# Tritium Tritium is the [[Hydrogen]] [[Isotope]] with two neutrons — radioactive, with a half-life of about twelve years, decaying by [[Beta_decay]] into [[Helium-3]]. That last fact links the two branches of this spine directly: the reactive element decays into the noble one. ## Scarce, and the reason fusion is hard Because it decays, tritium does not accumulate naturally; the world's supply is small and largely a byproduct of certain reactor types. Deuterium–tritium is nonetheless the easiest [[Nuclear_fusion]] reaction to achieve, so a working reactor must breed its own tritium from lithium in a blanket while it runs — a requirement that turns fuel supply into a [[Systems_engineering]] problem rather than a purchasing one. Its decay is also the main terrestrial source of [[Helium-3]], which is why helium-3 is scarce on [[Earth]] and abundant in lunar [[Regolith]] where the [[Sun]] has been depositing it for billions of years. **Reads with:** *Future Energy: Opportunities & Challenges (2013)* — [OTL record](https://open.umn.edu/opentextbooks/textbooks/future-energy-opportunities-challenges) · [download](https://trace.tennessee.edu/entities/publication/48577f98-9b67-472e-bbb3-5d150c80c1e2). Seeded from the Thury Hydrodynamics Apex Spine book shelf. **On the spine:** [[Deuterium]] · [[Helium-3]] · [[Nuclear_fusion]] · [[Isotope]] · [[WT!Thury_Hydrodynamics_Compendium]]. ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Tritium) : [Wikitube](https://en.wikitube.io/wiki/Tritium) ## Previous hub tags Hubs: `Life_Physics`, `Systems`. Portals: [[PORTAL_Thury_Hydrodynamics_Apex_Spine]], [[PORTAL_Hydrogen]], [[PORTAL_Energy]]. --- *Apex Spine wave · 2026-09-10 · stub · microsim layer deferred.*