com/downloads/plutonium-238... for how it could be done
- rexignis 11y agoEvery time someone gets all giggly about Thorium I'm suspicious. Could you provide some documentation about why this is a viable option in space?
- deleted 11y ago[deleted]
- psswrdshmashwrd 11y agoI agree thorium isn't without its problems, but the end byproduct of a lftr reactor is plutonium.
- oppositelock 11y agoLFTR's produce 239Pu (among a mess of other stuff), that's the stuff that goes BOOM in nuclear bombes, not 238Pu that glows warmly to make power for spacecraft.
- Roodgorf 11y agoAs Jobu points out from Wikipedia: he second proliferation resistant feature comes from the fact that LFTRs produce very little plutonium, around 15 kg per gigawatt-year of electricity ... This plutonium is also mostly Pu-238. According the article this seems like quite a bit more than is currently being produced, is it not viable for use in RTGs for some reason? Or is the cost of a LFTR over the course of a year less cost effective than the current method of Np to Pu? I have very little knowledge of the science here, I'm just not sure what all I'm missing.
- Vexs 11y agoAFAIK it's because they last a long time with very small amounts of reactants, are low maintenance, and are potentially very small. I mean, it kinda makes sense but RTGs are better for space applications because you really don't need massive amounts of power in space, plus the whole "power forever with no effort" aspect; they might as well be perpetual motion engines.
- obfk 11y agoThe Thorium Dream (Documentary): https://www.youtube.com/watch?v=GQ9Ll5EX1jc https://www.youtube.com/watch?v=GQ9Ll5EX1jc
- Symmetry 11y agoI have no idea what you're getting at here. If you mean we should use a Thorium reactor to generate Plutonium then others have explained why that's impossible. If you mean that we should use a Thorium reactor instead of a Plutonium RTG then that also wouldn't work, the smallest reactor is still way heavier than an RTG.
- jtwebman 11y agoIt is sad we spend so much money on military yet can't give NASA more money. I hate politics!
- Vexs 11y agoHonestly, we could probably support the same sized military with substantally less money, due to all the waste and mismanagement. Honestly though, it's not just the military- massive waste occurs at all levels of govt. All this focus on cutting spending; yet nobody ever seems to seriously look at waste as a better alternative to public spending. I guess because it's harder to investigate than to cut from a spreadsheet. Small story from reddit: This guy worked in a government office where his boss would order multi-thousand page reports to be rush delivered to the office, which cost anywhere from hundreds to thousands of dollars depending on the report; and then took a single paper out and trashed the rest- because she didn't know you could just print single pages.
- omegaham 11y agoHaving served in the military, I don't think it's possible; the military wastes so much precisely because it's so big. Waste is inherent to large organizations. More administration, less flexible thinking, more room for fraud, waste, and abuse to go unnoticed. Want less waste? Make it smaller. This will, of course, decrease its capabilities (which might not be a bad thing). If you want it to have the same capabilities as it currently has, the waste is going to stay as an unpleasant side effect.
- justin66 11y ago> Having served in the military, I don't think it's possible; the military wastes so much precisely because it's so big. Well, a big chunk of what we talk about when it comes to military spending is developing new weapons systems. The nature of the cost problems there is a little different.
- knz 11y agoThe OP makes the mistake of assuming that waste only occurs in Government agencies. As you mentioned - larger organisations tend to create more waste.
- drzaiusapelord 11y agoThis is such a non-issue (from the article): “The project is planning to produce new Pu-238 at a rate that supports currently projected NASA missions,” says Rebecca Onuschak, program director for the DOE’s plutonium infrastructure. “There is no shortfall of material projected to meeting those needs, and so no remedy or action plan has been implemented.” --- The argument that if NASA had more RTG's laying around it would be doing more is a bit suspicious as that's not how space missions are planned. Not to mention, Charles Bolden just wrote a letter to Congress asking them why they can't fund the SLS properly. There's no extra money laying around.
- sehugg 11y agoI think you've got it wrong; Bolden is mad at Congress for funding SLS at the expense of Commercial Crew, which includes SpaceX and Boeing's new CST-100 vehicle: http://spaceflightnow.com/2015/06/11/commercial-crew-spaceships-face-likely-delays/ http://spaceflightnow.com/2015/06/11/commercial-crew-spacesh... SLS is a white elephant that currently has nothing to do. The first crewed mission is scheduled for 2021, and plans beyond that are hazy. NASA managers have looked into "how seldom" they can launch the thing while still maintaining a safe and viable program. And the article describes a chilling effect which keeps plutonium-dependent missions from being seen as viable, so of course there will be enough plutonium for all the planned missions (of which there are precious few).
