I doubt that the reluctance to expand the use of fission to other applications is due to a conscious effort to preserve uranium reserves. If that were a main concern, then technologies such as breeding or reprocessing of spent fuel rods would be available to increase usable uranium manifold. I think it’s political controversy, not resource management, that keeps fission power limited to electricity and specialised applications, such as nuclear-powered submarines.
As to the latter point, it may be worth to point out that Russia maintains (as the Soviet Union used to) a fleet of civilian nuclear-powered icebreakers to keep shipping routes in the Arctic navigable.
IMHO, a major problem is that NTP makes sense only if you presume that (1.) rockets are going to be expensive anyway, and (2.) that virtually everything is going to have to be boosted from Earth or from low Earth orbit (LEO). What seems to be happening instead is that development is focusing on cruder but cheaper chemical rockets and in-situ resource utilization, mainly refueling reusable rockets from lunar, Martian or asteroidal resources. This would appear to be adequate for virtually all Earth-orbit, lunar, and Martian activities. Nuclear starts becoming indispensable for extending into the outer solar system, but that’s probably close to a century from now.
We are not lacking in hydrogen on Earth in any way. Almost four fifths of the Earth’s surface is covered in a common, readily available hydrogen-containing compound from which hydrogen can be released by the process of electrolysis which is so simple that it is regularly performed in high school chemistry laboratories, albeit not at efficiencies that makes it favorable for energy production. Hydrogen is really an energy medium rather than a source. Producing hydrogen directly from nuclear fission reactions would be so stunningly inefficient compared to all of the energy that goes into extracting, refining, transporting, enriching, packaging, and managing fuel-grade uranium (notwithstanding that you generally want to avoid producing large quantities of flammable and explosive gas inside of a nuclear reactor for reasons that history has made obvious) that it doesn’t really bear consideration.
No, chemical rockets really aren’t adequate for multi-ton payloads (e.g. crewed missions) anywhere beyond Earth orbit, even assuming some kind of in-situ propellant production (ISPP) in space. The fundamental problem is that even if you have extraterrestrial sources from which to make chemical propellants, the propulsive efficiency, whether you look at it as specific impulse (Isp) or characteristic exhaust velocity (c*) is fundamentally limited by the amount of energy available and momentum developed per unit exhaust mass. This limits the amount of total impulse that can be achieved even if the vehicle is almost all propellants, and thus ensures that interplanetary transfers are essentially Hohmann (minimum impulse) trajectories requiring many months in unprotected interplanetary space during which a crew is exposed to high energy cosmic radiation, solar charged particle radiation, and freefall conditions exceeding that of human experience even in the relative protection of Low Earth Orbit. Only solar electric ion, nuclear ion/plasma, or nuclear thermal provide enough propellant efficiency for interplanetary transits for crewed missions.
Chemical propellants are definitely necessary for high thrust applications such as ascending or propulsive landing onto a planet because the thrust-to-weight ratio of any workable nuclear thermal or nuclear electric propulsion system wouldn’t be able to lift itself even in Lunar gravity, but the fact that the can operate at high propellant mass efficiency for extended periods of time, instead of the few hundred seconds a chemical rocket will operate before exhausting all of its propellants and energy, means that they can significantly reduce transit times to the point that crew would not be running up against lifetime radiation exposure limits or suffer the degradation of freefall conditions for many months, and will make it more practical to build large spacecraft with provisions to protect or mitigate these hazards.
I thought he was talking about hydrogen coming off spent fuel rods being captured and used. Isn’t the hydrogen off the spent rods what blew up the containment buildings at Fukushima?
Says you. Remember that practical joke where you’d put some dry ice in a plastic bottle and put it in a cabinet? 10 minutes later, it over-pressurizes and boom.
Put a spent fuel rod in a sealed metal cylinder and stash it away somewhere. It fills up with helium and hydrogen, and a century later–bang!
In the Fukushima disaster, hydrogen was produced due the zirconium alloy fuel cladding being oxidized by the supercritical steam. The free neutrons have a half life of about 880 seconds, so most of them will be absorbed by other elements (potentially transmuting them into other radioactive isotopes) rather than undergoing beta decay and possibly recombining into a hydrogen atom. Hydrogen is, again, spectacularly abundant on the surface of the Earth at more than 10% by mass of ocean water, so we have no need to manufacture hydrogen via beta decay or any other exotic process.
The production of hydrogen via beta decay of neutrons is not a significant source. And even those these mechanisms can produce enough hydrogen gas to present an overpressure or detonation hazard, it certainly isn’t enough to justify the extreme costs of trying to recover the virtually negligible amount of hydrogen that is produced from a highly radioactive storage facility.
@Stranger_On_A_Train - I have seen Nuclear being touted as the solution to the holy grail of energy storage. Not conventional nuclear power, but a molten sodium salt energy storage system powered by a nuclear reactor.
Basically, the molten salt is used to generate power as needed when the renewable production goes away ( https://natriumpower.com/)
So, it is a little unclear because the website is basically only a promotional blurb with no details other than a couple of non-annotated CAD depictions but that looks like a sodium-cooled fast (neutron) reactor. It has some substantial advantages, and particularly in breeding more fissile material and (potentially) burning up longer lived actinides, but with sodium there is always the concern that a leak could react with the outer water loop (assuming that they are using that for the actual power generation thermal fluid). The “Energy Island” seems to be their fancy technospeak for just using molten salt reservoirs to store thermal energy, allowing for more flexible load balancing compared to a straight reactor thermal output to power generation loop (in which operations to raise or lower reactor output have to be planned out hours in advance) but it still requires enriched and highly processed fuel.
I personally think that the molten salt reactor using distributed fuel actually offers a lot of promise, in no small part because it can use naturally occurring thorium as the primary fuel (although a fissile material has to be used to start the chain reaction process, and mixed fuels provide more efficiency) and can be designed with high specific power output with passive safety. Because it is relatively easy to alter yield with just changes in geometry as opposed to having a fixed array of solid oxide fuel elements and using control rods to increase or decrease neutron flux, they can increase or decrease output relatively quickly, and can be shut down rapidly by just draining the fuel-bearing salt into storage reservoirs with geometry that prevents criticality. They can also be designed as partial or complete burnup reactors (less efficiency for full burnup, but also produces much less and long-lived wastes to be disposed of) and have a substantially reduced embedded carbon footprint in terms materials, construction, and fuel processing/transportation.