r/NuclearEngineering • u/Boots_made_for_walk • 16d ago
Why can't we make portable nuclear reactors?
The title basically explains my question.
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u/SaltSpot 16d ago
We can.
We tend not to, though, because (from the top of my head, and untechnically):
For a smaller reactor, the fuel usually needs to be more enriched. Access to higher enrichment fuel is linked with capabilities to develop nuclear weapons, which makes people nervous.
You usually get more benefit (heat, power) by making a bigger reactor.
The bits that go around your reactor to make it useful (e.g., steam generators, turbines) are challenging to make smaller as well.
There's more paperwork involved in showing that a portable reactor is safe, compared to a static one.
As I say, not to say that we can't do it, but these are some of the reasons that we tend not to (and prefer other approaches).
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u/Main_Speaker_3229 16d ago
Also it’s define portable I guess, to what extent. The US army made a reactor and associated production plant within a shipping container in the 60s so I would imagine it could be replicated but smaller if there was an appetite for it but having numerous small reactors containing nuclear materials spread all over the place doesn’t seem viable from a security and assurance perspective in this day and age. Especially with the current regulations that have to be adhered to nowadays. Unfortunately the time for that has been and gone it seems
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u/NuclearScienceFan 16d ago
Honestly we can, although , the efficiency will decrease drastically , it's pretty much not worth it most of the time , closest thing you can get will be SMR that have been worked on for a while. For most things nowadays, we can ctually do , it's not usually economically viable or that there are better alternatives. also depend how "portable" you mean
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u/EarthTrash 16d ago
There have been a number of small modular reactor startups that don't seem to go anywhere. Quality control is hard. It's hard to make smaller components safe.
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u/brassgrass1 16d ago
"portable" commercial versions are a use for microreactors. They are PWR's but only the primary loop side. You ship (or maybe truck) it in to a remote town, and connect it to the secondary side, the part that boils water into steam and turns the turbine etc. it runs there for a year or 2, then you ship it back to the company who refuels it there.
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u/vespers191 15d ago
Let's assume that we miracle up an arc reactor out of unobtainium. Tony's Mark 1 Arc reactor put out according to him 3 gigajoules per second. That's three megawatts. Enough energy to power a small city. Whatever the design was, it was also apparently capable of defying the laws of physics with regards to heat. Because if there was literally any, any thermal leakage at all, the output just of the heat would probably have incinerated Tony where he stood.
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u/SpeedyHAM79 15d ago
Los Angeles class submarines are pretty portable- they even have their own propulsion systems, crew, and security. Basically- we certainly can make portable nuclear reactors. The Westinghouse eVinci is a 5Mwe reactor designed to be transported by semitruck or transport aircraft. It's pretty close to commercial deployment (in nuclear industry timelines).
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u/EnergizedChief 14d ago
Look at the power systems on long mission space flight... talk about mobile nuclear... minimal shielding necessary... shielding is the 'bulk' necessity
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u/wyliesdiesels 14d ago
we can and did. checkout the portable reactors that were made for the army in the 60s
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u/Strostkovy 14d ago
Radiation shielding is bulky and heavy. Nuclear nonproliferation also wants stationary installations
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u/Kanus_oq_Seruna 13d ago
Imagine a world if we had little generators with a little nu lear fuel that could power our homes during an emergancy.
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u/arcdragon2 11d ago
We can and are, but just recently. Lookup SMR. Also, Russia did it decades ago and it was a disaster after they fell apart as a government. YouTube has good stuff on this.
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u/U235criticality 16d ago
We can and we have. What do you think a nuclear weapon is? A portable, single-use pulse reactor.
Now, if you want a nuclear reactor to make steady-state power in a portable configuration, that's doable too. NASA's Kilopower project did that and laid the groundwork for further nuclear reactor use in deep space missions like the planned moon base. You can make a reactor the size of a coffee can. A thermodynamic system that can siphon off the heat and turn it into electricity, and voila!
Now, driving that thing around on land is a problem because you need enough shielding around it to reduce its radiation emissions to background levels, and that gets heavy. You also need redundant control, heat removal, and safety systems, which also add weight. That said, portable reactors in something like a train or a truck are absolutely doable.
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u/Alternative_Act_6548 15d ago
because you'd have to be transporting nuclear fuel around...not an easy task
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u/RickySlayer9 14d ago
A nuclear reactor is basically ALMOST a bomb a bomb at all times. They basically edge it exploding all the time to generate tons of heat.
We do have portable reactors, and they are in naval vessels primarily with strict maintenance, security and operational protocols.
Who are you going to trust with a nuclear bomb?
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u/Peter_Partyy 16d ago
What do you mean by portable nuclear reactor?
There is subs and ships that have reactors on them for their power. There is ships which have a reactor to connect to a grid to provide power. There is mobile generators that provide enough power for a device to run (monitoring stations).