- drzaiusapelord 11y agoBolden very clearly stated that he's upset that there's money for all these Russian ISS launches, but not for his SLS and the CCV programs. There is no bigger cheerleader for CCV than Bolden. This SLS vs CCV "controversy" is 100% manufactured. http://www.theverge.com/2015/8/28/9221541/NASA-Charles-Bolden-Congress-open-letter http://www.theverge.com/2015/8/28/9221541/NASA-Charles-Bolde... It costs around $81 million to send just one astronaut on the Soyuz. Bolden says it will only cost $58 million per seat to send astronauts on the Commercial Crew vehicles. "It’s as if we keep ordering expensive takeout because we haven’t yet set up our own kitchen — only, in this case, the takeout meals are costing us hundreds of millions of dollars," he writes.
- akshayB 11y agoNASA's budget is way less then what USA gives out in international aid to other countries at times which is in a way used to buy influence in that region of the world. It is a tragedy how politicians decide to use their brain in general.
- rebootthesystem 11y ago> It is a tragedy how politicians decide to use their brain in general. The terms "politician" and "brain", when put together, result in a null pointer. A problem has been detected and Congress has been shut down to prevent damage. DRIVER_IRQ_POLITICIAN_ATTEMPTED_TO_USE_BRAIN If this is the first time you see this Exception: BrainUseAttempt message, restart Congress. If this screen appears again, follow these steps: ....
- Symmetry 11y agoI wouldn't call it "way less." We spend $32 billion on aid compared to $18 billion for NASA. Those are large numbers but they're not so very different considering the $4 trillion total.
- sageabilly 11y ago"...maintaining it all costs upwards of $50 million per year" It's really dumb that we're going to sit in ignorance of SO MUCH STUFF because someone in the government somewhere is getting into a tiff over this tiny, tiny drop in the government budget. For some perspective, apparently the US Gov spends about $1.7 Billion annually maintaining empty or abandoned federal buildings/land [1] [1] http://www.npr.org/2014/03/12/287349831/governments-empty-buildings-are-costing-taxpayers-billions http://www.npr.org/2014/03/12/287349831/governments-empty-bu...
- ekianjo 11y ago> about $1.7 Billion annually maintaining empty or abandoned federal building and a lot more on killing people overseas.
- knieveltech 11y agoWell, they weren't gonna kill themselves... Edit: Seriously? Y'all downvote the parent and upvote this blatantly inflammatory nonsense? Clearly I have no idea what motivates people.
- MrZongle2 11y agoHumor is rarely permitted on HN, for fear that it would suddenly turn the site into Reddit. Somehow.
- NegativeK 11y agoEach of those buildings costs less than $50M per year to maintain. I, personally, am absolutely for giving NASA a lot more money -- even if it's $50M for plutonium production. But the "it's a drop in the bucket" argument isn't really a viable argument when national budgets are just heaps of drops in a really big bucket.
- dghughes 11y agoWhy not use polonium? It's very rare but at least it's not as rare as an element that has to be actually be created. The Russians use polonium for the same purpose in their spacecraft as the US does using plutonium; heat to generate power suing thermoelectric generators.
- zaphoyd 11y agoPolonium 210 has a half life of 138 days vs 88 years for Plutonium 238. I believe Russia used it for short duration moon missions. For missions that last years or decades it is not an option.
- MrZongle2 11y agoOh, the Russians use polonium for a lot of things. cough https://en.wikipedia.org/wiki/Poisoning_of_Alexander_Litvinenko https://en.wikipedia.org/wiki/Poisoning_of_Alexander_Litvine...
- Aldo_MX 11y agoWhy don't they take the fuel from their nuclear missiles?
- tsotha 11y agoIt's not the same isotope.
- fluxquanta 11y ago>Pu-238 cannot be used to make atomic bombs, nor is it particularly useful for fueling nuclear reactors, which are widely considered too controversial and expensive for practical use in space missions. Look up the difference between Pu-238 and Pu-239 (what most nuclear warheads carry) and deduce why shooting a rocket filled with Pu-239 might be a bad idea.