Abstract
A compact spherical-tokamak breeder whose size is set by an isotope-supply requirement rather than by electrical output. Across 25,200 configurations the minimum plasma current meeting a national tritium duty falls to 4.93 MA — a third of ITER's — and tritium breeding is presented as an openly-shown blanket lever (demonstrated beryllium-multiplied TBR ≈ 1.34, with an advanced-blanket development target above it). Helium-3, the strategic product, is bred independently of the blanket.
This paper is Open Access (CC BY 4.0). Every headline number regenerates from the named script and archived data in the deposit above; requirement-class assumptions and open risks are stated in the manuscript rather than absorbed into a single optimum. No financial or commercial information appears in this work.