5 ms·

There's only a few grams of hydrogen in the reactor's plasma, it's reaction with oxygen wouldn't be much more exciting than just losing containment. There are

There's only a few grams of hydrogen in the reactor's plasma, it's reaction with oxygen wouldn't be much more exciting than just losing containment. There are engineering challenges that have to be addressed but no worse than the 6 MW research reactor I used to walk by every day to my college classes in the middle of a dense city. The proliferation risk of someone using the neutron flux to produce an atomic or dirty bomb are real but that exists no matter where it is.

leonidasrup 5mo ago
I think the proliferation risks will be in future the reason, independent of technological obstacles or costs, why US will not allow to build fusion power plants in all countries around the world. Hybrid nuclear fusion–fission power plants have been already proposed and studied in theory. "In general terms, the hybrid is very similar in concept to the fast breeder reactor, which uses a compact high-energy fission core in place of the hybrid's fusion core. Another similar concept is the accelerator-driven subcritical reactor, which uses a particle accelerator to provide the neutrons instead of nuclear reactions." https://en.wikipedia.org/wiki/Nuclear_fusion–fission_hybrid https://en.wikipedia.org/wiki/Nuclear_fusion–fission_hybrid
- bleepblap 5mo ago
  > Hybrid nuclear fusion–fission power plants have been already proposed and studied in theory. I have a hand-wavy hard sci-fi universe I've been rolling around my head for years and I eventually came to the conclusion that fission-fusion drives would be really handy for spacecraft, since it would be much easier to start a fission reaction in a cold/dark ship than fusion because of the power requirements. Otherwise you need some other way to generate 10s or 100s of MW to start the fusion reaction.
  - leonidasrup 5mo ago
    Using the energy of fission for spacecraft propulsion has been studied and some prototypes have been already constructed. Most of these nuclear engines should be used only outside of Earths atmosphere. https://en.wikipedia.org/wiki/Nuclear_propulsion https://en.wikipedia.org/wiki/Nuclear_propulsion https://en.wikipedia.org/wiki/NERVA https://en.wikipedia.org/wiki/NERVA Most interesting and promising are direct nuclear propulsions, like fission-fragment rockets. https://en.wikipedia.org/wiki/Fission_fragment_rocket https://en.wikipedia.org/wiki/Fission_fragment_rocket
- DennisP 5mo ago
  Probably not all countries, but any NPT signatory has the right to build nuclear power plants, they just have to submit to inspections.
  - leonidasrup 5mo ago
    This is the basic promise behind the "Treaty on the Non-Proliferation of Nuclear Weapons" (NPT). https://en.wikipedia.org/wiki/Treaty_on_the_Non-Proliferation_of_Nuclear_Weapons https://en.wikipedia.org/wiki/Treaty_on_the_Non-Proliferatio... In the text of the treaty there are promises to NPT signatories, such as: Article IV "1. Nothing in this Treaty shall be interpreted as affecting the inalienable right of all the Parties to the Treaty to develop research, production and use of nuclear energy for peaceful purposes without discrimination and in conformity with articles I and II of this Treaty." https://en.wikisource.org/wiki/Nuclear_Non-Proliferation_Treaty https://en.wikisource.org/wiki/Nuclear_Non-Proliferation_Tre... But the hard reality of U.S. nuclear politics in regard to other countries can be read here: "The Nuclear Fuel Cycle and The Bush Nonproliferation Initiative" https://www.iaea.org/sites/default/files/neff.pdf https://www.iaea.org/sites/default/files/neff.pdf "The world’s leading nuclear exporters should ensure that states have reliable access at reasonable cost to fuel for civilian reactors, so long as those states renounce enrichment and reprocessing." "The 40 nations of the Nuclear Suppliers Group should refuse to sell enrichment and reprocessing equipment and technologies to any state that does not already possess full-scale, functioning enrichment and reprocessing plants." For example when United Arab Emirates wanted to build the Barakah nuclear power plant, (supplied by Korea Electric Power Corporation, not by an U.S. company), it had to sign an the Section 123 Agreement with United States of America. As part of the agreement, the UAE committed to forgo domestic uranium enrichment and reprocessing of spent fuel. https://en.wikipedia.org/wiki/U.S.%E2%80%93UAE_123_Agreement_for_Peaceful_Civilian_Nuclear_Energy_Cooperation https://en.wikipedia.org/wiki/U.S.%E2%80%93UAE_123_Agreement... To be fair, it's not only U.S. who want's the control access to nuclear technology and nuclear materials. For example India wanted to become a member of Nuclear Suppliers Group for a long time. As of 2019, China has thwarted every attempt of India's inclusion into NSG and has made it clear that status quo will remain citing "lack of consensus" among NSG members. https://en.wikipedia.org/wiki/Nuclear_Suppliers_Group#India https://en.wikipedia.org/wiki/Nuclear_Suppliers_Group#India Another example is South Korea. South Korea is constrained in its nuclear power policy by the 1974 Korea-US Atomic Energy Agreement. Only in November 2025 did the USA formally affirmed support for South Korea’s civil uranium enrichment and spent fuel reprocessing for peaceful uses. https://www.armscontrol.org/act/2025-12/news/us-supports-south-korean-enrichment-reprocessing https://www.armscontrol.org/act/2025-12/news/us-supports-sou... https://world-nuclear.org/information-library/country-profiles/countries-o-s/south-korea#fuel-cycle https://world-nuclear.org/information-library/country-profil...
- cyberax 5mo ago
  Fission-fusion or accelerator-driven fission is pure BS. It combines the disadvantages of _both_ and none of the advantages. Modern fission power plants are designed with a reactor vessel to last a century and to withstand high pressures and temperatures. It's built and emplaced permanently in a large concrete shielding structure. In a hybrid design this just won't work. Fuel will need to be right next to a high-vacuum chamber that will need periodic maintenance.

