Fusion reactions whose primary products are charged particles rather than neutrons, offering the theoretical promise of reduced radioactive activation and direct energy conversion.
Aneutronic fusion refers to nuclear fusion reactions in which neutrons are not among the primary reaction products. All of the released energy is carried by charged particles which can in principle be converted to electricity directly.[1]
D–3He is not strictly aneutronic because competing D–D side reactions produce neutrons carrying 5–10% of total fusion power. p–11B is the purest aneutronic candidate.[1]
Reduced activation: Far less neutron damage enables conventional engineering alloys. Direct energy conversion: Charged products can be converted at theoretical efficiencies of 70–90%. Simpler fuel cycle: No tritium breeding blankets needed.[3]
Todd Rider’s 1997 analysis demonstrated that for plasmas in or near thermal equilibrium, bremsstrahlung radiation losses from p–11B can exceed fusion power output at all achievable temperatures, making net energy gain thermodynamically impossible under those assumptions.[2]
Required temperatures are far higher: 50–100 keV for D–3He and 150–300 keV for p–11B, compared with 10–20 keV for D–T.
Aneutronic fusion remains in the early research stage. No experiment has demonstrated net energy gain from an aneutronic fuel. TAE Technologies (D–3He) and HB11 Energy (laser-driven p–11B) are pursuing aneutronic concepts.