Helium Cycle Fusion (HCF) Reactors are the current state of the art in power generation throughout the Union. They are widely scalable and can produce power from a half-gigawatt up to nearly one-terawatt.
Utilizing helium as a fuel source, these reactors are the most powerful magnetodynamic fusion devices possible, due to quantum-scale limitations of superconducting magnet systems.
Larger class vessels such as the Jakob Waltz (D class keel) and the larger Multicruisers (D and E class keels) will use multiple HCF Reactors to provide system redundancy and ample auxiliary power for specialty operations for extended duration missions. Some Sagan Class Science vessels, and all Hawking Class Science vessels, have paired or triplet HCF Reactors.
Earlier Hydrogen Magnetodynamic Fusion (HMD) Reactors are still in widespread use but the volatility of hydrogen and the hazards of storing it are leading to a general abandonment of the earlier technology.
More advanced reactor technology (See Hyperfusion Project) does exist but has not reached widespread use because of the complexity of the system. Because of this the HCF Reactor system remains the workhorse of the Union.