leonidasrup 5mo ago

I think the proliferation risks will be in future the reason, independent of technological obstacles or costs, why US will not allow to build fusion power plants in all countries around the world. Hybrid nuclear fusion–fission power plants have been already proposed and studied in theory. "In general terms, the hybrid is very similar in concept to the fast breeder reactor, which uses a compact high-energy fission core in place of the hybrid's fusion core. Another similar concept is the accelerator-driven subcritical reactor, which uses a particle accelerator to provide the neutrons instead of nuclear reactions." https://en.wikipedia.org/wiki/Nuclear_fusion–fission_hybrid https://en.wikipedia.org/wiki/Nuclear_fusion–fission_hybrid

bleepblap 5mo ago
> Hybrid nuclear fusion–fission power plants have been already proposed and studied in theory. I have a hand-wavy hard sci-fi universe I've been rolling around my head for years and I eventually came to the conclusion that fission-fusion drives would be really handy for spacecraft, since it would be much easier to start a fission reaction in a cold/dark ship than fusion because of the power requirements. Otherwise you need some other way to generate 10s or 100s of MW to start the fusion reaction.
- leonidasrup 5mo ago
  Using the energy of fission for spacecraft propulsion has been studied and some prototypes have been already constructed. Most of these nuclear engines should be used only outside of Earths atmosphere. https://en.wikipedia.org/wiki/Nuclear_propulsion https://en.wikipedia.org/wiki/Nuclear_propulsion https://en.wikipedia.org/wiki/NERVA https://en.wikipedia.org/wiki/NERVA Most interesting and promising are direct nuclear propulsions, like fission-fragment rockets. https://en.wikipedia.org/wiki/Fission_fragment_rocket https://en.wikipedia.org/wiki/Fission_fragment_rocket
DennisP 5mo ago
Probably not all countries, but any NPT signatory has the right to build nuclear power plants, they just have to submit to inspections.
- leonidasrup 5mo ago
  This is the basic promise behind the "Treaty on the Non-Proliferation of Nuclear Weapons" (NPT). https://en.wikipedia.org/wiki/Treaty_on_the_Non-Proliferation_of_Nuclear_Weapons https://en.wikipedia.org/wiki/Treaty_on_the_Non-Proliferatio... In the text of the treaty there are promises to NPT signatories, such as: Article IV "1. Nothing in this Treaty shall be interpreted as affecting the inalienable right of all the Parties to the Treaty to develop research, production and use of nuclear energy for peaceful purposes without discrimination and in conformity with articles I and II of this Treaty." https://en.wikisource.org/wiki/Nuclear_Non-Proliferation_Treaty https://en.wikisource.org/wiki/Nuclear_Non-Proliferation_Tre... But the hard reality of U.S. nuclear politics in regard to other countries can be read here: "The Nuclear Fuel Cycle and The Bush Nonproliferation Initiative" https://www.iaea.org/sites/default/files/neff.pdf https://www.iaea.org/sites/default/files/neff.pdf "The world’s leading nuclear exporters should ensure that states have reliable access at reasonable cost to fuel for civilian reactors, so long as those states renounce enrichment and reprocessing." "The 40 nations of the Nuclear Suppliers Group should refuse to sell enrichment and reprocessing equipment and technologies to any state that does not already possess full-scale, functioning enrichment and reprocessing plants." For example when United Arab Emirates wanted to build the Barakah nuclear power plant, (supplied by Korea Electric Power Corporation, not by an U.S. company), it had to sign an the Section 123 Agreement with United States of America. As part of the agreement, the UAE committed to forgo domestic uranium enrichment and reprocessing of spent fuel. https://en.wikipedia.org/wiki/U.S.%E2%80%93UAE_123_Agreement_for_Peaceful_Civilian_Nuclear_Energy_Cooperation https://en.wikipedia.org/wiki/U.S.%E2%80%93UAE_123_Agreement... To be fair, it's not only U.S. who want's the control access to nuclear technology and nuclear materials. For example India wanted to become a member of Nuclear Suppliers Group for a long time. As of 2019, China has thwarted every attempt of India's inclusion into NSG and has made it clear that status quo will remain citing "lack of consensus" among NSG members. https://en.wikipedia.org/wiki/Nuclear_Suppliers_Group#India https://en.wikipedia.org/wiki/Nuclear_Suppliers_Group#India Another example is South Korea. South Korea is constrained in its nuclear power policy by the 1974 Korea-US Atomic Energy Agreement. Only in November 2025 did the USA formally affirmed support for South Korea’s civil uranium enrichment and spent fuel reprocessing for peaceful uses. https://www.armscontrol.org/act/2025-12/news/us-supports-south-korean-enrichment-reprocessing https://www.armscontrol.org/act/2025-12/news/us-supports-sou... https://world-nuclear.org/information-library/country-profiles/countries-o-s/south-korea#fuel-cycle https://world-nuclear.org/information-library/country-profil...
cyberax 5mo ago
Fission-fusion or accelerator-driven fission is pure BS. It combines the disadvantages of _both_ and none of the advantages. Modern fission power plants are designed with a reactor vessel to last a century and to withstand high pressures and temperatures. It's built and emplaced permanently in a large concrete shielding structure. In a hybrid design this just won't work. Fuel will need to be right next to a high-vacuum chamber that will need periodic maintenance.